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Adjuvant radiation, androgen deprivation, and docetaxel for high-risk prostate cancer post-prostatectomy: Results of RTOG 0621.
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Background: Phase III trials have shown benefit in progression-free survival and in some cases overall survival with adjuvant radiation therapy (ART) in men with adverse pathologic findings at radical prostatectomy (RP). Despite ART, a high-risk group of patients has been defined with 50% risk of progression at 3 years, a risk factor for prostate cancer specific mortality. RTOG 0621 is a single-arm phase II trial that assessed whether addition of androgen deprivation (ADT) and docetaxel to ART would increase freedom from progression (FFP) at 3 years from 50% to ≥ 70% in these high-risk patients. Methods: Eligible subjects had prostatic adenocarcinoma who underwent RP with PSA nadir > 0.2 and Gleason score ≥ 7 or PSA nadir ≤ 0.2 with Gleason score ≥ 8 and ≥ pT3. Subjects received 6 months of ADT + RT to the pelvis with prostatic fossa boost to 66.6 Gy followed in one month with 6 cycles of docetaxel 75 mg/m2 every 21 days. The primary objective was to assess whether addition of ADT and docetaxel to ART results in FFP of ≥70% as defined as PSA < 0.4 ng/ml, and no clinical failure or death from any cause at 3 years. Multivariate logistic regression was used to model association of factors with the occurrence of FFP. Odds ratios and respective 95% confidence intervals were computed. Results: 76 patients with median age 62 meeting eligibility criteria were enrolled on the study. 3 year FFP was 71%, (95% CI:61-81%), p-value<0.001. In univariate and multivariate models, only post-RP PSA was statistically significantly associated with FFP. Two deaths occurred of which only 1 was related to prostate cancer. The most common significant chemotherapy side effects were peripheral neuropathy (12 grade 2 and 1 grade 3) and febrile neutropenia in 3 patients. Six subjects (8%) experienced late grade 3-4 treatment related toxicities. Conclusions: Addition of ADT and docetaxel to ART for men as high risk of failure despite ART alone following prostatectomy resulted in a significant improvement in FFP as compared to historical controls. Phase III trials assessing chemotherapy in this high-risk population are warranted. This work was supported by RTOG grant U10 CA21661 and CCOP grant U10 CA37422 from the NCI and Sanofi-Aventis. Clinical trial information: NCT00528866.
Abstracts by Mark Hurwitz:
- Meeting: 2015 Gastrointestinal Cancers Symposium | Abstract No: 376
Phase I trial of weekly cabazitaxel with concurrent intensity-modulated radiation therapy (IMRT) and androgen deprivation therapy (ADT) for the treatment of high-risk prostate cancer (PCa).Meeting: 2015 Genitourinary Cancers Symposium | Abstract No: 26
Tissue hyperthermia: Progress in the United States and elsewhere as assessed by clinical trials and PubMed reporting.Meeting: 2015 ASCO Annual Meeting | Abstract No: e22172