Thinner 20G needles are being used in place of 18G needles for implantation of 125I prostate brachytherapy seeds at the British Columbia Cancer Agency (BCCA). The purpose of this study is to review differences in toxicity and dosimetry among patients treated with 20G and 18G strands. Thinner needles are hypothesized to cause less implantation trauma, and therefore fewer associated genito-urinary (GU) and gastro-intestinal (GI) side effects. This is a retrospective analysis of patients treated with prostate brachytherapy with Oncura Inc. 20G ThinSeed™ (9011) and 18G OncoSeed™ (6711) strands. All patients were treated by 3 experienced radiation oncologists. Equal number of consecutive patients treated with ThinSeed™ (9011) and OncoSeed™ (6711) (treated just prior to switching) were selected. Patient-administered international prostate symptom scores (IPSS), sexual health inventory for men scores (SHIM) were collected at baseline, 6 weeks, and 6 months post-implantation. Acute toxicity was also graded by physicians according to the Radiation Therapy Oncology Group (RTOG) scale for GU and GI toxicity. Brachytherapy dosimetry was calculated on post-implantation day 0- CT scan, and compared between treatment groups. Three hundred thirty-six patients treated between 2008 and 2012 were included in this analysis, 50% (168) were treated with ThinSeed™ (9011) and 50% with OncoSeed™ (6711). Six-week followup data was available for 215 patients, and 6-month followup for 166. Post-implant dosimetry and baseline characteristics were available for all 336. There was no difference in baseline IPSS and SHIM score between the two groups. At 6-weeks and 6-months post implant no statistically significant difference between groups was found with respect to IPSS, SHIM, catheterization rate, or acute GU RTOG toxicity. There was a significant difference in acute GI RTOG favoring the OncoSeed™ (6711). At 6 weeks ThinSeed™ (9011) patients had 32.4% Gr 1 and 8.8% Gr 2 toxicity, while OncoSeed™ (6711), only 3.8% had gr. 1 and 3.8% gr. 2 toxicity (p<0.0001 with Wilcoxon rank sum test). At 6-month followup, GI RTOG again approached significance with 27.1% (19/70) ThinSeed™ (9011) patients experiencing grade 1 or higher toxicity and 16.7% (16/96) OncoSeed™ (6711) patients experiencing grade 1 or higher toxicity (p=0.078). Kaplan-Meier analysis of time to IPSS resolution to pre-implant levels for the two groups did not differ (p=0.47 log-rank test). On post implant dosimetry, ThinSeed™ (9011) patients had higher mean prostate V100 (95% vs 92%, p<.001) and mean prostate D90 (113Gy vs 107Gy, p<.001). Mean rectal V100 was also higher in the ThinSeed™ (9011) patients (0.4cc vs. 0.3cc p= 0.004). There was no statistically significant difference with respect to urethral dosimetry. Mean prostate volume post implant was smaller among patients treated with ThinSeed™ (9011) (44cc vs 49cc, p<.001). This retrospective analysis of patients treated with ThinSeed™ (9011) and OncoSeed™ (6711) did not support the hypothesis that thinner needles reduce toxicity. Urinary and sexual symptoms were equivalent between the treatment groups, while rectal dose and toxicity was higher among those treated with the ThinSeed™ (9011). It is possible that thinner needles reduce trauma and edema in implanted tissue, as supported by the observed smaller post-implant mean prostate volumes of our thin strand patients. Reduced edema, however, may cause closer proximity of implanted sources to the rectum, and subsequently increase rectal dose and GI toxicity.

PURPOSE: To describe in detail British Columbia (BC) Cancer Agency (BCCA) Provincial Prostate Brachytherapy (PB) Quality Assurance (QA) Program.METHODS AND MATERIALS: The BCCA PB Program was established in 1997. It operates as one system, unified and supported by electronic and information systems, making it a single PB treatment provider for province of BC and Yukon. To date, >4000 patients have received PB (450 implants in 2011), making it the largest program in Canada. The Program maintains a large provincial prospective electronic database with records on all patients, including disease characteristics, risk stratification, pathology, preplan and postimplant dosimetric data, follow-up of prostate-specific antigen, and toxicity outcomes.RESULTS: QA was an integral part of the program since its inception. A formal QA Program was established in 2002, with key components that include: unified eligibility criteria and planning system, comprehensive database, physics and oncologist training and mentorship programs, peer review process, individual performance outcomes and feedback process, structured continuing education and routine assessment of the program's dosimetry, toxicity and prostate-specific antigen outcomes, administration and program leadership that promotes a strong culture of patient safety. The emphasis on creating a robust, broad-based network of skilled providers has been achieved by the program's requirements for training, education, and the QA process.CONCLUSIONS: The formal QA process is considered a key factor for the success of cancer control outcomes achieved at BCCA. Although this QA model may not be wholly transferable to all PB programs, some of its key components may be applicable to other programs to ensure quality in PB and patient safety. Crown Copyright (C) 2013 Published by Elsevier Inc. on behalf of American Brachytherapy Society. All rights reserved.

OBJECTIVE: To describe the acute and late rectal toxicity in 1006 prostate brachytherapy patients implanted 1998-2003. To determine whether rectal dose-volume histogram as well as patient and treatment factors were associated with rectal toxicity.METHODS AND MATERIALS: Median followup was 60.7 months. Rectal dosimetry was calculated as dose-volume histogram of the rectum using Day 28 CT-based dosimetry and expressed as volume of the rectum in cc receiving 50%, 100%, and 150% of the prescription dose (VR50cc, VR100cc, and VR150cc, respectively). Univariate and multivariate analyses were performed to examine the influence of patient, implant, dosimetry, and learning curve factors on the development of acute and late toxicities using a modified Radiation Therapy Oncology Group (RTOG) scale. Acute toxicity was analyzed using logistic regression and late toxicity using Cox proportional hazards regression. Analysis of variance was used to examine the association between rectal toxicity and rectal dose.RESULTS: Rectal dosimetry in 93.5% and rectal toxicity in 96.2% have been recorded. Median VR100 = 1.05 cc. Late RTOG Grades 0, 1, 2, 3, and 4 were recorded in 68%, 23%, 7.3%, 0.9%, and 0.2% patients, respectively. On multivariate analysis, acute RTOG >= 2 rectal toxicity was associated with urinary retention (p = 0.036) and learning curve (p = 0.015); late RTOG >= 2 was associated with the presence of acute toxicity (p = 0.0074), higher VR100 (p = 0.030) and learning curve (p = 0.027).CONCLUSIONS: Late rectal RTOG >= 2 rectal toxicity in this cohort was 8%. Increased VR100, presence of acute rectal toxicity, and learning curve were associated with higher rate of late RTOG >= 2 toxicity. Severe late rectal toxicity after prostate brachytherapy was rare. Crown Copyright (C) 2012 Published by Elsevier Inc. on behalf of American Brachytherapy Society. All rights reserved.

Purpose: To describe system of novel quality assurance implemented after ABS 2010 in a large multicenter Provincial British Columbia Cancer Agency (BCCA) Prostate Brachytherapy Program with 14 practicing oncologist in 4 regional cancer centers. Materials and Methods: Prostate Brachytherapy is available in 4 regional cancer centers in the province of BC, servicing 5 million people in British Columbia and the Yukon, Canada. The program is administered under the Provincial Prostate Brachytherapy Program umbrella, which provides guidelines for uniform eligibility criteria, planning, and delivery of pre- planned 125 I LDR monotherapy. Since July 1998, over 3000 patients have been implanted and entered into a large prospective database containing baseline clinical and dosimetric data, followup prostate-specific antigen (PSA), and testosterone levels. Toxicity data are collected from all patients who had attended one of four BCCA regional cancer centers. The program maintains Quality Assurance (QA) procedures that include: bi annual QA meetings, educational sessions, audits of dosimetrically suboptimal implants, practice audits, education and mentorship of new brachyterapists in the program. Recently, a questionnaire was sent to all practicing oncologists with specific questions regarding expanding the QA reporting to include anonymous individual, dosimetric, toxicity and PSA outcomes to be available on-line, real-time for each brachytherapist by year, and for the program as a whole. Results: All 14 oncologists completed the survey. The average minimal and optimal number of implants needed to maintain clinical competence per year was felt to be 20 and 30, respectively. All but one individual expressed a strong interest to have individual QA outcomes (dosimetry, toxicity and PSA outcomes) readily available anonymously and with pass word protection. The information provided would include dosimetry (prostate V100, D90, rectum VR100, urethra UD50% US/ CT volume ratio) toxicity; (% normalization of IPSS at 12 mo, urinary RTOG 2 and 3 toxicity, AUR rate (acute urinary obstruction), rectal RTOG 2 and 3 toxicity), and PSA failure rates for patients with > 4 years followup. The existing database has been modified to provide oncologists with anonymous on-line, individual feedback that includes individual data and overall program data with minimum and maximum parameters. All 14 oncologists also supported random implant audits. Random examples of individual and collective data will be presented at the meeting. Six month followup questionnaire will be administered to assess effectiveness of this novel QA process. Conclusions: Quality assurance is most meaningful if each individual is aware of his/her own patients' results. This information would help to complete the feedback loop and facilitate improvement in quality, perhaps shortening the learning curve for individual oncologists and the program as a whole.

Purpose: To describe the acute and late rectal toxicity in 1006 uniformly treated prostate brachytherapy patients and determine whether rectal DVH, patient or treatment factors are associated with rectal toxicity. Materials and Methods: 1006 consecutive patients implanted between August 1989 and October 2003 (median followup: 60 mo, range: 11-124 mo) were included. Rectal dosimetry was calculated as rectal DVH using 30 day post implant CT. Logistic regression model examined the significance of patient, implant and dosimetry factors (prostate V100, V150 and D90 and rectal VR150, VR100 and VR50 (volume of the rectum receiving 150%, 100% and 50% of the prescribed dose in cc) on development of acute rectal toxicity (<6 months), subacute (6 months) and late (>12 months after the implant) using modified RTOG scale. Results: Acute, subacute and late grade 1 rectal toxicity developed in 19%, 12% and 23% and grade 2 in 6%, 3% and 7.4%,respectively, late grade 3 toxicity in 1% and late grade 4 in 0.2% of patients. Factors associated with acute ≥ grade 2 toxicity were need for any or prolonged catheterization (p = 0.02 and 0.03, respectively). Factors associated with late ≥ grade 2 toxicity were no hormone therapy (p = 0.03, HR = 0.61) and presence of acute toxicity (p < 0.0001 with acute grade 1 toxicity, HR = 2.77, with acute grade 2 toxicity, HR = 4). Dosimetry factors associate with late grade ≥ 1 toxicity were: prostate V150 (p = 0.04, HR=1.01), rectal VR150 (p = 0.01, HR = 1.3), VR100 (p = 0.0007, HR = 1.1), VR 50 (p = 0.003, HR = 1.05). Late grade ≥ 2 toxicity was associated with VR 150 (p = 0.07, HR = 1.4), VR 100 (p = 0.02 HR = 1.2). Multivariate analysis will be presented at the meeting. Conclusions: Late rectal ≥2 toxicity in this cohort is 8%. Catheterization is associated with higher rate of any acute rectal toxicity. Higher rectal dose and acute rectal toxicity are associated with late ≥2 rectal toxicity. Severe late rectal toxicity after prostate brachytherapy is very rare.

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 (5) 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 125, 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 I-125 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. (C) 2009 Elsevier Inc.