ORLANDO—Adding short-term androgen deprivation therapy (STADT) to radiotherapy does not improve overall survival (OS) among men with intermediate-risk prostate cancer (IRPC), according to data from the prospective, randomized phase 3 PCS III clinical trial (Abstract 5), presented during the 2015 Genitourinary Cancers Symposium.1
“In intermediate-risk prostate cancer, the use of short-term androgen deprivation therapy in association with prostate radiotherapy even at lower doses, leads to a superior biochemical control and disease-free survival as compared to dose-escalated prostate radiotherapy alone,” reported lead study author Abdenour Nabid, MD, of the Centre Hospitalier Universitaire de Sherbrooke in Sherbrooke, Quebec, Canada. “However, these outcomes did not translate into improved overall survival.”
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A total of 600 patients with IRPC were enrolled between December 2000 and September 2010; 200 patients were randomly assigned to each of three study arms: STADT with prostate radiotherapy (70 Gy/7 weeks; Arm 1); STADT with prostate radiotherapy (76 Gy/7.5 weeks; Arm 2); and prostate radiotherapy alone (76 Gy/7.5 weeks; Arm 3). Radiotherapy delivered in 2 Gy fractions began 4 months after STADT was initiated.
“At a median follow-up of 75.4 months, biochemical failure had occurred in 84 (14%) patients (arms 1 to 3: 12.5%, 8.0%, 21.5%) with statistically significant differences between arm 1 and 3 (P=0.023) and arm 2 and 3 (P<0.001),” Dr. Nabid said. “There was no significant difference between arm 1 and 2.”
There were also no statistically significant differences in 5-year or 10-year OS between study arms.
A total of 113 (18.8%) patients died but only 6 (1%) deaths were attributed to prostate cancer.
- Nabid A, Carrier N, Vigneault E, et al. Place of short-term androgen deprivation therapy in intermediate-risk prostate cancer treated with radiotherapy: A phase III trial. 2015 Genitourinary Cancers Symposium. Abstract 5.