Effect of Long-Term Hormonal Therapy (vs Short-Term Hormonal Therapy): A Secondary Analysis of Intermediate-Risk Prostate Cancer Patients Treated on NRG Oncology RTOG 9202

• Published in: International journal of radiation oncology, biology, physics Vol. 97; no. 3; pp. 511 - 515
• Main Authors: Mirhadi, Amin J., Zhang, Qiang, Hanks, Gerald E., Lepor, Herbert, Grignon, David J., Peters, Christopher A., Rosenthal, Seth A., Zeitzer, Kenneth, Radwan, John S., Lawton, Colleen, Parliament, Matthew B., Reznik, Robert S., Sandler, Howard M.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.03.2017
• Subjects: Adenocarcinoma; Aged; Aged, 80 and over; Androgen Antagonists - therapeutic use; Antineoplastic Agents, Hormonal - therapeutic use; Combined Modality Therapy - methods; Disease-Free Survival; Drug Administration Schedule; Hematology, Oncology and Palliative Medicine; Humans; Kaplan-Meier Estimate; Male; Middle Aged; Neoplasm Grading; Prostate-Specific Antigen - blood; Prostatic Neoplasms - blood; Prostatic Neoplasms - drug therapy; Prostatic Neoplasms - mortality; Prostatic Neoplasms - radiotherapy; Radiology; Radiotherapy, Conformal; Retrospective Studies; Risk; Survival Rate; Time Factors; Treatment Outcome
• ISSN: 0360-3016; 1879-355X; 1879-355X
• DOI: 10.1016/j.ijrobp.2016.11.002

NRG Oncology RTOG 9202 was a randomized trial testing long-term adjuvant androgen deprivation (LTAD) versus initial androgen deprivation only (STAD) with external beam radiation therapy (RT) in mostly high-risk and some intermediate-risk prostate cancer patients. RTOG 9408 found an overall survival (OS) advantage in patients with cT1b-T2b disease and prostate-specific antigen (PSA) <20 ng/mL, with benefit observed mostly among intermediate-risk patients. It was still unknown whether intermediate-risk patients would experience an additional survival benefit with LTAD; thus, we performed a secondary analysis to explore whether LTAD had any incremental benefit beyond STAD among the intermediate-risk subset of RTOG 9202. The study endpoints were OS, disease-specific survival (DSS), and PSA failure (PSAF). An analysis was performed for all patients enrolled in RTOG 9202 defined as intermediate-risk (cT2 disease, PSA<10 ng/mL, and Gleason score = 7 or cT2 disease, PSA 10-20 ng/mL, and Gleason score <7). This review yielded 133 patients: 74 (STAD) and 59 (LTAD). The Kaplan-Meier method was used to estimate OS; the cumulative incidence approach was used to estimate DSS and PSAF. A 2-sided test was used, with significance level defined to be .05. With over 11 years of median follow-up, 39 STAD patients were alive and 33 LTAD patients were alive. There was no difference in OS (10-year estimates, 61% STAD vs 65% LTAD; P=.53), DSS (10-year DSS, 96% vs 97%; P=.72), or PSAF (10-year PSAF, 53% vs 55%; P=.99) between groups. LTAD did not confer a benefit in terms of OS, DSS, or PSAF rates in the intermediate-risk subset in this study. Whereas the subset was relatively small, treatment assignment was randomly applied, and a trend in favor of LTAD would have been of interest. Given the small number of disease-specific deaths observed and lack of benefit with respect to our endpoints, this secondary analysis does not suggest that exploration of longer hormonal therapy is worth testing in the intermediate-risk prostate cancer subset.