Faculty Bibliography

PURPOSE/OBJECTIVE(S): Historically, caution has been warranted when irradiating large target volumes particularly those in close proximity to organs at risk. Prior literature has demonstrated an increased incidence of GI and GU toxicity when men with large prostates were treated with conventionally fractionated radiation therapy. However, there is very limited data regarding the clinical outcomes when SBRT is used as a definitive treatment modality. We explore the long term oncologic, toxicity, and patient reported outcomes of men treated with definitive SBRT with ultra-large prostate glands (>= 100 cc.) MATERIALS/METHODS: From 2006 to 2020, a total of 3,393 patients with low and intermediate risk prostate cancer were treated with definitive robotic-SBRT. We performed a retrospective review to identify all patients in this cohort with pre-treatment prostate volumes >= 100 cc. Prostate volume was measured at the time of treatment regardless of ADT incorporation. All patients were treated to a total dose of 35-36.25 Gy in 5 fractions. All patients had a minimum of 2 years follow-up and were given pre- and post-treatment EPIC questionnaires at defined intervals. Biochemical control was assessed using the Phoenix definition. Late toxicity was defined using CTCAE version 5.0 and was characterized as occurring >= 6 months post treatment.
RESULT(S): A total of 67 patients were identified with >= 100 cc prostate glands. Of these, 18 patients received ADT prior to treatment. Overall, the median prostate volume was 139.37 cc (range 100.1 - 227 cc). The D'Amico risk classification was low (n=19) and intermediate (n=48). The median age was 70 years (range 54 - 87 years) and the median pretreatment PSA was 8.7 ng/ml. The mean pre-treatment EPIC bowel and urinary scores were 87.8 and 79.7, respectively. One-month following SBRT, mean EPIC bowel and urinary scores worsened to 83.6 and 76.5, respectively. Three months following SBRT, mean epic bowel and urinary scores continued to decline to 83.2 and 77.1, respectively. However, bowel and bladder symptomatology improved by 1 year to 86.16 and 77.19, and by 2 years improved above baseline to 90.00 and 85.78, respectively. There were no high grade (3+) GI toxicities observed, though one grade 3 urinary retention was identified. Excellent oncologic outcomes were observed with a 5-year median PSA nadir of 0.6 ng/mL and a biochemical relapse free survival (bRFS) of 100% at 5 years.
CONCLUSION(S): SBRT has been demonstrated to be oncologically effective with minimal toxicity, and has become a more ubiquitous radiation option in men with localized prostate cancer. Although there is a historical reticence for treatment of men with large glands, we report excellent clinical outcomes. Five-year bRFS was 100% and grade 3+ urinary toxicity was 2%. Although EPIC scores transiently dropped at 1 and 3 months following SBRT, resolution was seen by 1 year following treatment. The use of SBRT for the treatment of localized prostate cancer in men with ultra-large prostate gland is feasible with minimal toxicity.
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PURPOSE/OBJECTIVE(S): Stereotactic Body Radiation Therapy (SBRT) is a standard therapeutic option for men with prostate adenocarcinoma. The median age of prostate cancer in the US is 66 but patients as young as 35 have been reported. Many younger patients will have surgery rather than SBRT for localized prostate cancer but some will be treated with SBRT. There is a paucity of data on the outcomes of this younger subset. This study reports outcomes on patients younger than 50 treated with SBRT at a single institution and compares outcomes to older patients. MATERIALS/METHODS: Between April 2006 and December 2020, 3626 patients with prostate cancer were treated with inhomogeneous-dosed SBRT using a robotic linear accelerator and followed at an academic institution. 3173 (87.51%) of patients were treated with a median dose of 3500cGY (3500-3625) delivered over 5 consecutive fractions prescribed to the 83-85% isodose line, and the remaining 453 (12.49%) other patients receiving a median dose of 4500cGY (4500-5400) to the pelvis in conventional fractionation followed by a 3 fraction SBRT boost of 2100 cGY (1950-2100) over 3 consecutive fractions. Androgen deprivation Therapy (ADT) was prescribed in 865 (23.86%) of these cases. The mean age was 67.3 years old. 47 patients were younger than 50 years old (mean age 46.6). 3,579 patients were 50 or older. Patients were divided into prognostic D'Amico risk groups with 44.68%, 48.94%, 6.38% of patients falling in the low, intermediate, and high-risk stratifications in the younger cohort and 24.76%, 56.83%, 18.41% in the older cohort respectively. Pretreatment PSA was 1.72 - 43.2 (median: 5.4) in the younger group and 0.3 - 661 (median: 6.5) in the older group. In the younger group, Gleason scores were 6 in 48.94%, 7 in 46.81%, and 8-10 in 4.25%. 44 younger patients were treated with SBRT alone. 3 patients also received supplemental external beam radiation (median dose 4500cGY) and 5 patients (10.6%) received Androgen Deprivation Therapy (ADT) as part of their treatment regimen. In the older group, Gleason scores were 6 in 30.57%, 7 in 54.06%, and 8-10 in 15.37%. 3129 were treated with SBRT alone. 450 patients also received supplemental external beam radiation (median dose 4500cGY) and 860 patients (24.03%) received Androgen Deprivation Therapy (ADT) as part of their treatment regimen.
RESULT(S): At 64.8 months (range 7 months - 177 months) the 5-year biochemical relapse free survival was 98% in younger patients compared to 99% in older patients using the Phoenix definition of biochemical failure. The 5-year median post treatment PSA was 0.15 in the younger patients and 0.20 in the older patients. There were no significant differences in biochemical relapse free survival between the groups.
CONCLUSION(S): This represents the largest series evaluating outcomes in very young patients treated with definitive SBRT for prostate cancer. With 5-year follow up, SBRT is an effective treatment for this younger subset of patients. Continued follow up will be required to see if these results remain durable.
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BACKGROUND:Historically, IBD has been thought to increase the underlying risk of radiation related toxicity in the treatment of prostate cancer. In the modern era, contemporary radiation planning and delivery may mitigate radiation-related toxicity in this theoretically high-risk cohort. This is the first manuscript to report clinical outcomes for men diagnosed with prostate cancer and underlying IBD curatively treated with stereotactic body radiation therapy (SBRT). METHODS:A large institutional database of patients (n = 4245) treated with SBRT for adenocarcinoma of the prostate was interrogated to identify patients who were diagnosed with underlying IBD prior to treatment. All patients were treated with SBRT over five treatment fractions using a robotic radiosurgical platform and fiducial tracking. Baseline IBD characteristics including IBD subtype, pre-SBRT IBD medications, and EPIC bowel questionnaires were reviewed for the IBD cohort. Acute and late toxicity was evaluated using the CTCAE version 5.0. RESULTS:A total of 31 patients were identified who had underlying IBD prior to SBRT for the curative treatment of prostate cancer. The majority (n = 18) were diagnosed with ulcerative colitis and were being treated with local steroid suppositories for IBD. No biochemical relapses were observed in the IBD cohort with early follow up. High-grade acute and late toxicities were rare (n = 1, grade 3 proctitis) with a median time to any GI toxicity of 22 months. Hemorrhoidal flare was the most common low-grade toxicity observed (n = 3). CONCLUSION/CONCLUSIONS:To date, this is one of the largest groups of patients with IBD treated safely and effectively with radiation for prostate cancer and the only review of patients treated with SBRT. Caution is warranted when delivering therapeutic radiation to patients with IBD, however modern radiation techniques appear to have mitigated the risk of GI side effects.

Background and Purpose: Fiducial marker placement is required in patients undergoing robotic-based Stereotactic Body Radiotherapy (SBRT) or image-guided radiation therapy (IGRT) for prostate cancer. Many patients take antiplatelet or anticoagulant medication due to other medical comorbidities. They are often required to temporarily discontinue these medications prior to invasive medical procedures as they are prone to bleed. Some patients are unable to discontinue therapy due to an elevated risk of thromboembolic events. The purpose of this study is to report this institution's experience placing fiducial markers in prostate cancer patients who are on chronic antiplatelet or anticoagulant medication. Materials and Methods: From August 2015-March 2019 57 patients on chronic antiplatelet or anticoagulation therapy who were not cleared to stop these medications underwent transrectal ultrasound guided (TRUS) fiducial marker placement for SBRT/IGRT. All patients were monitored by a registered nurse during the procedure for prolonged bleeding that required staff to hold pressure to the area with a 4 × 4 gauze until it resolved. All patients were also called the following day to assess for ongoing bleeding events. Treatment planning CT scan confirmed the ideal geometry of the marker placement. Results: All 57 patients on antiplatelet or anticoagulant medication who underwent fiducial marker placement were discharged home the same day of the procedure. Four patients experienced persistent bleeding that required a nurse to hold prolonged pressure to the area. No patient experienced significant bleeding the following day or any untoward cardiovascular event. Conclusions: This series suggests the use of antiplatelet or anticoagulant medication is not an absolute contraindication to fiducial marker placement in patients undergoing SBRT or IGRT for prostate cancer. These patients should be closely monitored after the procedure for bleeding complications. Practitioners may consider the patient's medical comorbidities, risk factors for thromboembolism, and overall functional status as there is no standardized protocol for discontinuing anticoagulant or antiplatelet therapy for fiducial marker placement.