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Purpose: Working parents, and a rising number of adults delivering care for aging relatives, experience numerous challenges in their personal, family, professional, and financial lives owing to multiple responsibilities. This study describes the experiences of Canadian radiation oncologist (RO) parents and family caregivers, reporting challenges that may exist in providing family care with clinical and academic work commitments., Methods and Materials: Canadian ROs, via RO heads of departments in cancer centers across Canada, and physician members of the Canadian Association of Radiation Oncology were invited to participate in an anonymous online survey between November 2021 and January 2022. The survey focused on demographics, experiences of pregnancy and leave, parenting and adult caregiving responsibilities, and self-care., Results: A total of 103 staff ROs (38%) completed the survey and 78 (75.7%) identified as having a parental (76 [89.7%]) and/or other family caregiver (8 [10.3%]) role; 41% were female and 59% were male, with no difference between genders in the number of children (median, 2; interquartile range, 1-3; P = .17). More female respondents took parental leave for their first child compared with male respondents (mean, 29 vs 6 weeks; P < .001). Of male respondents who started caring for their first child during residency, 27% took parental leave, compared with 77% who started caring for their first child as a staff member (P = .003). The majority of respondents described "always/usually" having collegial support for each pregnancy and parental leave. Both genders described parental responsibilities as negatively affecting attendance at conferences (male, 65%; female, 77%; P = .31) and early or late work-related meetings (male, 76%; female, 79%; P = 1.0). More female respondents described parental responsibilities as negatively affecting their career (50% vs 29%; P = .085). Of female respondents, 52% (vs 26% of male respondents; P = .044) identified a physician mentor or positive role model around parenting issues., Conclusions: Parental and other family caregiving responsibilities are not gender unique in Canadian ROs, but competing work and family roles may affect genders differently., (Copyright © 2022 Elsevier Inc. All rights reserved.) more...

Purpose: Using the primary endpoint of time to biochemical progression (TTP), Androgen Suppression Combined with Elective Nodal and Dose Escalated Radiation Therapy (ASCENDE-RT) randomized National Comprehensive Cancer Network patients with intermediate and high-risk prostate cancer to low-dose-rate brachytherapy boost (LDR-PB) or dose-escalated external beam boost (DE-EBRT). Randomization to the LDR-PB arm resulted in a 2-fold reduction in biochemical progression compared with the DE-EBRT group at a median follow-up of 6.5 years (P < .001). Herein, the primary endpoint and secondary survival endpoints of the ASCENDE-RT trial are updated at a 10-year median follow-up., Methods: Patients were randomly assigned to either the LDR-PB or the DE-EBRT arm (1:1). All patients received 1 year of androgen deprivation therapy and 46 Gy in 23 fractions of pelvic RT. Patients in the DE-EBRT arm received an additional 32 Gy in 16 fractions, and those in the LDR-PB arm received an 125 I implant prescribed to a minimum peripheral dose of 115 Gy. Two hundred patients were randomized to the DE-EBRT arm and 198 to the LDR-PB arm., Results: The 10-year Kaplan-Meier TTP estimate was 85% ± 5% for LDR-PB compared with 67% ± 7% for DE-EBRT (log rank P < .001). Ten-year time to distant metastasis (DM) was 88% ± 5% for the LDR-PB arm and 86% ± 6% for the DE-EBRT arm (P = .56). There were 117 (29%) deaths. Ten-year overall survival (OS) estimates were 80% ± 6% for the LDR-PB arm and 75% ± 7% for the DE-EBRT arm (P = .51). There were 30 (8%) patients who died of prostate cancer: 12 (6%) in the LDR-PB arm, including 2 treatment-related deaths, and 18 (9%) in the DE-EBRT arm., Conclusions: Men randomized to the LDR-PB boost arm of the ASCENDE-RT trial continue to experience a large advantage in TTP compared with those randomized to the DE-EBRT arm. ASCENDE-RT was not powered to detect differences in its secondary survival endpoints (OS, DM, and time to prostate cancer-specific death) and none are apparent., (Copyright © 2022 Elsevier Inc. All rights reserved.) more...

Purpose: The aim of this study was to characterize the patterns of prostate cancer recurrence after brachytherapy (BT) using 2-(3-[1-carboxy-5-([6- 18 F-fluoropyridine-3-carbonyl]-amino)-pentyl]-ureido)-pentanedioic acid ([ 18 F]DCFPyL) prostate-specific membrane antigen (PSMA) positron emission tomography (PET) and computed tomography (CT) imaging., Methods and Materials: Patients were selected from an ongoing prospective institutional trial investigating the use of [ 18 F]DCFPyL PSMA PET and CT in recurrent prostate cancer (NCT02899312). This report included patients who underwent BT (either monotherapy or boost) and experienced a biochemical failure (BF) defined by the Phoenix definition (prostate-specific antigen [PSA] > 2 ng/mL above nadir)., Results: Between March 2017 and April 2020, 670 patients underwent [ 18 F]DCFPyL PSMA PET and CT imaging. Of these 670 patients, 93 were treated with BT; 73 underwent monotherapy, and 20 underwent BT boost (19 low-dose rate and 1 high-dose rate). To report on patterns of recurrence outcomes, 86 patients (median prescan PSA 6.0) with a positive [ 18 F]DCFPyL PSMA PET and CT scan and true BF were included. The most common location of relapse was local; 62.8% had a component of local failure (defined as prostate and/or seminal vesicles), and 46.5% had isolated local failure only, with no other sites of involvement. Regional failure occurred in 40.7% of patients, and 36.0% had metastatic failure. Isolated local recurrence was seen in 54.3% of monotherapy patients versus only in 12.5% of boost patients. Metastatic failure was seen in 28.6% of monotherapy patients versus 68.8% of the boost patients. Local recurrences (69.0%) were found within the same prostate biopsy sextant involved with the tumor at diagnosis, and 76.0% of patients with seminal vesicle recurrences had prostate-base involvement at diagnosis., Conclusions: Contrary to previous evidence, our study suggests that in prostate BT patients with biochemical recurrence, the most common site of failure is local for the patients treated with monotherapy and metastatic for patients treated with a combination of external beam radiation and BT boost., (Copyright © 2021. Published by Elsevier Inc.) more...

Purpose: To determine whether the use of 6 months' adjuvant androgen deprivation therapy (ADT) combined with brachytherapy for intermediate-risk (IR) and low-risk (LR) prostate cancer is associated with an increased risk of cardiovascular death., Methods and Materials: This is a retrospective analysis of prospectively collected data from men treated in the British Columbia Cancer Agency brachytherapy program from 1998 to 2012. Men were categorized by risk group and ADT use. Cardiac and other comorbidities were recorded and compared between groups. Biochemical control (Phoenix definition, nadir + 2 ng/mL) was ascertained. Overall, prostate, cardiac, and other-cause mortality were analyzed by the Kaplan-Meier method and Fine and Gray competing-risk analysis., Results: The study included 3155 men (1142 with LR cancer and 2013 with IR cancer) who have been followed up for a median of 7.9 years. ADT was received by 47% of IR patients and 37% of LR patients for a median of 6 months. Men with IR cancer were older and had more cardiac and other comorbidities than LR cases (P<.01). Biochemical control improved from 86% to 89% at 10 years with the use of ADT (P=.006). Overall survival was inferior in patients receiving ADT (84% vs 86% at 10 years, P=.0274), and on competing-risk analysis, cardiovascular mortality in patients receiving ADT was higher in IR cases, 5.2% versus 3.6% at 10 years (P=.0493), but not in LR cases. Multivariate analysis confirmed increased cardiac mortality in IR patients receiving ADT (hazard ratio, 1.95 [95% confidence interval, 1.15-3.34]; P=.014)., Conclusions: ADT adds little meaningful benefit in terms of biochemical control for IR men treated with low-dose-rate brachytherapy but likely decreases overall survival because of increased cardiac mortality. IR patients were older and had more cardiac risk factors than LR prostate cases; this may be because of a screening effect, case selection, or common etiologic cause., (Copyright © 2017 Elsevier Inc. All rights reserved.) more...

Purpose: To report the genitourinary (GU) and gastrointestinal (GI) morbidity and erectile dysfunction in a randomized trial comparing 2 methods of dose escalation for high- and intermediate-risk prostate cancer., Methods and Materials: ASCENDE-RT (Androgen Suppression Combined with Elective Nodal and Dose Escalated Radiation Therapy) enrolled 398 men, median age 68 years, who were then randomized to either a standard arm that included 12 months of androgen deprivation therapy and pelvic irradiation to 46 Gy followed by a dose-escalated external beam radiation therapy (DE-EBRT) boost to 78 Gy, or an experimental arm that substituted a low-dose-rate prostate brachytherapy (LDR-PB) boost. At clinic visits, investigators recorded GU and GI morbidity and information on urinary continence, catheter use, and erectile function. Exclusion of 15 who received nonprotocol treatment and correction of 14 crossover events left 195 men who actually received a DE-EBRT boost and 188, an LDR-PB boost. Median follow-up was 6.5 years., Results: The LDR-PB boost increased the risk of needing temporary catheterization and/or requiring incontinence pads. At 5 years the cumulative incidence of grade 3 GU events was 18.4% for LDR-PB, versus 5.2% for DE-EBRT (P<.001). Compared with the cumulative incidence, the 5-year prevalence of grade 3 GU morbidity was substantially lower for both arms (8.6% vs 2.2%, P=.058). The 5-year cumulative incidence of grade 3 GI events was 8.1% for LDR-PB, versus 3.2% for DE-EBRT (P=.124). The 5-year prevalence of grade 3 GI toxicity was lower than the cumulative incidence for both arms (1.0% vs 2.2%, respectively). Among men reporting adequate baseline erections, 45% of LDR-PB patients reported similar erectile function at 5 years, versus 37% after DE-EBRT (P=.30)., Conclusions: The incidence of acute and late GU morbidity was higher after LDR-PB boost, and there was a nonsignificant trend for worse GI morbidity. No differences in the frequency of erectile dysfunction were observed., (Copyright © 2017 Elsevier Inc. All rights reserved.) more...

Objectives: This study examined patterns of recurrence after low-dose-rate prostate brachytherapy (LDR-PB), estimated local recurrence rate and compared that rate to the estimated local recurrence rate after radical prostatectomy (RP)., Methods and Materials: A prospective database was maintained with clinical, dosimetric, and outcome data for all LDR-PB implantation procedures performed at our institution. From 1998 to 2008, 2223 patients with prostate cancer received LDR-PB without supplemental external beam radiation therapy. Patients who developed Phoenix-defined biochemical failure were reviewed for sites of relapse and investigations completed., Results: At a median follow-up of 5 years, 108 of 2223 patients (4.8%) developed biochemical relapse. In 1 additional patient, local relapse was found on transurethral prostate resection, but his prostate-specific antigen concentration was well short of triggering Phoenix-defined failure. Of the 109 patients with disease relapse, 18 of 2223 (0.8%) had a proven local recurrence, and 30 of 2223 (1.3%) had a proven distant recurrence. The remaining 61 of 2223 patients (2.7%) had unidentified sites of recurrence; of these, 57 patients (93%) had digital rectal examinations (DREs), 18 (30%) had post-treatment biopsies, 45 (74%) had bone scans, and 34 (56%) had computed tomography imaging of the abdomen and pelvis. If every biochemical failure were local, the local recurrence rate would be as high as 4.9%; however, by excluding those with proven distant failure and those with both a negative DRE and biopsy, we estimate that the local recurrence rate is 2.7% or less., Conclusions: In the context of limitations of the study design, our population-based analysis indicates that the local recurrence rate after LDR-PB is as low or lower than that after RP in our jurisdiction., (Copyright © 2015 Elsevier Inc. All rights reserved.) more...

Purpose: To compare the second malignancy incidence in prostate cancer patients treated with brachytherapy (BT) relative to radical prostatectomy (RP) and to compare both groups with the cancer incidence in the general population., Methods and Materials: From 1998 to 2010, 2418 patients were treated with Iodine 125 prostate BT monotherapy at the British Columbia Cancer Agency, and 4015 referred patients were treated with RP. Cancer incidence was compared with the age-matched general population using standardized incidence ratios (SIRs). Pelvic malignancies included invasive and noninvasive bladder cancer and rectal cancer. Cox multivariable analysis was performed with adjustment for covariates to determine whether treatment (RP vs BT) was associated with second malignancy risk., Results: The median age at BT was 66 years and at RP 62 years. The SIR comparing BT patients with the general population was 1.06 (95% confidence interval [CI] 0.91-1.22) for second malignancy and was 1.53 (95% CI 1.12-2.04) for pelvic malignancy. The SIR comparing RP patients with the general population was 1.11 (95% CI 0.98-1.25) for second malignancy and was 1.11 (95% CI 0.82-1.48) for pelvic malignancy. On multivariable analysis, older age (hazard ratio [HR] 1.05) and smoking (HR 1.65) were associated with increased second malignancy risk (P<.0001). Radical prostatectomy was not associated with a decreased second malignancy risk relative to BT (HR 0.90, P=.43), even when excluding patients who received postprostatectomy external beam radiation therapy (HR 1.13, P=.25). Older age (HR 1.09, P<.0001) and smoking (HR 2.17, P=.0009) were associated with increased pelvic malignancy risk. Radical prostatectomy was not associated with a decreased pelvic malignancy risk compared with BT (HR 0.57, P=.082), even when excluding postprostatectomy external beam radiation therapy patients (HR 0.87, P=.56)., Conclusions: After adjustment for covariates, BT patients did not have an increased second malignancy risk compared with RP patients. Further follow-up of this cohort is needed given the potential latency of radiation-induced malignancies., (Copyright © 2014 Elsevier Inc. All rights reserved.) more...

Purpose: To determine late urinary toxicity (>12 months) in a large cohort of uniformly treated low-dose-rate prostate brachytherapy patients., Methods and Materials: From 1998 to 2009, 2709 patients with National Comprehensive Cancer Network-defined low-risk and low-tier intermediate-risk prostate cancer were treated with Iodine 125 ((125)I) low-dose-rate prostate brachytherapy; 2011 patients with a minimum of 25 months of follow-up were included in the study. Baseline patients, treatment, implant factors, and late urinary toxicity (Radiation Therapy Oncology Group [RTOG] grading system and International Prostate Symptom Score [IPSS]) were recorded prospectively. Time to IPSS resolution, late RTOG genitourinary toxicity was examined with Kaplan-Meier and log-rank tests. Cox proportional hazards regression was done for individual covariates and multivariable models., Results: Median follow-up was 54.5 months (range, 2-13 years). Actuarial toxicity rates reached 27% and 10% (RTOG ≥2 and ≥3, respectively) at 9-13 years. Symptoms resolved quickly in the majority of patients (88% in 6-12 months). The prevalence of RTOG 0, 1, 2, 3, and 4 toxicity with a minimum of 7 years' follow-up was 70%, 21%, 6.4%, 2.3%, and 0.08%, respectively. Patients with a larger prostate volume, higher baseline IPSS, higher D90, acute toxicity, and age >70 years had more late RTOG ≥2 toxicity (all P≤.02). The IPSS resolved slower in patients with lower baseline IPSS and larger ultrasound prostate volume, those not receiving androgen deprivation therapy, and those with higher D90. The crude rate of RTOG 3 toxicity was 6%. Overall the rate of transurethral resection of the prostate was 1.9%; strictures, 2%; incontinence, 1.3%; severe symptoms, 1.8%; late catheterization, 1.3%; and hematuria, 0.8%. The majority (80%) resolved their symptoms in 6-12 months., Conclusion: Long-term urinary toxicity after brachytherapy is low. Although actuarial rates increase with longer follow-up (27% RTOG 2 and 10% RTOG 3 at 13 years), symptoms resolve relatively quickly; between 5 and 13 years' follow-up, >90% of patients have minimal urinary toxicity. Refining patient selection criteria, planning, and treatment delivery may further reduce toxicity., (Crown Copyright © 2014. Published by Elsevier Inc. All rights reserved.) more...

Purpose: To design and implement a unique training program that uses a phantom-based simulator to teach the process of prostate brachytherapy (PB) quality assurance and improve the quality of education., Methods and Materials: Trainees in our simulator program were practicing radiation oncologists, radiation oncology residents, and fellows of the American Brachytherapy Society. The program emphasized 6 core areas of quality assurance: patient selection, simulation, treatment planning, implant technique, treatment evaluation, and outcome assessment. Using the Iodine 125 ((125)I) preoperative treatment planning technique, trainees implanted their ultrasound phantoms with dummy seeds (ie, seeds with no activity). Pre- and postimplant dosimetric parameters were compared and correlated using regression analysis., Results: Thirty-one trainees successfully completed the simulator program during the period under study. The mean phantom prostate size, number of seeds used, and total activity were generally consistent between trainees. All trainees met the V100 >95% objective both before and after implantation. Regardless of the initial volume of the prostate phantom, trainees' ability to cover the target volume with at least 100% of the dose (V100) was not compromised (R=0.99 pre- and postimplant). However, the V150 had lower concordance (R=0.37) and may better reflect heterogeneity control of the implant process., Conclusions: Analysis of implants from this phantom-based simulator shows a high degree of consistency between trainees and uniformly high-quality implants with respect to parameters used in clinical practice. This training program provides a valuable educational opportunity that improves the quality of PB training and likely accelerates the learning curve inherent in PB. Prostate phantom implantation can be a valuable first step in the acquisition of the required skills to safely perform PB., (Copyright © 2014 Elsevier Inc. All rights reserved.) more...

Purpose: Optimal local management for young women with early-stage breast cancer remains controversial. This study examined 15-year outcomes among women younger than 40 years treated with breast-conserving surgery plus whole-breast radiation therapy (BCT) compared with those treated with modified radical mastectomy (MRM)., Methods and Materials: Women aged 20 to 39 years with early-stage breast cancer diagnosed between 1989 and 2003 were identified in a population-based database. Primary outcomes of breast cancer-specific survival (BCSS), overall survival (OS) and secondary outcomes of local relapse-free survival (LRFS), locoregional relapse-free survival (LRRFS), and distant relapse-free survival (DRFS) were calculated using Kaplan-Meier methods and compared between BCT and MRM cohorts using log-rank tests. A planned subgroup analysis was performed on patients considered "ideal" for BCT (ie, T1N0, negative margins and no extensive ductal carcinoma in situ) and in whom local therapy may have the largest impact on survival because of low systemic risk., Results: 965 patients were identified; 616 had BCT and 349 had MRM. The median follow-up time was 14.4 years (range, 8.4-23.3 years). Overall, 15-year rates of BCSS (76.0% vs 74.1%, P=.62), OS (74.2% vs 73.0%, P=.75), LRFS (85.4% vs 86.5%, P=.95), LRRFS (82.2% vs 81.6%, P=.61), and DRFS (74.4% vs 71.6%, P=.40) were similar between the BCT and MRM cohorts. In the "ideal" for BCT subgroup, there were 219 BCT and 67 MRM patients with a median follow-up time of 15.5 years. The 15-year BCSS (86.1% vs 82.9%, P=.57), OS (82.6% vs 82.9%, P=.89), LRFS (86.2% vs 84.2%, P=.50), LRRFS (83.1% vs 78.3%, P=.24), and DRFS (84.8% vs 79.1%, P=.17) were similar in the BCT and MRM cohorts., Conclusions: This population-based analysis with long-term follow-up confirmed that women younger than 40 years treated with BCT had similar 15-year outcomes compared with MRM. Young age alone is not a contraindication to BCT., (Copyright © 2014 Elsevier Inc. All rights reserved.) more...

Purpose: To determine (1) the prognostic utility of prostate-specific antigen (PSA) concentration at 45 to 60 months (48mPSA) after low-dose-rate prostate brachytherapy (LDR-PB); (2) the predictors of 48mPSA; and (3) the prognostic utility of directional trends between PSA levels at 24, 36, and 48 months after LDR-PB., Methods and Materials: Between 1998 and 2008, 2223 patients with low- and intermediate-risk prostate cancer received LDR-PB monotherapy. A cohort of 1434 of these patients was identified with a documented 48mPSA and no evidence of disease relapse prior to the 48mPSA. In addition, a subset of this cohort (n=585) was identified with ≥72 months of follow-up and documented PSA values at both 24 and 36 months after implantation., Results: Median follow-up time was 76 months. Eight-year Kaplan-Meier disease-free survival (DFS) rates were 100% vs 73.4% for patients with 48mPSA≤0.2 vs those with >0.2 ng/mL; 99.1% versus 53.8% for a 48mPSA threshold of ≤0.4 versus >0.4 ng/mL, respectively; and 97.3% versus 0% for a threshold of ≤1.0 versus >1.0 ng/mL, respectively. On multivariate analysis, the only factor predictive of DFS was 48mPSA (P<.0001). On subset analysis (n=585), 29 patients had a PSA rise (defined as >0.2 ng/mL) between 24 and 36 months, 24 patients had a rise between 36 and 48 months, and 11 patients had rises over both intervals. Failure rates in these patients were 52%, 79%, and 100%, respectively. On multivariate analysis, initial PSA, androgen deprivation therapy, and dose to 90% of the prostate significantly correlated with 48mPSA but together accounted for only ∼5% of its total variance., Conclusions: The 48mPSA after LDR-PB is highly predictive of long-term DFS. Patients with 48mPSA≤0.4 ng/mL had a <1% risk of disease relapse at 8 years, whereas all patients with 48mPSA>1.0 ng/mL relapsed. Consecutive PSA rises of >0.2 ng/mL from 24 to 36 months and from 36 to 48 months were also highly predictive of subsequent failure., (Copyright © 2014 Elsevier Inc. All rights reserved.) more...

Purpose: To explore whether DNA ploidy of prostate cancer cells determined from archived transrectal ultrasound-guided biopsy specimens correlates with disease-free survival., Methods and Materials: Forty-seven failures and 47 controls were selected from 1006 consecutive low- and intermediate-risk patients treated with prostate (125)I brachytherapy (July 1998-October 2003). Median follow-up was 7.5 years. Ten-year actuarial disease-free survival was 94.1%. Controls were matched using age, initial prostate-specific antigen level, clinical stage, Gleason score, use of hormone therapy, and follow-up (all P nonsignificant). Seventy-eight specimens were successfully processed; 27 control and 20 failure specimens contained more than 100 tumor cells were used for the final analysis. The Feulgen-Thionin stained cytology samples from archived paraffin blocks were used to determine the DNA ploidy of each tumor by measuring integrated optical densities., Results: The samples were divided into diploid and aneuploid tumors. Aneuploid tumors were found in 16 of 20 of the failures (80%) and 8 of 27 controls (30%). Diploid DNA patients had a significantly lower rate of disease recurrence (P=.0086) (hazard ratio [HR] 0.256). On multivariable analysis, patients with aneuploid tumors had a higher prostate-specific antigen failure rate (HR 5.13). Additionally, those with "excellent" dosimetry (V100 >90%; D90 >144 Gy) had a significantly lower recurrence rate (HR 0.25). All patients with aneuploid tumors and dosimetry classified as "nonexcellent" (V100 <90%; D90 <144 Gy) (5 of 5) had disease recurrence, compared with 40% of patients with aneuploid tumors and "excellent" dosimetry (8 of 15). In contrast, dosimetry did not affect the outcome for diploid patients., Conclusions: Using core biopsy material from archived paraffin blocks, DNA ploidy correctly classified the majority of failures and nonfailures in this study. The results suggest that DNA ploidy can be used as a useful marker for aggressiveness of localized prostate cancer. A larger study will be necessary to further confirm our hypothesis., (Crown Copyright © 2013. Published by Elsevier Inc. All rights reserved.) more...

Purpose: To evaluate the prostate-specific antigen (PSA) kinetics of PSA failure (PSAf) and PSA bounce (PSAb) after permanent (125)I prostate brachytherapy (PB)., Methods and Materials: The study included 1,006 consecutive low and "low tier" intermediate-risk patients treated with (125)I PB, with a potential minimum follow-up of 4 years. Patients who met the Phoenix definition of biochemical failure (nadir + 2 ng/mL(-1)) were identified. If the PSA subsequently fell to ≤0.5 ng/mL(-1)without intervention, this was considered a PSAb. All others were scored as true PSAf. Patient, tumor and dosimetric characteristics were compared between groups using the chi-square test and analysis of variance to evaluate factors associated with PSAf or PSAb., Results: Median follow-up was 54 months. Of the 1,006 men, 57 patients triggered the Phoenix definition of PSA failure, 32 (56%) were true PSAf, and 25 PSAb (44%). The median time to trigger nadir + 2 was 20.6 months (range, 6-36) vs. 49 mo (range, 12-83) for PSAb vs. PSAf groups (p < 0.001). The PSAb patients were significantly younger (p < 0.0001), had shorter time to reach the nadir (median 6 vs. 11.5 months, p = 0.001) and had a shorter PSA doubling time (p = 0.05). Men younger than age 70 who trigger nadir +2 PSA failure within 38 months of implant have an 80% likelihood of having PSAb and 20% chance of PSAf., Conclusions: With adequate follow-up, 44% of PSA failures by the Phoenix definition in our cohort were found to be benign PSA bounces. Our study reinforces the need for adequate follow-up when reporting PB PSA outcomes, to ensure accurate estimates of treatment efficacy and to avoid unnecessary secondary interventions., (2010. Published by Elsevier Inc. All rights reserved.) more...

Purpose: In the absence of randomized study data, institutional case series have shown brachytherapy (BT) to produce excellent biochemical control (bNED) in patients with localized prostate cancer compared with alternative curative treatments. This study was designed to overcome some of the limitations of case series studies by using a matched-pair design in patients treated contemporaneously with BT and external beam radiation therapy (EBRT) at a single institution., Methods and Materials: Six hundred one eligible patients treated between 1998 and 2001 were prospectively followed up in our institutional databases and matched on a 1:1 basis for the following known prognostic variables: prostate-specific antigen (PSA) level, Gleason score, T stage, the use and duration of neoadjuvant androgen deprivation therapy, and the percentage of positive tissue core samples. Two hundred seventy-eight perfect matches of patients (139 in each group) with low- and intermediate-risk cancer were further analyzed. bNED (Phoenix definition) was the primary endpoint. Other endpoints were toxicity, PSA kinetics, and the secondary use of androgen deprivation therapy., Results: The 5-year bNED rates were 95% (BT) and 85% (EBRT) (p < 0.001). After 7 years, the BT bNED result was unchanged, but the rate in EBRT patients had fallen to 75%. The median posttreatment PSA nadirs were 0.04 ng/mL (BT) and 0.62 ng/mL (EBRT, p < 0.001), which predicted a higher ongoing treatment failure rate in association with EBRT use than with BT use. Late urinary toxicity and rectal/bowel toxicity were worse in patients treated with BT and EBRT, respectively., Conclusions: BT for both low-risk and selected intermediate-risk cancers achieves exceptional cure rates. Even with dose escalation, it will be difficult for EBRT to match the proven track record of BT seen over the past decade. more...

Purpose: To describe the late transient worsening of urinary symptoms ("urinary symptom flare") in 712 consecutive prostate brachytherapy patients, associated predictive factors, association with rectal and urinary toxicity, and the development of erectile dysfunction., Methods and Materials: Patients underwent implantation between 1998 and 2003 (median follow-up, 57 months). International Prostate Symptom Score (IPSS), Radiation Therapy Oncology Group (RTOG) toxicity, and erectile function data were prospectively collected. Flare was defined as an increase in IPSS of > or =5 and of > or =8 points greater than the post-treatment nadir. The relationships between the occurrence of flare and the patient, tumor, and treatment characteristics were examined. The Cox proportional hazards method was used to test individual variables and the multivariate models., Results: The incidence of flare was 52% and 30% using the flare definition of an IPSS of > or =5 and > or =8 points greater than the postimplant nadir, respectively. Of the patients with symptoms, 65% had resolution of their symptoms within 6 months and 91% within 1 year. Flares most commonly occurred 16-24 months after implantation. On multivariate analysis, a greater baseline IPSS and greater maximal postimplant IPSS were the predictors of flare, regardless of the flare definition used. Androgen suppression was a predictor for fewer flares (IPSS > or =5). Diabetes and prostate edema predicted for more frequent flares (IPSS >/=8). Patients with flare had a greater incidence of RTOG Grade 3 urinary toxicity and RTOG Grade 2 or greater rectal toxicity. No association was found between erectile dysfunction and the occurrence of flare., Conclusion: Urinary symptom flare is a common, transient phenomenon after prostate brachytherapy. A greater baseline IPSS and maximal postimplant IPSS were the strongest predictive factors. Flare was associated with a greater incidence of late RTOG Grade 3 urinary toxicity and greater rate of late RTOG Grade 2 or greater rectal toxicity. more...

Purpose: To analyze dosimetric outcomes after permanent brachytherapy for men with low-risk and "low-tier" intermediate-risk prostate cancer and explore the relationship between the traditional dosimetric values, V100 (volume of prostate receiving 100% of the prescribed dose) and D90 (minimum dose to 90% of the prostate), and risk of biochemical failure., Methods and Materials: A total of 1,006 consecutive patients underwent implantation between July 20, 1998, and Oct 23, 2003. Most (58%) had low-risk disease; the remaining 42% comprised a selected low-tier subgroup of intermediate-risk patients. The prescribed minimum peripheral dose (MPD) was 144 Gy. All implants used 0.33 mCi 125I sources using a preplan technique featuring right-left symmetry and a strong posterior-peripheral dose bias. Sixty-five percent of patients had 6 months of androgen deprivation therapy. Postimplantation dosimetry was calculated using day-28 CT scans., Results: With a median follow-up of 54 months, the actuarial 5-year rate of freedom from biochemical recurrence (bNED) was 95.6% +/- 1.6%. Median D90 was 105% of MPD, median V100 was 92%, median V150 was 58%, and median V200 was 9%. Dosimetric values were not predictive of biochemical recurrence on univariate or multivariate analysis. Analysis of dosimetric values by implantation number showed statistically significant increases in all values with time (D90, V100, V150, and V200; p < 0.001), but this did not translate into improved bNED., Conclusions: In contrast to some previous studies, dosimetric outcomes did not correlate with biochemical recurrence in the first 1,006 patients treated with 125I prostate brachytherapy at the British Columbia Cancer Agency. Despite a median D90 of only 105% of MPD, our bNED rates are indistinguishable from series that reported higher D90 values. more...

Purpose: To describe the frequency of acute and late Radiation Therapy Oncology Group (RTOG) urinary toxicity, associated predictive factors, and resolution of International Prostate Symptom Score (IPSS) in 712 consecutive prostate brachytherapy patients., Methods and Materials: Patients underwent implantation between 1998 and 2003 (median follow-up, 57 months). The IPSS and RTOG toxicity data were prospectively collected. The patient, treatment, and implant factors were examined for an association with urinary toxicity. The time to IPSS resolution was examined using Kaplan-Meier curves, and multivariate modeling of IPSS resolution was done using Cox proportional hazards regression analysis. Logistic regression analysis was used to examine the factors associated with urinary toxicity., Results: The IPSS returned to baseline at a median of 12.6 months. On multivariate analysis, patients with a high baseline IPSS had a quicker resolution of their IPSS. Higher prostate D90 (dose covering 90% of the prostate), maximal postimplant IPSS, and urinary retention slowed the IPSS resolution time. The rate of the actuarial 5-year late urinary (>12 months) RTOG Grade 0, 1, 2, 3, and 4 was 32%, 36%, 24%, 6.2%, and 0.1%, respectively. At 7 years, the prevalence of RTOG Grade 0-1 was 92.5%. Patients with a larger prostate volume, greater number of needles, greater baseline IPSS, and use of hormonal therapy had more acute toxicity. On multivariate analysis, the significant predictors for late greater than or equal to RTOG toxicity 2 were a greater baseline IPSS, maximal postimplant IPSS, presence of acute toxicity, and higher prostate V150 (volume of the prostate covered by 150% of the dose). More recently implanted patients had less acute urinary toxicity and patients given hormonal therapy had less late urinary toxicity (all p < 0.02)., Conclusion: Most urinary symptoms resolved within 12 months after prostate brachytherapy, and significant long-term urinary toxicity was very low. Refined patient selection and greater technical experience in prostate brachytherapy were associated with less urinary toxicity. more...

Purpose: To determine whether segmental urethral dosimetry is predictive for the degree of urinary morbidity after prostate brachytherapy in patients with no urinary symptoms before prostate brachytherapy., Methods and Materials: Between May 2000 and November 2005, 1,107 patients underwent iodine-125 monotherapy with urethral sparing techniques. A total of 166 patients fulfilled the selection criteria: baseline (International Prostate Symptom Score) IPSS < or =5, no androgen deprivation therapy, and prostate ultrasound planning volumes (PUTV) <45 mL. The median follow-up was 44 months. Urinary morbidity was defined by maximum increase in IPSS, time to IPSS resolution, maximum Radiation Therapy Oncology Group (RTOG) score, time to RTOG resolution, and urinary retention. Surrogate deviated urethra was contoured and doses calculated at the base, mid-prostate, apex, and urogenital diaphragm. Univariate and multivariate analysis was used to evaluate urethral and prostate dosimetry, age, PUTV, and number of needles for their association with urinary morbidity., Results: Urethral dose was fairly constant in all urethra segments except prostate base, where the variation in does was large. On multivariate analysis, higher urethral base D50, V100, and larger PUTV were predictive for higher maximum increase in IPSS. Higher urethral base V100 and larger PUTV predicted for prolonged IPSS resolution. Higher urethral base D50 and larger needle number predicted for longer RTOG resolution. Higher urethral base V100 predicted for RTOG > or =2 toxicity., Conclusions: Radiation dose to the urethral base, larger PUTV, and needle number, predicted for increased urinary toxicity after prostate brachytherapy. Correlation between urinary morbidity and urethral base dosimetry may reflect a large variation in urethral dose observed at the prostate base. more...

Purpose: To examine whether modified radical mastectomy (MRM) improves outcomes compared with breast-conserving treatment (BCT) in young women., Methods and Materials: Women aged 20-49 years, diagnosed with early breast cancer between 1989 and 1998, were identified. Management with BCT or MRM was compared for local (L), locoregional (LR), and distant relapse-free survival (DRFS) and breast cancer-specific survival (BCSS) by age group (20-39 years, 40-49 years). The analysis was repeated for patients considered "ideal" candidates for BCT: tumor size < or =2 cm, pathologically negative axillary nodes, negative margins, and no reported ductal carcinoma in situ., Results: A total of 1,597 women received BCT, and 801 had MRM. After a median follow-up of 9.0 years, the outcomes (L, LR, BCSS) were worse for the younger age group; however, the outcomes were not statistically different by type of local treatment. For women aged 20-39 years considered "ideal" for BCT, those treated with BCT had slightly lower LRFS compared with those treated with MRM (p = 0.3), but DRFS and BCSS were similar., Conclusions: A difference in LRFS at 10 years potentially favored MRM among women aged 20-39 years considered "ideal" BCT candidates but was not statistically significant and did not translate into a noticeable difference in DRFS or BCSS. Our data suggest that young age alone is not a contraindication to BCT. more...

Purpose: To evaluate the incidence and factors predictive of acute urinary retention (AUR) in 805 consecutive patients treated with prostate brachytherapy monotherapy and to examine the possible effect of a learning curve., Methods and Materials: Between July 1998 and November 2002, 805 patients were treated with prostate brachytherapy. Low-risk patients (Gleason Score (GS) < or = 6; prostate specific antigen (PSA) < or = 10, and < or = T2b [UICC 1997]) received implant alone. Patients with prostate volume of 50 cc or more, GS = 7, or PSA = 10 to 15 received 6 months of androgen suppression (AS) with brachytherapy. Patient, treatment, and dosimetric factors examined include baseline prostate symptom score (IPSS), diabetes, vascular disease, PSA, Gleason score, clinical stage, AS, ultrasound planning target volume (PUTV), postimplant prostate volume (obtained with "Day 30" postimplant CT), CT:PUTV ratio (surrogate for postimplant edema), number of seeds, number of needles, number of seeds per needle, dosimetric parameters (V100, V150, and D90), date of implant (learning curve), and implanting oncologists. Univariate and multivariate analyses were carried out., Results: Acute urinary retention in the first 200 patients was 17% vs. 6.3% in the most recently treated 200 patients (p = 0.002). Overall AUR was 12.7%, and prolonged urinary obstruction incidence (> 20 days) was 5%. On multivariate analysis, factors predictive of any AUR include baseline IPSS (p = < 0.004), CT:PUTV ratio (p = < 0.001), PUTV (p = < 0.001), and implant order (learning curve) (p = 0.001). Factors predictive for "prolonged" catheterization (> 20 days) on multivariate analysis include IPSS (p < 0.01), number of needles (p < 0.001), diabetes mellitus (p = 0.048), and CT:PUTV ratio (p < 0.001), Conclusion: Over the years, our AUR rate has fallen significantly (from 17% to 6.3%). On multivariate analysis, highly significant factors include IPSS, PUTV, CT:PUTV ratio (i.e., degree of prostate edema), and order of implant (learning curve). Over the course of the program, we have deliberately reduced the number of needles and OR time per patient, which have potentially minimized intraoperative trauma and may have contributed to less toxicity. A learning curve in prostate brachytherapy programs affect not only the outcome but also the toxicity from the treatment. more...

Purpose: To determine predictive factors for postimplant erectile dysfunction (ED) in a cohort of patients, according to prospectively collected data; specifically, to assess the impact of penile bulb volume and D50 and D95 (dose covering 50% and 95% of the penile bulb volume, respectively) on ED., Methods and Materials: Three hundred forty-two patients were identified who were potent before implant and who had at least 2 years' follow-up. Patient, tumor, treatment, and dosimetric data were collected on all patients. Postimplant ED was defined according to both physician-documented and patient-documented outcome data. Binary logistic regression analysis was used to create multivariable models of predictors for ED at 1, 2, and 3 years after implant., Results: Physician-documented rates of ED were 57%, 48%, and 38% at 1, 2, and 3 years after implant, respectively. Patient-documented rates of ED were 70% and 66% at 1 and 2 years, respectively. Multivariable analyses revealed age and degree of pre-implant erectile function to be consistently significant predictors of ED. Use of hormones was significant at the 1-year physician-documented ED endpoint but not thereafter, in keeping with the time course of testosterone recovery. Penile bulb volume, D50, and D95 were not found to be predictive for ED at any time point, in contrast to previous studies. In addition, planning ultrasound target volume, number of needles, and institutional case sequence number were significant predictors of ED at various time points, consistent with a traumatic etiology of ED., Conclusions: We found no evidence to support penile bulb dosimetry as an independent predictive factor for ED after implant, using physician-documented or patient-documented outcomes. more...

Purpose: Radiation oncology's popularity as a career in Canada has surged in the past 5 years. Consequently, resident numbers in Canadian radiation oncology residencies are at all-time highs. This study aimed to survey Canadian radiation oncology residents about their opinions of their specialty and training experiences., Methods and Materials: Residents of Canadian radiation oncology residencies that enroll trainees through the Canadian Resident Matching Service were identified from a national database. Residents were mailed an anonymous survey., Results: Eight of 101 (7.9%) potential respondents were foreign funded. Fifty-two of 101 (51.5%) residents responded. A strong record of graduating its residents was the most important factor residents considered when choosing programs. Satisfaction with their program was expressed by 92.3% of respondents, and 94.3% expressed satisfaction with their specialty. Respondents planning to practice in Canada totaled 80.8%, and 76.9% plan to have academic careers. Respondents identified job availability and receiving adequate teaching from preceptors during residency as their most important concerns., Conclusions: Though most respondents are satisfied with their programs and specialty, job availability and adequate teaching are concerns. In the future, limited time and resources and the continued popularity of radiation oncology as a career will magnify the challenge of training competent radiation oncologists in Canada. more...

Purpose: To determine the relationship between prostate-specific antigen (PSA) failure and cause-specific and overall survival in prostate cancer patients treated with radical radiotherapy., Methods and Materials: Patients with and without PSA failure were compared with respect to overall survival and cause-specific survival in a cohort of 1786 patients. The relationship between PSA failure and survival was further investigated among six subgroups defined by three tumor risk groups (high, intermediate, and low risk based on T stage, Gleason score, and presenting PSA) and two age groups (<75 years and >/=75 years)., Results: The 5-year overall survival among patients who had PSA failure was 79.5% vs. 87.5% among patients who had not failed (p = 0.0003). The corresponding 5-year cause-specific survival was 84.4% vs. 99.0% (p <0.0001). When the six subgroups are considered separately, PSA failure was associated with a worse cause-specific survival in the groups with intermediate- and high-risk disease. PSA failure was only associated with a worse overall survival in one subgroup: patients younger than 75 with high-risk disease. Deaths from nonprostate causes made the survival curves of patients with and without PSA failure in the other subgroups almost identical., Conclusion: PSA failure in prostate cancer patients treated with radiotherapy was associated with a poorer overall survival, which is seen mainly in younger patients with high-risk disease. more...

Purpose: In this case report, we describe 7 patients with suboptimal dosimetry after (125)I prostate brachytherapy who underwent a second implant procedure to improve the dosimetric coverage of the prostate., Methods and Materials: Seven patients underwent second (125)I implants for suboptimal dosimetry after their initial implant for prostate cancer. The pretreatment characteristics (clinical stage, Gleason score, initial prostate-specific antigen level, location of positive cores, International Prostate Symptom Score, potency, use of androgen suppression, initial implant planning characteristics) were noted. The "Day 30" CT-based dosimetry parameters after the first implant and "Day 0" CT-based dosimetry after the reimplant were recorded (volumes of prostate and rectum covered by 100% and 150% of the dose and dose covering 90% of the prostate volume). The toxicity of the second procedure, International Prostate Symptom Scores before and after reimplantation, the clinical course, and prostate-specific antigen outcomes after reimplant were examined. We described our reimplant planning and intraoperative procedure., Results: In all 7 patients, we were able to achieve very favorable dosimetry after the second procedure. The acute toxicity of the reimplant procedure was reasonably low, and the short-term prostate-specific antigen outcome has been favorable., Conclusion: It is possible to add more seeds safely to the dosimetrically cool area after the initial brachytherapy procedure and achieve excellent postimplant dosimetry with acceptable acute toxicity. The ultimate benefits and long-term toxicity of reimplantation are unknown. more...

Purpose: To evaluate the late toxicity profile of prostate cancer patients treated with external beam radiotherapy, to investigate the possible risk factors for late toxicity, and to determine whether neoadjuvant androgen ablation (NAA) is a factor., Methods and Materials: The study population consisted of 1192 patients with > or =24 months' follow-up. Late GI and GU toxicities were scored with a modified Radiation Therapy Oncology Group/Subjective, Objective, Management, and Analytic scale. All patients were treated with external beam radiotherapy (52.5 Gy in 20 fractions to 72 Gy in 36 fractions), using either conventional or three-dimensional conformal techniques. Of the 1192 patients, 40% received NAA (median 5 months). Risk factors investigated on multivariate analysis were age, past medical history, use of pelvic fields, dose, fractionation, use and duration of neo- and adjuvant androgen ablation, and acute toxicity (Grade 2 or greater)., Results: The median follow-up for the group was 49 months (range 24-105). The incidence of late Grade 2-3 GI or GU toxicity was 30% at 5 years (GI 12% and GU 20%). The incidence of late Grade 3 GI or GU toxicity was 8% at 5 years (GI 2.7% and GU 5.5%). No Grade 4 toxicity occurred. The risk factors of significance in relation to the development of late Grade 3 GU toxicity were coexisting GU disease (p = 0.02), prior transurethral resection of the prostate or transurethral resection of bladder tumor (p <0.0001), and presence of acute GU toxicity (p = 0.012). For late Grade 3 GI toxicity, short-term (< or =2 months) NAA (p = 0.0002) and coexisting GI disease (p = 0.017) were risk factors., Conclusion: Short-term (< or =2 months) NAA, but not longer durations of NAA, increases the risk of developing Grade 3 GI late toxicity. The possible mechanism of this phenomenon is unclear. more...

Purpose: To assess and compare two models for a surrogate urethra to be used for postimplant dosimetry in prostate brachytherapy., Methods and Materials: Twenty men with a urinary catheter present at the time of postimplant computed tomographic imaging were studied. Urethral and periurethral volumes were defined as 5-mm and 10-mm diameter volumes, respectively. Three contours of each were used: one contour of the true urethra (and periurethra), and two surrogate models. The true volumes were centered on the catheter center. One surrogate model used volumes centered on the geometrical center of each prostate contour (centered surrogate). The other surrogate model was based on the average deviation of the true urethra from a reference line through the geometrical center of the axial midplane of the prostate (deviated surrogate). Maximum point doses and the D(10), D(25), D(50), D(90), V(100), V(120), and V(150) of the true and surrogate volumes were measured and compared (D(n) is the minimum dose [Gy] received by n% of the structure, and V(m) is the volume [%] of the structure that received m% of the prescribed dose) as well as the distances between the surrogate urethras and the true urethra., Results: Doses determined from both surrogate urethral and periurethral volumes were in good agreement with the true urethral and periurethral doses except in the superior third of the gland. The deviated surrogate provided a physically superior likeness to the true urethra. Certain dose-volume histogram (DVH)-based parameters could also be predicted reasonably well on the basis of the surrogates. Correlation coefficients > or =0.85 were seen for D(25), D(50), V(100), V(120), and V(150) for both models. All the other parameters had correlation coefficients in the range of 0.73 - 0.85., Conclusions: Both surrogate models predicted true urethral dosimetry reasonably well. It is recommended that the simpler deviated surrogate would be a more suitable surrogate for routine clinical practice. more...

Purpose: To compare several different methods of calculating the rectal dose and examine how accurately they represent rectal dose surface area measurements and, also, their practicality for routine use., Methods and Materials: This study comprised 55 patients, randomly selected from 295 prostate brachytherapy patients implanted at the Vancouver Cancer Center between 1998 and 2000. All implants used a nonuniform loading of 0.33 mCi (NIST-99) 125I seeds and a prescribed dose of 144 Gy. Pelvic CT scans were obtained for each patient approximately 30 days after implantation. For the purposes of calculating the rectal dose, several structures were contoured on the CT images: (1) a 1-mm-thick anterior rectal wall, (2) the anterior half rectum, and (3) the whole rectum. Point doses were also obtained along the anterior rectal surface. The thin wall contour provided a surrogate for a dose-surface histogram (DSH) and was our reference standard rectal dose measurement. Alternate rectal dose measurements (volume, surface area, and length of rectum receiving a dose of interest [DOI] of > or =144 Gy and 216 Gy, as well as point dose measures) were calculated using several methods (VariSeed software) and compared with the surrogate DSH measure (SA(DOI))., Results: The best correlation with SA(144 Gy) was the dose volumes (whole or anterior half rectum) (R = 0.949). The length of rectum receiving > or =144 Gy also correlated well with SA(144 Gy) (R > or =0.898). Point dose measures, such as the average and maximal anterior dose, correlated poorly with SA(144 Gy) (R < or =0.649). The 216-Gy measurements supported these results. In addition, dose-volume measurements were the most practical (approximately 6 min/patient), with our surrogate DSH the least practical (approximately 20 min/patient)., Conclusion: Dose-volume measurements for the whole or anterior half rectum, because they were the most practical measures and best represented the DSH measurements, should be considered a standard method of reporting the rectal dose when calculating the DSH is not practical. Average or maximal anterior rectal doses are not reliable indicators of surface area dosimetry. more...

Purpose: To evaluate the incidence and duration of urinary retention requiring catheterization and the factors predictive for these end points., Methods and Materials: Two hundred eighty-two patients treated with prostate brachytherapy alone were evaluated. Clinical and treatment-related factors examined included: age, baseline International Prostate Symptom Score (IPSS), presence of comorbidity, planning ultrasound target volume (PUTV), postimplant prostate CT scan volume, the CT:PUTV ratio, number of seeds inserted, number of needles used, use of neoadjuvant hormones, procedural physician, clinical stage, Gleason score, and pretreatment PSA. Dosimetric quality indicators were also examined., Results: Urinary obstruction after prostate brachytherapy developed in 43 (15%) patients. The median duration of catheter insertion was 21 days (mean 49, range 1-365). Univariate analysis demonstrated that presence of diabetes, preimplant volume, postimplant volume, CT:PUTV ratio, number of needles, and dosimetric parameters were predictive for catheterization. However, in multivariate analysis, only the baseline IPSS, CT:PUTV ratio, and presence of diabetes were significant independent predictive factors for catheterization., Conclusion: Baseline IPSS was the most important predictive factor for postimplantation catheterization. The extent of postimplant edema, as reflected by the CT:PUTV ratio, predicted for need and duration of catheterization. The presence of diabetes was predictive for catheterization, but may relate to the absence of prophylactic steroids, and therefore requires further evaluation. more...

Purpose: To investigate postimplant dosimetry for different regions of the prostate gland in patients treated with transperineal 125Iodine brachytherapy implants for low- and intermediate-risk prostate cancer., Methods and Materials: Two hundred eighty-four patients treated with permanent interstitial prostate brachytherapy comprised the study population. A nonuniform, urethral-sparing algorithm was used to plan all patients. Prostate contours were outlined on postimplant CT images. Prostate volumes were then divided into four quadrants: anterior-superior quadrant (ASQ), posterior-superior quadrant (PSQ), anterior-inferior quadrant (AIQ), and posterior-inferior quadrant (PIQ). Dose-volume histograms (DVHs) were calculated for the whole prostate and each quadrant., Results: The mean postimplant V(100) +/- 95% confidence (the percent prostate volume encompassed within the isodose surface comprising the prescription dose = 144 Gy) for the ASQ was 78.5 +/- 1.9, which was significantly lower than that of the PSQ, AIQ, and PIQ in which the V(100) plus minus 95% confidence values were 94.9 +/- 0.8, 92.6 +/- 1.2, and 98.7 +/- 0.3, respectively. The mean V(100) +/- 95% confidence for the whole prostate was 90.4 +/- 0.8. Mean values for V(150) and D(90) (the minimum dose in Gy received by 90% of the target volume) for the four quadrants and the whole prostate showed similar results., Conclusions: Underdosed areas of the planning target volume (PTV), if present, were largely confined to the ASQ, which received a significantly lower dose, on average, compared to the other three quadrants of the prostate. more...