HORMONAL THERAPY SUPPORTED IN ADVANCED PROSTATE CANCER

Emma Hitt, PhD

Medscape Medical News 2003. © 2003 Medscape

June 2, 2003 (Chicago) - Ten-year follow-up data from the Radiation Therapy Oncology group (RTOG) protocol 85-31 study suggest that adjuvant androgen suppression significantly reduces rates of local failure, distant metastases, biochemical disease-free progression, and increases absolute survival.

Miljenko V. Pilepich, MD, principal investigator for the RTOG study and director of the Department of Radiation Oncology at St. Joseph Mercy Health System in Ann Arbor, Michigan, presented the data here at the 39th annual meeting of the American Society of Clinical Oncology on Saturday.

RTOG 85-31 was designed to evaluate the effectiveness of adjuvant androgen suppression using goserelin in patients with an unfavorable prognosis of carcinoma of the prostate treated with definitive radiotherapy. Patients included those in clinical stage T3 or those with regional lymphatic involvement.From 1987 to 1992, 977 patients were randomized to receive either radiotherapy and adjuvant goserelin (Arm I) or radiotherapy alone followed by observation and application of goserelin at the time of relapse (Arm II). In Arm I, the drug was started during the last week of radiation therapy and was to be continued indefinitely or until signs of progression. As of December 2002, the median follow-up reached 7.3 years for all patients and 10 years for live patients. Adjuvant androgen suppression resulted in significant improvement in all end points measured, Dr. Pilepich and colleagues found. At 10 years, 23% of those receiving goserelin compared with 39% of those receiving radiation therapy alone experienced local failure (P < .0001). Similarly, 25% of those receiving goserelin vs. 39% of those receiving radiation therapy alone experienced distant metastases (P < .0001); and 30% vs. 9% achieved prostate-specific antigen levels less than 1.5 ng/mL (P < .0001).

"Treatment remained statistically significant on multivariate analysis for all endpoints," the researchers conclude. Variables included nodal status, Gleason score, radical prostatectomy, and stage. Absolute survival was 53% vs. 38% in the hormonal vs. radiation therapy-only group, respectively (P < .0043). Deaths from prostate cancer were also significantly lower in the group receiving hormonal therapy (P = .0053). However, when the groups were subdivided into patients with a Gleason score of 2 to 6 and compared with those with a Gleason score of 7 or more, patients with a lower Gleason score did not show a significant difference in absolute survival (P = 0.32) in response to hormonal therapy. In contrast, hormonal therapy did benefit those with a higher score (P = .042), Dr. Pilepich noted during his presentation.

"This study with adequate follow-up shows that overall survival is improved with long-term hormone therapy," Howard Sandler, MD, associate professor and associate chair of radiation oncology in the University of Michigan Health System told Medscape.

According to Dr. Sandler, more and more emerging evidence suggests that for patients with poor-prognosis, high-risk localized prostate cancer, there's a life-prolonging benefit from long-term androgen suppression.