Multi-Modal Approach to Treat High-Risk Prostate Cancer Safe and Effective

Chicago—During a poster session at the 2017 ASCO Annual Meeting, Stephanie Rice, MD, and colleagues reported long-term results of a prospective, phase II study of 2 years of androgen deprivation therapy (ADT), 45 Gy bone marrow sparing pelvic radiation, Cs-131 brachytherapy boost (85 Gy), and four cycles of adjuvant docetaxel (75 mg/m2 every 21 days plus prednisone) in high-risk, localized prostate cancer. The poster was titled Long-Term Results of a Prospective Phase II Study of Androgen Deprivation Therapy, External Radiation, Cs-131 Brachytherapy and Adjuvant Docetaxel in High-Risk Prostate Cancer.

The study enrolled 38 patients from 2006 through 2014. Based on Common Terminology Criteria for Adverse Events, version 3.0 criteria, both acute hematologic and acute and chronic gastrointestinal and genitourinary toxicities were scored. Biochemical recurrence was defined as a nadir plus a 2 rise in prostate-specific antigen (PSA). Actuarial freedom from PSA failure and overall survival were calculated using SPSS Statistics v24. Median Gleason score was 8 and median PSA was 11.2.

Of the 38 enrolled patients, median age was 62 years (range, 45-82 years). All protocol specified treatments were completed by 82% of the study participants; 84% completed all four cycles of docetaxel. Median follow-up was 44 months (range, 3.4-118 months). At the median follow-up, the actuarial freedom from PSA failure was 86%; the 5-year overall survival rate was 80%. Acute grade ≥2 gastrointestinal toxicity rate was 12.5% and the rate of acute genitourinary toxicity was 21.9%. Chronic grade ≥2 gastrointestinal and genitourinary toxicity rates were 3.1% and 3.1%, respectively. Grade 4 hematologic toxicity was experienced by 10 patients in the docetaxel group (25.6%). There were no grade 5 toxicities.

In summary, the researchers said, “We found this aggressive multi-modal approach to be feasible, safe, well-tolerated, and effective. It does not appear that bone marrow sparing pelvis radiation decreases hematologic toxicity. Cs-131, with its 9.7-day half-life, does not appear to increase acute or late toxicity. These data build upon the ASCENDE-RT and RTOG 0521 trials that demonstrate the added benefits of brachytherapy boost and adjuvant docetaxel, respectively, in high-risk prostate cancer.”

Source: Rice S, Le GK, Hussain A, et al. Long-term results of a prospective phase II study of androgen deprivation therapy, external radiation, cs-131 brachytherapy, and adjuvant docetaxel in high-risk prostate cancer. Abstract of a poster presented at the 2017 American Society of Clinical Oncology, June 5, 2017, Chicago, Illinois.