Faculty Bibliography

PURPOSE:Prostate low-dose-rate (LDR) brachytherapy involves implantation of radioactive seeds permanently into the prostate gland. During receptive anal intercourse, the penis of the partner may come in close proximity to the implanted prostate gland. We estimate the potential intrarectal dose rates and suggest guidance on radiation precautions. METHODS AND MATERIALS:One hundred two patients were included in the study. After implantation, with patients under anesthesia in the dorsal lithotomy position, a new set of ultrasound (US) images and a CT scan were obtained. The images were fused, radioactive seeds and US probe locations were determined on the CT, and prostate, bladder, and rectal contours were drawn on the US. Dose rates (cGy/h) were calculated for the portion of the US probe spanning the prostate for several dose-volume histogram parameters. RESULTS:Twenty patients were treated with (125)I and 82 patients with (103)Pd. Average dose rates at Day 0 to the portion of the US probe spanning the prostate were 2.1 ± 1.3 cGy/h and 2.5 ± 0.8 cGy/h for patients treated with (125)I and (103)Pd, respectively. After 60 days, average calculated probe dose drops to 1.0 ± 0.6 cGy/h and 0.2 ± 0.1 cGy/h for (125)I and (103)Pd, respectively. CONCLUSIONS:During the immediate weeks after prostate seed implant, the estimated intrarectal dose rates are higher in (103)Pd compared to (125)I. As (103)Pd decays faster than (125)I, 2 months after the implant, radiation exposure from (103)Pd becomes lower than (125)I. Receptive anal intercourse time should be kept as low as possible during 2 and 6 months after low-dose-rate brachytherapy of the prostate with (103)Pd and (125)I, respectively.

PURPOSE:Value, defined as outcomes over costs, has been proposed as a measure to evaluate prostate cancer (PCa) treatments. We analyzed standardized outcomes and time-driven activity-based costing (TDABC) for prostate brachytherapy (PBT) to define a value framework. METHODS AND MATERIALS:Patients with low-risk PCa treated with low-dose-rate PBT between 1998 and 2009 were included. Outcomes were recorded according to the International Consortium for Health Outcomes Measurement standard set, which includes acute toxicity, patient-reported outcomes, and recurrence and survival outcomes. Patient-level costs to 1 year after PBT were collected using TDABC. Process mapping and radar chart analyses were conducted to visualize this value framework. RESULTS:A total of 238 men were eligible for analysis. Median age was 64 (range, 46-81). Median followup was 5 years (0.5-12.1). There were no acute Grade 3-5 complications. Expanded Prostate Cancer Index Composite 50 scores were favorable, with no clinically significant changes from baseline to last followup at 48 months for urinary incontinence/bother, bowel bother, sexual function, and vitality. Ten-year outcomes were favorable, including biochemical failure-free survival of 84.1%, metastasis-free survival 99.6%, PCa-specific survival 100%, and overall survival 88.6%. TDABC analysis demonstrated low resource utilization for PBT, with 41% and 10% of costs occurring in the operating room and with the MRI scan, respectively. The radar chart allowed direct visualization of outcomes and costs. CONCLUSIONS:We successfully created a visual framework to define the value of PBT using the International Consortium for Health Outcomes Measurement standard set and TDABC costs. PBT is associated with excellent outcomes and low costs. Widespread adoption of this methodology will enable value comparisons across providers, institutions, and treatment modalities.

PURPOSE/OBJECTIVE:We provide a comprehensive analysis of anatomical patterns of recurrence following external beam radiotherapy in patients with localized prostate cancer. MATERIALS AND METHODS/METHODS:This retrospective analysis included 2,694 patients with localized prostate cancer who received definitive, dose escalated external beam radiotherapy from 1991 to 2008. First recurrence sites were defined as initial sites of clinically detected recurrence and any subsequent clinically detected recurrence within 3 months. Anatomical recurrence patterns were classified as local (prostate/seminal vesicles only), lymphotropic (lymph nodes only) and osteotropic (bones only) in patients with disease confined only to these respective sites for at least 2 years from the initial clinically detected recurrence. RESULTS:Prostate was the most common first recurrence site in the low, intermediate and high risk groups with an 8-year cumulative incidence of 3.5%, 9.8% and 14.6%, respectively. The 8-year risk of isolated pelvic lymph node relapse as the first recurrence site was 0%, 1.0% and 3.3%, respectively. In the 474 patients with clinically detected recurrence the most common first recurrence site was local in 55.3%, bone in 33.5%, pelvic lymph nodes in 21.3% and abdominal lymph nodes in 9.1%. Patients showed unique relapse distributions, including a pattern that was local in 41.6%, lymphotropic in 9.7%, osteotropic in 20.3% and multiorgan/visceral in 28.5%. Anatomical recurrence pattern was the strongest predictor of prostate cancer specific mortality on multivariate analysis of patients with clinically detected recurrence. CONCLUSIONS:The most common first recurrence site after dose escalated external beam radiotherapy for prostate cancer is in the prostate and seminal vesicles in all risk groups. In contrast, patients treated without elective pelvic lymph node irradiation are at relatively low risk for isolated pelvic lymph node relapse. Recurrence patterns revealed a tropism for specific anatomical distributions with divergent prognoses, suggesting underlying biological differences among tumors.

OBJECTIVE:To evaluate whether a history of smoking or smoking during therapy after external beam radiotherapy (EBRT) for clinically localised prostate cancer is associated with increased treatment-related toxicity or disease progression. PATIENTS AND METHODS/METHODS:Of 2358 patients receiving EBRT for prostate cancer between 1988 and 2005, 2156 had chart-recorded smoking histories. Patients were classified as 'never smokers', 'current smokers', 'former smokers', and 'current smoking unknown'. Variables considered included quantity of tobacco use in pack-years, duration of smoking, and, for former smokers, how long before initiation of RT the patient quit smoking, when available. The median EBRT dose was 8100 Gy and the median follow-up was 95 months. Toxicity was graded according to the National Cancer Institute's Common Terminology Criteria for Adverse Events. RESULTS:Current smoking significantly increased the risks of both prostate-specific antigen relapse [hazard ratio (HR) 1.4, P = 0.02] and distant metastases (HR 2.37, P < 0.001), as well as prostate cancer-specific death (HR 2.25, P < 0.001). Multivariate analysis showed that smoking was also associated with increased risk of EBRT-related genitourinary toxicities (current smoker, HR 1.8, P = 0.02; former smoker, HR 1.45, P = 0.01). Smoking did not increase gastrointestinal toxicity. CONCLUSIONS:Current smokers with prostate cancer are at increased risk of biochemical recurrence, distant metastasis, and prostate cancer-related mortality after definitive RT to the prostate. Current and former smokers, regardless of duration and quantity of exposure, are at an increased risk of long-term genitourinary toxicity after EBRT. Oncologists should encourage patients to participate in smoking-cessation programmes before therapy to potentially lower their risk of relapsing disease and post-treatment toxicities.