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BACKGROUND Using a prospectively collected institutional database, we compared rectal toxicity following high dose rate (HDR) brachytherapy as monotherapy relative to dose-escalated external beam radiotherapy (EBRT) for patients with localized prostate cancer. METHODS 2683 patients treated with HDR or EBRT between 1994 and 2017 were included. HDR fractionation was 38 Gy/4 fractions (n = 321), 24 Gy/2 (n = 96), or 27 Gy/2 (n = 128). EBRT patients received a median dose of 75.6 Gy in 1.8 Gy fractions [range 70.2-82.8 Gy], using either 3D conformal or intensity modulated radiotherapy (IMRT). EBRT patients underwent 3D image guidance via an off-line adaptive process. RESULTS Median follow-up was 7.5 years (7.4 years for EBRT and 7.9 years for HDR). 545 patients (20.3%) received HDR brachytherapy and 2138 (79.7%) EBRT. 69.1% of EBRT patients received IMRT. Compared to EBRT, HDR was associated with decreased rates of acute grade ≥2 diarrhea (0.7% vs. 4.5%, p

Purpose To report outcomes for ductal carcinoma in situ (DCIS) treated with breast-conserving therapy using accelerated partial breast irradiation (APBI). Methods and Materials From March 2001 to February 2009, 53 patients with Stage 0 breast cancer were treated with breast conserving surgery and adjuvant APBI. Median age was 62 years. All patients underwent excision with margins negative by ≥1 mm before adjuvant radiotherapy (RT). A total of 39 MammoSite brachytherapy (MS) patients and 14 three-dimensional conformal external beam RT (3DCRT) patients were treated to the lumpectomy bed alone with 34 Gy and 38.5 Gy, respectively. Of the DCIS cases, 94% were mammographically detected. All patients with calcifications had either specimen radiography or postsurgical mammography confirmation of clearance. Median tumor size was 6 mm, and median margin distance was 5 mm. There were no statistically significant differences according to APBI method for race/ethnicity, tumor detection method, tumor grade, estrogen receptor (ER) status, or use of tamoxifen ( p = NS). Recurrence and survival were calculated using the Kaplan–Meier method. Cosmesis was scored by the Harvard criteria. Results With a median follow-up of 3.6 years (range, 0.4–6.3 years), the overall and cause-specific survival rates were 98% and 100%, respectively. Three-year actuarial ipsilateral breast tumor recurrence was 2%. One failure was observed at the resection bed 11 months post-RT. No other elsewhere breast failures, regional recurrences, or distant metastases were noted. Cosmesis was excellent or good in 92.4% of cases, with no statistically significant differences according to the APBI method (92.3% with MammoSite and 92.8% with 3DCRT; p = 0.649). Conclusions APBI as part of breast-conserving therapy for pure DCIS was associated with excellent local control and survival rates, with the vast majority of patients having good to excellent cosmesis. This finding supports the recent analysis by the American Society of Breast Surgeons on a subset of DCIS patients treated efficaciously with APBI.

The radiobiology of prostate cancer appears to favor large fractions. Accelerated hypofractionation treatments may therefore be used to improve the therapeutic ratio, particularly when the doses to rectum and bladder are kept below the prostate dose. The 5-year experience at William Beaumont Hospital (WBH) and the California Endocurietherapy Center (CET) with accelerated-hypofractionated high-dose-rate (HDR) monotherapy in favorable prostate cancer is presented.Between 1993 and 2004, 454 patients were treated with brachytherapy of which 248 treated with HDR and 206 patients treated with low-dose-rate Palladium (LDR-Pd¹⁰³). The WBH-HDR dose was 38 Gy, in 4 fractions, twice a day. The CET-HDR dose was 42 Gy in 6 fractions in 2 separate implants 1 week apart. The WBH-LDR dose was 120 Gy.Median follow-up was 4.8 years. The 5-year Phoenix biochemical control (BC) was 89%, 91%, and 88% for WBH-LDR, WBH- HDR, and CET-HDR, respectively. The majority of complications were grade 1. HDR was associated with less acute grade 1 to 3 dysuria 60% versus 39%, (P0.001), urinary frequency/urgency 90% to58% (P0.001), and rectal pain 17% to 6.5% (P0.001). Long-term urinary frequency/urgency 54% versus 43%, (P = 0.03) and dysuria 22% versus 15% were less with HDR. The 5-year actuarial impotence rate was 30% for LDR and 20% for HDR (P = 0.23).Although the same 5-year BC rates were achieved with HDR (248 patients) and LDR (206 patients) monotherapy, HDR brachytherapy was associated with less acute and chronic genitourinary and gastrointestinal toxicities. As another accepted standard of care, accelerated hypofractionated HDR monotherapy is target specific and efficient radiobiologically than EBRT which has many smaller doses per fraction. It could be considered today as the best option in accelerated hypofractionated prostate cancer treatment.

Purpose: We performed a complete pathologic analysis examining extracapsular extension (ECE) and microscopic spread of malignant cells beyond the prostate capsule to determine whether and when clinical target volume (CTV) expansion should be performed. Methods and Materials: A detailed pathologic analysis was performed for 371 prostatectomy specimens. All slides from each case were reviewed by a single pathologist (N.S.G.). The ECE status and ECE distance, defined as the maximal linear radial distance of malignant cells beyond the capsule, were recorded. Results: A total of 121 patients (33%) were found to have ECE (68 unilateral, 53 bilateral). Median ECE distance = 2.4 mm [range: 0.05–7.0 mm]. The 90th-percentile distance = 5.0 mm. Of the 121 cases with ECE, 55% had ECE distance ≥2 mm, 19% ≥4 mm, and 6% ≥6 mm. ECE occurred primarily posterolaterally along the neurovascular bundle in all cases. Pretreatment prostrate-specific antigen (PSA), biopsy Gleason, pathologic Gleason, clinical stage, bilateral involvement, positive margins, percentage of gland involved, and maximal tumor dimension were associated with presence of ECE. Both PSA and Gleason score were associated with ECE distance. In all 371 patients, for those with either pretreatment PSA ≥10 or biopsy Gleason score ≥7, 21% had ECE ≥2 mm and 5% ≥4 mm beyond the capsule. For patients with both of these risk factors, 49% had ECE ≥2 mm and 21% ≥4 mm. Conclusions: For prostate cancer with ECE, the median linear distance of ECE was 2.4 mm and occurred primarily posterolaterally. Although only 5% of patients demonstrate ECE >4 to 5 mm beyond the capsule, this risk may exceed 20% in patients with PSA ≥10 ng/ml and biopsy Gleason score ≥7. As imaging techniques improve for prostate capsule delineation and as radiotherapy delivery techniques increase in accuracy, a posterolateral CTV expansion should be considered for patients at high risk.

To quantify the theoretical benefit, in terms of improvement in precision and accuracy of treatment delivery and in dose increase, of using online image-guided intensity-modulated radiotherapy (IG-IMRT) performed with onboard cone-beam computed tomography (CT), in an ideal setting of no intrafraction motion/deformation, in the treatment of prostate cancer.Twenty-two prostate cancer patients treated with conventional radiotherapy underwent multiple serial CT scans (median 18 scans per patient) during their treatment. We assumed that these data sets were equivalent to image sets obtainable by an onboard cone-beam CT. Each patient treatment was simulated with conventional IMRT and online IG-IMRT separately. The conventional IMRT plan was generated on the basis of pretreatment CT, with a clinical target volume to planning target volume (CTV-to-PTV) margin of 1 cm, and the online IG-IMRT plan was created before each treatment fraction on the basis of the CT scan of the day, without CTV-to-PTV margin. The inverse planning process was similar for both conventional IMRT and online IG-IMRT. Treatment dose for each organ of interest was quantified, including patient daily setup error and internal organ motion/deformation. We used generalized equivalent uniform dose (EUD) to compare the two approaches. The generalized EUD (percentage) of each organ of interest was scaled relative to the prescription dose at treatment isocenter for evaluation and comparison. On the basis of bladder wall and rectal wall EUD, a dose-escalation coefficient was calculated, representing the potential increment of the treatment dose achievable with online IG-IMRT as compared with conventional IMRT.With respect to radiosensitive tumor, the average EUD for the target (prostate plus seminal vesicles) was 96.8% for conventional IMRT and 98.9% for online IG-IMRT, with standard deviations (SDs) of 5.6% and 0.7%, respectively (p0.0001). The average EUDs of bladder wall and rectal wall for conventional IMRT vs. online IG-IMRT were 70.1% vs. 47.3%, and 79.4% vs. 72.2%, respectively. On average, a target dose increase of 13% (SD = 9.7%) can be achieved with online IG-IMRT based on rectal wall EUDs and 53.3% (SD = 15.3%) based on bladder wall EUDs. However, the variation (SD = 9.7%) is fairly large among patients; 27% of patients had only minimal benefit (5% of dose increment) from online IG-IMRT, and 32% had significant benefit (15%-41% of dose increment).The ideal maximum dose increment achievable with online IG-IMRT is, on average, 13% with respect to the dose-limiting organ of rectum. However, there is a large interpatient variation, ranging5%-41%. The results can be applied to calibrate other practical online image-guided techniques for prostate cancer radiotherapy, when intratreatment organ motion/deformation and machine delivery accuracy are considered.

Purpose To report the toxicity profile of high-dose-rate (HDR)-brachytherapy (BT) as monotherapy in a Human Investigation Committee-approved study consisting of a single implant and two fractions (12 Gy × 2) for a total dose of 24 Gy, delivered within 1 day. The dose was subsequently increased to 27 Gy (13.5 Gy × 2) delivered in 1 day. We report the acute and early chronic genitourinary and gastrointestinal toxicity. Methods and Materials A total of 173 patients were treated between December 2005 and July 2010. However, only the first 100 were part of the IRB-approved study and out of these, only 94 had a minimal follow-up of 6 months, representing the study population for this preliminary report. All patients had clinical Stage T2b or less (American Joint Committee on Cancer, 5th edition), Gleason score 6-7 (3+4), and prostate-specific antigen level of ≤12 ng/mL. Ultrasound-guided HDR-BT with real-time dosimetry was used. The prescription dose was 24 Gy for the first 50 patients and 27 Gy thereafter. The dosimetric goals and constraints were the same for the two dose groups. Toxicity was scored using the National Cancer Institute Common Terminology Criteria for Adverse Events, version 3. The highest toxicity scores encountered at any point during follow-up are reported. Results The median follow-up was 17 months (range, 6–40.5). Most patients had Grade 0-1 acute toxicity. The Grade 2 acute genitourinary toxicity was mainly frequency/urgency (13%), dysuria (5%), hematuria, and dribbling/hesitancy (2%). None of the patients required a Foley catheter at any time; however, 8% of the patients experienced transient Grade 1 diarrhea. No other acute gastrointestinal toxicities were found. The most common chronic toxicity was Grade 2 urinary frequency/urgency in 16% of patients followed by dysuria in 4% of patients; 2 patients had Grade 2 rectal bleeding and 1 had Grade 4, requiring laser treatment. Conclusions Favorable-risk prostate cancer patients treated with a single implant HDR-BT to 24–27 Gy in two fractions within 1 day have excellent tolerance with minimal acute and chronic toxicity. Longer follow-up is needed to confirm these encouraging early results.

Purpose High-dose-rate (HDR) brachytherapy used as the only treatment (monotherapy) for early prostate cancer is consistent with current concepts in prostate radiobiology, and the dose is reliably delivered in a prospectively defined anatomic distribution that meets all the requirements for safe and effective therapy. We report the disease control and toxicity of HDR monotherapy from California Endocurietherapy (CET) and William Beaumont Hospital (WBH) in low- and intermediate-risk prostate cancer patients. Methods and Materials There were 298 patients with localized prostate cancer treated with HDR monotherapy between 1996 and 2005. Two biologically equivalent hypofractionation protocols were used. At CET the dose was 42 Gy in six fractions (two implantations 1 week apart) delivered to a computed tomography–defined planning treatment volume. At WBH the dose was 38 Gy in four fractions (one implantation) based on intraoperative transrectal ultrasound real-time treatment planning. The bladder, urethral, and rectal dose constraints were similar. Toxicity was scored with the National Cancer Institute Common Toxicity Criteria for Adverse Events version 3. Results The median follow-up time was 5.2 years. The median age of the patients was 63 years, and the median value of the pretreatment prostate-specific antigen was 6.0 ng/mL. The 8-year results were 99% local control, 97% biochemical control (nadir +2), 99% distant metastasis–free survival, 99% cause-specific survival, and 95% overall survival. Toxicity was scored per event, meaning that an individual patient with more than one symptom was represented repeatedly in the morbidity data table. Genitourinary toxicity consisted of 10% transient Grade 2 urinary frequency or urgency and 3% Grade 3 episode of urinary retention. Gastrointestinal toxicity was Conclusions High disease control rates and low morbidity demonstrate that HDR monotherapy is safe and effective for patients with localized prostate cancer.

Purpose Assessment of androgen deprivation therapy (ADT) benefits for prostate cancer treated with dose-escalated radiotherapy (RT). Methods and Materials From 1991 to 2004, 1,044 patients with intermediate- ( n = 782) or high-risk ( n = 262) prostate cancer were treated with dose-escalated RT at William Beaumont Hospital. Patients received external-beam RT (EBRT) alone, brachytherapy (high or low dose rate), or high dose rate brachytherapy plus pelvic EBRT. Intermediate-risk patients had Gleason score 7, prostate-specific antigen (PSA) 10.0–19.9 ng/mL, or Stage T2b–T2c. High-risk patients had Gleason score 8–10, PSA ≥20, or Stage T3. Patients were additionally divided specifically by Gleason score, presence of palpable disease, and PSA level to further define subgroups benefitting from ADT. Results Median follow-up was 5 years; 420 patients received ADT + dose-escalated RT, and 624 received dose-escalated RT alone. For all patients, no advantages in any clinical endpoints at 8 years were associated with ADT administration. No differences in any endpoints were associated with ADT administration based on intermediate- vs. high-risk group or RT modality when analyzed separately. Patients with palpable disease plus Gleason ≥8 demonstrated improved clinical failure rates and a trend toward improved survival with ADT. Intermediate-risk patients treated with brachytherapy alone had improved biochemical control when ADT was given. Conclusion Benefits of ADT in the setting of dose-escalated RT remain poorly defined. This question must continue to be addressed in prospective study.

To assess the impact of PSA bounce (PB) on biochemical failure (BF) and clinical failure (CF) in brachytherapy patients treated with or without neoadjuvant androgen deprivation (AD).From 1987 to 2003, 691 patients with clinical stage T1-T3N0M0 prostate cancer were treated with external beam radiotherapy (EBRT) and high-dose-rate (HDR) brachytherapy boost (n=407), HDR brachytherapy alone (n=93), or permanent seed implant (n=191). Three hundred seventeen patients (46%) received neoadjuvant/adjuvant AD with RT. BF was scored using 3 definitions (ASTRO--3 rises, nadir+2 ng/ml, and threshold 3 ng/ml) based on current and absolute nadir (AN) methodologies. PB was defined as any increase in PSA followed by a decrease to the prior baseline or lower. The median followup was 4.0 years.Forty-six patients (7%) experienced CF at 5 years. PB ofor=0.1,or=1.0, andor=2.0 ng/ml at any time after RT occurred in 330 (48%), 60 (9%), and 22 patients (3%) respectively. The use of an AN definition reduced the likelihood of scoring PB as BF across all levels. The patients receiving AD experienced significantly longer bounce duration. Bounce1.0 ng/ml showed no association with CF. For bounceor=1.0 ng/ml, 10% demonstrated CF vs. 6% without bounce of this amplitude (p=0.27). Bouncesor=1.0 ng/ml were more likely to be scored as BFs for definitions based on current nadir (3 rises: 20% vs. 13%, nadir+2: 43% vs. 11%, 3 at/after nadir: 57% vs. 12%) than those based on AN (3 rises: 8% vs. 10%, nadir+2: 18% vs. 11%, 3 at/after nadir: 13% vs. 11%).Bouncesor=1.0 ng/ml are rare after brachytherapy with or without neoadjuvant AD, occurring in less than 10% of patients. Low PBs have little impact on BF, but as PB amplitude increases, the BF rate increases. BF definitions based on AN are less sensitive to PB after brachytherapy.

To review our institution's experience of treating patients with the MammoSite (Cytyc Corp., Marlborough, MA) breast brachytherapy catheter to deliver accelerated partial-breast irradiation (APBI), for determining short-term treatment efficacy, cosmesis, and toxicity.From January 2000 to April 2006, 80 patients treated with breast-conserving therapy (BCT) received adjuvant radiation using the MammoSite (34 Gy in 3.4-Gy fractions prescribed to 1.0 cm from the balloon surface). Twenty-three patients (29%) had Stage 0 breast cancer, 46 (57%) had Stage I breast cancer, and 11 (14%) had Stage II breast cancer. The median follow-up was 22.1 months.Two ipsilateral breast-tumor recurrences (IBTRs) (2.5%) developed for a 3-year actuarial rate of 2.9% (no regional failures were observed). On molecular-based clonality assay evaluation, both recurrences were clonally related. Younger age at diagnosis was the only variable associated with IBTR (continuous variable, p = 0.044; categorical variable [55 years vs./=55 years], p = 0.012). The percentages of patients with good/excellent cosmetic results at 12 and 36 months were 96.9% and 88.2%, respectively (p = NS). Patients with applicator-to-skin spacing7 mm and those who received adjuvant systemic chemotherapy exhibited lower rates of good/excellent cosmetic results, though the association was not statistically significant. The overall incidence of symptomatic seromas and any seromas was 10% and 45%, respectively. The overall incidence of fat necrosis and infections was 8.8% and 11.3%, respectively.Early-stage breast-cancer patients treated with adjuvant APBI using the MammoSite catheter exhibited a 3-year treatment efficacy, cosmesis, and toxicity similar to those observed with other forms of interstitial APBI at this length of follow-up.

e12054 Background: Most recurrences after breast conservative surgery (BCS) are around the index lesion. That’s the rational for APBI, which treats only this portion of the breast at the highest ri...

Prostate brachytherapy is an established treatment modality in early stage prostate cancer. We retrospectively reviewed our experience with low dose rate (LDR) and high dose rate (HDR) brachytherapy as a single treatment modality for early prostate cancer with emphasis on chronic toxicity.From June 1996 to August 2003, 253 patients with stage II prostate cancer, prostate specific antigen less than 12 and Gleason score less than 7 were treated with brachytherapy alone at our institution. A total of 92 patients underwent HDR brachytherapy with 192Ir, while 161 underwent LDR brachytherapy with 103Pd. HDR minimum prostate dose was 38 Gy, delivered in 4 fractions with a single implant during 36 hours. For HDR we used real-time dynamic 3-dimensional ultrasound base dosimetry. For 103Pd seed implants the dose was 120 Gy using selective peripheral weighted dose distribution. Treatment was given based on patient preference after pretreatment transrectal ultrasound. Toxicity was scored using the National Cancer Institute Common Toxicity Criteria 2.0. Median followup in all 253 cases was 2.9 years.In all patients the rate of 3-year urinary toxicity grade 2 or greater and grade 3 or greater was 26% and 6.9%, which was not significantly different between HDR and LDR (p = 0.3 and 0.4, respectively). However, grade 1 urogenital toxicity was lower for HDR (p = 0.002). The 3-year grade 2 rectal toxicity rate was 0.8% with no grade 3 or greater events, which was and similar in the HDR and LDR groups (1% and 0.6%, respectively). No cancer related deaths occurred and 4-year overall survival was 99% for HDR and 96.4% for LDR (p = 0.4). The 3-year American Society for Therapeutic Radiology and Oncology biochemical control rate was 90% for LDR and 93% for HDR. Cox multivariate analysis for grade 2 or greater urinary toxicity was significant for the use of 14 or greater needles (HR 6.1, p = 0.02) and hormonal therapy (HR 2.2, p = 0.02). In the absence of risk factors the 4-year grade 2 or greater urinary toxicity rate was 7% vs 65% if the 2 risk factors were present (p0.001). Impotence crude rates were 18.3% for HDR and 41.3% for LDR (p = 0.002).HDR and LDR chronic urinary toxicity grade 2 or greater rates were equivalent. However, grade 1 was lower for HDR. The impotence rate was decrease by half with HDR. Neoadjuvant hormonal therapy and 14 or greater needles were significantly associated with increased chronic urinary toxicity on multivariate analysis.

spacing of 1.0 cm and V-150%!30% (p 5 0.0001). Two patients healed after 6 months of conservative treatment. Surgery was required in six patients who developed fat necrosis. Conclusions: With median 72 month followup, Breast Conservation radiation therapy utilizing Interstitial Multi-Catheter HDR Implant has yielded local recurrence rates and cosmetic results which compare favorably to EBRT in selected patients. There was no difference in LR between patients with IDC and DCIS. Treatment with anthracycline based Chemotherapy, large (O200 cm) implant volumes, and V-150% O30%, appear to be relative contraindications to Interstitial HDR Implant. Finally, catheter spacing of 1 cm yielded optimal dosimetry and minimized complications. Compared to Mammosite technique, the Interstitial Multi-Catheter method offers greater flexibility of radiation delivery. Advantages include, no concern regarding surgical cavity shape irregularities, balloon conformality to surgical cavity, balloon rupture, balloon movement, air gaps, skin balloon proximity to skin, balloon shape distortion, and catheter movement within the balloon.

225 Background: Increasing age is a likely contributor to erectile dysfunction (ED) after radiotherapy for prostate cancer. A matched-pair (MP) analysis, with age as a criterion, was used to investigate ED after IMRT and HDR monotherapy for prostate cancer. Methods: 430 patients with low (63%) or intermediate risk (37%) prostate cancer with full or partial erectile function were treated between 4/00 and 9/10 with IMRT (n=215) or brachytherapy (n=215). Patients with follow up (FU) 10). BF was by modified Phoenix criteria (nadir+5 for 2y, nadir+2 after). Results: Median FU was 3.4y (range 1–7.1) for IMRT and 3.1y (range 1–10.9) for HDR. There was no difference in PSA (4.8 vs. 4.6, p=0.4), T stage (88% vs. 88% T1, p=1.0) and Gleason score (63% vs. 63% 6, p=1.0) between IMRT and HDR. Despite age matching, IMRT patients were older (median 65 vs. 62 y, p=0.05). Pre-treatment potency grade 0, 1, and 2 were found in 70%, 14% and 15% of IMRT and 69%, 20% and 11% of HDR patients. 5y OS, CSS, and BF were 100%, 100% and 2.4% for IMRT, and 99% (p=0.35), 100% (p=1.0), and 10.6% (p=0.001) for HDR. On subset analysis of pre-treatment grade 0 patients, univariate analysis showed HDR (p Conclusions: Both IMRT and HDR yield comparable low (25%) rates of 1+ ED for patients with no ED at baseline. Increasing age does not appear to significantly impact ED for both IMRT and HDR. [Table: see text]

rectum V50) were obtained corresponding to each image data set and the difference was recorded. Results: There were statistically significant differences in all DVH parameters between the 2 image data sets, with the exception of the V100. Excluding one patient in whom there was an 11% decrease in the V100 from 99.5 to 88.5 with and without stylets, the median decrease in prostate V100 was not significant. However, there was a 3.4% decrease for the V125 (p ! 0.001). For urethra V100, the difference was impressive with a mean of 6 and standard deviation (SD) of 12 between the 2 data sets (p ! 0.001). A similar large discrepancy was found for rectum V50 with a mean of 7 and SD of 11.9 (p! 0.001). Conclusions:Significant differenceswerenoted in terms ofDVHparameters between image data sets acquired with and without rigid stylets for the purpose of real-time intraoperative HDR planning for prostate BT. While the difference in terms of prostate coverage may not be clinically relevant, there were large variations in urethral and rectal dosimetry that may result in increased treatment-related toxicity. When using Flexiguide catheters for HDR prostate BT, we recommend performing the intraoperative planning based on an image set with the rigid stylets removed.

monotherapy patients, and 151.2Gy for the combination group. Our average urethral D30 was 129.5% for the monotherapy group, and 135.3% for the combination group. We have found a 1.8% incidence of urethral strictures, zero urethral ulcerations and zero incontinence. We have had 3.45% of patients that presented with urinary retention. Of these 2.4% presented within 1 month of the procedure. We had a further 0.88% of patients that developed urinary retention between 6 weeks and 3 months. Only 0.96% of patients required more than 2 weeks of intermittent selfcatheterisation. Further, we found that the average rectal V100 was 0,23cc in the monotherapy group. This group had 6.5% grade I and 0,8% grade II rectal complications. In the combination group the average rectal V100 was 0.19cc. This group had a 19.6% Grade I and 5.88% grade II rectal complications. These were all associated with the external beam radiotherapy. Zero grade III or IV complications have been noted in either group. We also found that erectile function was not significantly altered in previously potent patients. Although we cannot yet report conclusively on our control rates, our figures are currently showing a 3.2% failure rate. Conclusions: With a real-time feedback system and an accurate yet fast implant technique, we have achieved good quality implants consistently while ensuring that side-effects are kept to the minimum, especially when compared to published figures. These figures are still early and the high risk group needs to be removed from the greater cohort in order to assess the control rates within the various risk stratifications.

80 Background: To assess the prognostic value of percentage of positive biopsy cores (PPC) and perineural invasion (PNI) in predicting clinical outcome following radiotherapy (RT) for prostate cancer. Methods: One thousand and fifty-six patients with clinical stage T1-T3 N0 M0 prostate cancer, who had ≥ 4 biopsy cores sampled and complete biopsy core data available, were treated with either adaptive image-guided RT (median 75.6 Gy, n=387), low-dose EBRT (median 66.6 Gy, n=393), or EBRT and high-dose rate brachytherapy boost (n=276) at William Beaumont Hospital (1993-2004). Neoadjuvant and/or adjuvant androgen deprivation (AD) were given to 253 patients (24%). Multivariate cox regression analysis included PPC, gleason score, PSA, T stage, PNI, RT dose, androgen deprivation, and age. Biochemical failure (BF) was scored according to the Phoenix definition. Clinical failure (CF) was defined as any locoregional recurrence (LRR) or distant metastasis (DM). Median follow-up was 7.6 years. Results: Median cores sampled was 7, median PPC was 33%, and 18% had PNI. On univariate Cox regression, both PPC and PNI were predicators of biochemical failure and clinical failure (all P50% was associated with significantly higher DM (HR 4.01, 95% CI 1.86-8.61), and its independent predicative value remained significant whether AD was given or not (all P Conclusions: PPC is an independent and powerful predicator of DM for intermediate- and high-risk prostate cancer, regardless the use of AD. It should be considered for risk stratification and when designing for future trials testing adjuvant treatment after definitive RT for prostate cancer. No significant financial relationships to disclose.

71 Background: The purpose of this study was to compare clinical outcomes in a cohort of intermediate- and high-risk prostate cancer patients treated with either dose-escalated adaptive IGRT or pelvic external beam RT with high-dose rate brachytherapy boost (EBRT+HDR). Methods: 1,520 patients with clinical stage T1-T3 N0 M0 prostate cancer were treated with either CT-based offline adaptive IGRT (n=1,037) or EBRT+HDR, n=438) at William Beaumont Hospital. For IGRT, the CTV included the prostate and proximal seminal vesicles only. Median dose (minimum to cl-PTV) delivered via 3D conformal RT or intensity-modulated RT was 75.6 Gy (range: 73.8-79.2 Gy). For EBRT+HDR, the whole pelvis was treated to 46 Gy + 2 HDR implants with a median of 10.5 Gy (8.75-11.5 Gy) per implant. 208 patients from each group were matched based on criteria of pretreatment PSA ± 4 ng/mL, same Gleason score, T stage ± 2 sublevels, and use of neoadjuvant androgen deprivation therapy (ADT). Results: Mean follow-up was 5.1 years for IGRT vs 7.0 years for EBRT+HDR. Mean pretreatment PSA was 9 for both groups. Mean Gleason was 7 for both groups. EBRT+HDR patients were younger (67 vs 71 years, p Conclusions: In this matched-pair analysis of 416 patients, treatment of intermediate and high-risk prostate cancer with either offline adaptive IGRT or EBRT+HDR yielded excellent clinical outcomes without significant differences. The omission of pelvic radiotherapy in the IGRT patients did not appear to be associated with poorer clinical outcomes with modern high-dose RT. No significant financial relationships to disclose.

© 2014 American Brachytherapy Society. Purpose: To review and analyze the published data on high-dose-rate brachytherapy as monotherapy in the treatment of prostate cancer. Methods: A literature search and a systematic review of the high-dose-rate (HDR) brachytherapy (monotherapy) prostate literature were performed on PubMed using "high-dose-rate, brachytherapy, prostate, monotherapy" as search terms. More than 80 articles and abstracts published between 1990 and 2013 were identified. Data tables were generated and summary descriptions created. Commentary and opinion was formulated through discussion and consensus based on the critical review of the literature and the author's combined personal experience and knowledge. Results: Thirteen articles reported clinical outcome and toxicity with followup ranging from 1.5 to 8.0years. Results were available for all risk groups. A variety of dose and fractionation schedules were described. Prostate-specific antigen progression-free survival ranged from 79% to 100% and local control from 97% to 100%. The toxicity rates were low. Genitourinary toxicity, mainly frequency/urgency, was 0-16% (Grade 3). Gastrointestinal toxicity was 0-2% (Grade 3). Erectile function preservation was 67-89%. The radiobiological, clinical, and technical features of HDR brachytherapy were reviewed and discussed. Conclusions: Consistently high local tumor control and low complications rates are reported with HDR monotherapy. It provides reproducible high-quality dosimetry, it has an advantage from a radiobiology perspective, and it has a good radiation safety profile. HDR brachytherapy is a safe and effective local treatment modality for prostate cancer.

Aims and Background To report the technique of 3D-conformal radiation therapy (3D-CRT) currently used at our Institute for the treatment of prostate cancer with a curative intent. A critical review of the technical aspects of the technique is provided. Methods and Study Design Between December 1995 and October 2000, 334 patients with biopsy-proven adenocarcinoma of the prostate were treated with 3D-CRT. All patients were treated in a prone position with 15 MV X-ray beams and a 6-field technique for all but 20 patients, who were treated with a 3-field technique. Patients were simulated with the rectum and bladder empty. To ensure reproducible positioning, custom-made polyurethane foam or thermoplastic casts were produced for each patient. Subsequently, consecutive CT scan slices were obtained. The clinical target volume and critical organs (rectum and bladder) were identified on each CT slice. The beam's eye view technique was used to spatially display these structures, and the treatment portals were manually shaped based on the images obtained. The beam apertures were initially realized by conventional Cerrobend blocks (48 patients), which were replaced in October 1997 by a computer-driven multi-leaf collimator. The total target dose prescribed at the ICRU point is 76 Gy, delivered in 38 fractions and 54 days. The seminal vesicles are excluded at 70 Gy. Dose-volume histograms were obtained for all patients. If more than 30% of the bladder and/or more than 20% of the rectum receive >95% of the prescribed total dose, the treatment plan is judged as unsatisfactory and is adjusted. The dose-volume histogram can be improved by changing the beam's arrangement and/or weights or by introducing or modifying the wedge filters. Conclusions 3D-CRT in prostate cancer patients is a highly sophisticated and time-consuming method of dose delivery. Important technical issues remain to be clarified.