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Purpose To verify the dose sparing effect of hydrogel spacer (SpaceOAR™) on rectal dosimetry for prostate brachytherapy, and to determine whether prostate and rectal dosimetry was affected by the time gap between hydrogel spacer injection and brachytherapy dosimetry. Material and methods The 103Pd brachytherapy dosimetry of 174 consecutive intermediate- and high-risk patients injected with hydrogel was compared with a dosimetry of 174 contemporaneous patients without hydrogel injections. Of the SpaceOAR™ patients, 91 had hydrogel injected upon completion of brachytherapy implant, while the remaining 83 patients had hydrogel placed prior to external beam radiation therapy (EBRT), followed 2-10 weeks later by brachytherapy. Brachytherapy implants were either planned with the prostate undistorted by any hydrogel or planned with hydrogel in place. Dosimetry of the prostate and tissues at risk was determined from CT imaging on the day of brachytherapy implant. Results SpaceOAR™ significantly reduced mean and maximum rectal doses as well as rectal wall V50, but there was a statistically significant reduction of planning target volume (PTV) D90 to 121.1% of the prescribed dose in hydrogel patients compared to 123.3% in the non-hydrogel patients. Rectal dosimetry was similar between patients injected with hydrogel after brachytherapy and those with spacer injected prior to EBRT. However, patients who had hydrogel placed prior to EBRT had statistically significantly higher dosimetry indices of PTV and urethra relative to those with spacer placed at the completion of brachytherapy. Conclusions There was a significant rectal dose sparing in the cohort with hydrogel spacer compared to a reference group without spacer injection. The rectal dose sparing effect was similar in the sub-group of patients injected with hydrogel prior to EBRT and the sub-group injected with hydrogel at the conclusion of brachytherapy.

Purpose:To monitor the outcomes for intermediate-risk prostate cancer patients treated with biologically effective dose (BED) ≥ 200 Gy radiotherapy using low-dose-rate (LDR) brachytherapy., Material and methods:Between 2005 and 2016, a total of 397 patients with intermediate-risk prostate cancer were treated by LDR-based radiotherapy with a BED ≥ 200 Gy. Treatments consisted of LDR brachytherapy alone (177 cases) or LDR and external beam radiotherapy (EBRT) (220 cases). Short-term androgen deprivation therapy (ADT) was used in 186 patients (46.9%). The median follow-up period was 72 months (range 29-165 months). Dosimetric parameters and BED were studied in each case. The numbers of intermediate-risk features were: 163 patients with 1 intermediate-risk feature (41%), 169 patients with 2 intermediate-risk features (43%), and 65 patients with 3 intermediate-risk features (16%). A total of 145 cases were diagnosed as having primary Gleason pattern 4: Gleason score 4 + 3 (36.5%)., Results:Three patients developed biochemical failure, thus providing a 7-year actual biochemical failure-free survival (BFFS) rate of 99.1%. Biochemical failure was observed exclusively in cases with distant metastasis: two cases with lymph node metastasis and one case with bone metastasis, thus yielding a 7-year freedom from clinical failure (FFCF) rate of 99.1%. We observed eight deaths, but there was no death from prostate cancer, thus yielding a 7-year cause-specific survival (CSS) rate of 100%, and an overall survival (OS) rate of 98.4%., Conclusions:This study highlights excellent outcomes for intermediate-risk prostate cancer patients, including unfavorable intermediate-risk cases, treated with BED ≥ 200 Gy radiotherapy using LDR brachytherapy. LDR alone with a BED of 200 Gy may be an optimal treatment for both favorable and unfavorable intermediate-risk prostate cancer patients, although a longer follow-up is mandatory to confirm the present findings.

Purpose: To evaluate the feasibility and to report the early outcomes of focal treatment of prostate cancer using low- dose-rate brachytherapy (LDR-PB). Material and methods: Seventeen patients were screened with multi-parametric magnetic resonance imaging (mpMRI), 14 of whom proceeded to receive trans-perineal template mapping biopsy (TTMB). Focal LDR-PB was performed on five eligible patients using dual air kerma strength treatment plans based on planning target volumes derived from cancer locations and determined by TTMB. Patient follow-up includes prostate specific antigen (PSA) measurements, urinary and sexual function questionnaires, repeated imaging and TTMB at specific intervals post-treatment. Results: Feasibility of focal LDR-PB was shown and short-term outcomes are promising. While the detection rate of tumors, a majority of which were low grade GS 3 + 3, was found to be low on mpMRI (sensitivity of 37.5%), our results suggest the potential of mpMRI in detecting the presence of higher grade (GS ≥ 3 + 4), and bilateral disease indicating its usefulness as a screening tool for focal LDR-PB. Conclusions : Low-dose-rate brachytherapy is a favorable ablation option for focal treatment of prostate cancer, requiring minimal modification to the standard (whole gland) LDR-PB treatment, and appears to have a more favorable side effect profile. Further investigation, in the form of a larger study, is needed to assess the methods used and the long-term outcomes of focal LDR-PB.

Purpose Low-dose-rate (LDR) brachytherapy has been established as an effective and safe treatment option for men with low and intermediate risk prostate cancer. In this retrospective analysis, we sought to study the effect of body mass index (BMI) on post-implant dosimetric quality. Material and methods After institutional approval, records of patients with non-metastatic prostate cancer treated in Puerto Rico with LDR brachytherapy during 2008-2013 were reviewed. All patients were implanted with 125I seeds to a prescription dose of 145 Gy. Computed tomography (CT) based dosimetry was performed 1 month after implant. Patients with at least 1 year of prostate-specific antigen (PSA) follow-up were included. Factors predictive of adequate D90 coverage (≥ 140 Gy) were compared via the Pearson χ2 or Wilcoxon rank-sum test as appropriate. Results One-hundred and four patients were included in this study, with 53 (51%) patients having a D90 ≥ 140 Gy. The only factor associated with a dosimetric coverage detriment (D90 < 140 Gy) was BMI ≥ 25 kg/m2 (p = 0.03). Prostate volume (p = 0.26), initial PSA (p = 0.236), age (p = 0.49), hormone use (p = 0.93), percent of cores positive (p = 0.95), risk group (p = 0.24), tumor stage (p = 0.66), and Gleason score (p = 0.61) did not predict D90. Conclusions In this study we show that BMI is a significant pre-implant predictor of D90 (< 140 Gy vs. ≥ 140 Gy). Although other studies have reported that prostate volume also affects D90, our study did not find this correlation to be statistically significant, likely because all of our patients had a prostate volume < 50 cc. Our study suggests that in patients with higher BMI values, more rigorous peri-implant dosimetric parameters may need to be applied in order to achieve a target D90 > 140 Gy.

PURPOSE: To analyze the seed loss and displacement and their dosimetric impact in prostate low-dose-rate (LDR) brachytherapy while utilizing the combination of loose and stranded seeds. MATERIAL AND METHODS: Two hundred and seventeen prostate cancer patients have been treated with LDR brachytherapy. Loose seeds were implanted in the prostate center and stranded seeds in the periphery of the gland. Patients were imaged with transrectal ultrasound before implant and with computerized tomography/magnetic resonance imaging (CT/MR) one month after implant. The seed loss and displacement had been analyzed. Their impact on prostate dosimetry had been examined. The seed distribution beyond the prostate inferior boundary had been studied. RESULTS: The mean number of seeds per patient that were lost to lung, pelvis/abdomen, urine, or unknown destinations was 0.21, 0.13, 0.03, and 0.29, respectively. Overall, 40.1% of patients had seed loss. Seed migration to lung and pelvis/abdomen occurred in 15.5% and 10.5% of the patients, respectively. Documented seed loss to urine was found in 3% of the patients while 20% of patients had seed loss to unknown destinations. Prostate length difference between pre-plan and post-implant images was within 6 mm in more than 98% of cases. The difference in number of seeds inferior to prostate between pre-plan and post-implant dosimetry was within 7 seeds for 93% of patients. At time of implant, 98% of seeds, inferior to prostate, were within 5 mm and 100% within 15 mm, and in one month post-implant 83% within 9 mm and 96.3% within 15 mm. Prostate post-implant V100, D90, and rectal wall RV100 for patients without seed loss were 94.6%, 113.9%, and 0.98 cm(3), respectively, as compared to 95.0%, 114.8%, and 0.95 cm(3) for the group with seed loss. CONCLUSIONS: Seed loss and displacement have been observed to be frequent. No correlation between seed loss and displacement and post-plan dosimetry has been reported.

Purpose: To investigate the dosimetric difference due to the different point A definitions in cervical cancer lowdose-rate (LDR) intracavitary brachytherapy. Material and methods: Twenty CT-based LDR brachytherapy plans of 11 cervical patients were retrospectively reviewed. Two plans with point As following the modified Manchester system which defines point A being 2 cm superior to the cervical os along the tandem and 2 cm lateral (A os ), and the American Brachytherapy Society (ABS) guideline definition in which the point A is 2 cm superior to the vaginal fornices instead of os (A ovoid ) were generated. Using the same source strength, two plans prescribed the same dose to A os and A ovoid . Dosimetric differences between plans including point A dose rate, treatment volume encompassed by the prescription isodose line (TV), and dose rate of 2 cc of the rectum and bladder to the prescription dose were measured. Results: On average A ovoid was 8.9 mm superior to A os along the tandem direction with a standard deviation of 5.4 mm. With the same source strength and arrangement, A os dose rate was 19% higher than A ovoid dose rate. The average TV(A ovoid ) was 118.0 cc, which was 30% more than the average TV(A os ) of 93.0 cc. D 2cc /D(A prescribe ) increased from 51% to 60% for rectum, and increased from 89% and 106% for bladder, if the prescription point changed from A os to A ovoid . Conclusions: Different point A definitions lead to significant dose differences. Careful consideration should be given when changing practice from one point A definition to another, to ensure dosimetric and clinical equivalency from the previous clinical experiences. J Contemp Brachytherapy 2013; 5, 4: 222–226 DOI: 10.5114/jcb.2013.38836

Purpose: Post-implant dosimetry following prostate seed implantation (PSI) occasionally reveals suboptimal dosi- metric coverage of the gland. Published reports of re-implantation techniques have focused on earlier-generation tech- niques, including preplanned approaches and stranded seeds. The purpose of this case report is to describe a customizable approach to perform corrective re-implantation using loose seeds and intraoperative planning technique. Material and methods: This case report describes a 63-year-old male with favorable risk prostate adenocarcinoma receiving PSI. Thirty day post-implant dosimetric evaluation revealed suboptimal coverage of the base of the gland. Us- ing guidance from post-implant CT-images and real-time planning, the patient received a corrective re-implantation with intraoperative planning. Results: Post-implant dosimetry after re-implantation procedure with intraoperative planning yielded improved tar- get volume coverage that achieved standard dosimetric criteria. Conclusions: Re-implantation as a salvage treatment technique after sub-optimal PSI is a valid treatment option per- formed with intraoperative real-time planning. J Contemp Brachyther 2012; 4, 3: 176-181 DOI: 10.5114/jcb.2012.30684

Purpose: Adjuvant high-dose-rate brachytherapy (HDRBT) offers advantages over low dose rate brachytherapy (LDRBT), although there are little data on local tumor control and treatment related toxicity. We report outcome in patients with primary, recurrent, and metastatic extremity and superficial trunk soft tissue sarcoma. Material and methods: Eleven patients (12 sites) with intermediate or high grade sarcoma were treated with adju vant HDRBT following surgical resection. Patients were treated at 3.4 Gy fractions delivered twice daily to a total dose of 34 Gy (1 patient received 9 fractions). Results: With median follow-up of 20.8 months, 1 patient developed a local recurrence. 2-year local control and overall survival are 89% and 71%, respectively. Wound complications occurred in 3 sites. Two of the wound complica tions developed in the area of previous external beam radiotherapy (EBRT). Conclusion: Surgical resection followed by HDRBT is associated with excellent early local tumor control and accept able wound complication. J Contemp Brachyther 2011; 3, 1: 3-10 DOI: 10.5114/jcb.2011.21036

Purpose: In order to know the effect of variation in position of applicators to the dose received by the tumor volume, critical organs such as rectum and bladder and the correlation of variation on the clinical outcome. Material and methods: 36 patients with histologically proven cervical cancer, undergoing intracavitary brachythe rapy (ICBT) from October 2005 to December 2006 were the subjects of the study. Two pairs of orthogonal X-ray films were taken: one prior to loading of sources and the other after removal of sources. These patients were followed up as per the RTOG criteria. Results: The median duration of insertion was 25 hours with a median follow up period of 6.7 months. The translational variation of the applicator position for all patients was 3 mm and 1 mm (2 SD), respectively, in the patient’s lateral and antero-posterior direction. The rotational variation was 3 and 4 degrees (2 SD) in the patient’s transverse and sagittal planes. Detailed analysis of source movement showed following changes in median dose: point A: 14%, point B: 2%, point P: 1%, Rectum 1: 3.5%, Rectum 2: 4% and Bladder: 9.1%. The incidence of rectal toxicity was 6/36 (16.7%) and that of bladder was 1/36 (2.8%). When the variables were grouped to evaluate the relationship, our study showed statistically significant relationship between: R2 and rectal toxicity (p value: 0.002), point A and rectal toxicity (Pearson: 0.792), lateral displacement/anteroposterior displacement and rectal toxicity (p value: 0.012/0.003), beta angle and R2 (p value: 0.002). Conclusions: The geometric relationships between the ICBT applicators and the critical structures vary during the course of low dose rate brachytherapy. Source movement does result in significant dose alterations in terms of increased rate of complications, but its impact on cure rates needs to be studied in the future. J Contemp Brachyther 2010; 2, 3: 93-97 DOI: 10.5114/jcb.2010.16919