Evaluating the Impact of Lead-Time Bias on the Observed Efficacy of Early Salvage Radiation Therapy in Prostate Cancer: A Post-Hoc Analysis of the RTOG 9601 Trial

6617 Background: Retrospective database studies have suggested that statins and vitamin D have a positive impact on prostate cancer survival and specifically in mCRPC patients (pt). Methods: We conducted a post-hoc analysis of individual pt data of mCRPC pts treated with abiraterone (AA) and/or Prednisone (P) on two randomized phase III clinical trials COU -AA-301 and COU-AA-302 to analyze the impact of statins and vitamin D in overall survival (OS). Statistical analyses were performed using the Kaplan Meier method and Independent predictors were investigated using Cox regression analysis. This study, carried out under YODA Project #2016-1136, used data obtained from the Yale University Open Data Access Project. Results: These two studies included 2280 patients (1340 treated with AA/P and 640 with P). Use of Statin + vitamin D was associated with a 38% reduction in mortality in the postdocetaxel setting and 32% in the predocetaxel setting in patients treated with abiraterone (Table 1 and 2). No significant reduction in the rate of skeletal-related events was seen in patients treated with vitamin D or statins. Conclusions: To our knowledge this is the first report suggesting the impact of vitamin D+statin in mCPRC treated with abiraterone. The potential benefits of vitamin D do not seem to be secondary to concomitant statin use in this population. Further studies are needed to confirm these results. [Table: see text][Table: see text]

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Adjuvant Versus Early Salvage Radiation Therapy for Men at High Risk for Recurrence Following Radical Prostatectomy for Prostate Cancer and the Risk of Death

Journal of Clinical Oncology ◽

10.1200/jco.20.03714 ◽

2021 ◽

pp. JCO.20.03714

Author(s):

Derya Tilki ◽

Ming-Hui Chen ◽

Jing Wu ◽

Hartwig Huland ◽

Markus Graefen ◽

...

Keyword(s):

Prostate Cancer ◽

Radiation Therapy ◽

Radical Prostatectomy ◽

Causal Effect ◽

Specific Antigen ◽

Study Cohort ◽

Adjuvant Radiation ◽

Salvage Radiation Therapy ◽

Risk Of Death ◽

The Impact

PURPOSE Adjuvant compared with early salvage radiation therapy (sRT) following radical prostatectomy (RP) has not been shown to reduce progression-free survival in randomized controlled trials. However, these trials might have missed a benefit in men with adverse pathology at RP given that these men were under-represented and immortal time bias might have been present; herein, we investigate this possibility. METHODS We evaluated the impact of adjuvant versus early sRT on all-cause mortality (ACM) risk in men with adverse pathology defined as positive pelvic lymph nodes (pN1) or pGleason score 8-10 prostate cancer (PC) and disease extending beyond the prostate (pT3/4). We used a treatment propensity score to minimize potential treatment selection bias when estimating the causal effect of adjuvant versus early sRT on ACM risk and a sensitivity analysis to assess the impact that varying definitions of adverse pathology had on ACM risk adjusting for age at RP, PC prognostic factors, site, and the time-dependent use of post-RP androgen deprivation therapy. RESULTS After a median follow-up (interquartile range) of 8.16 (6.00-12.10) years, of the 26,118 men in the study cohort, 2,104 (8.06%) died, of which 539 (25.62%) were from PC. After excluding men with a persistent prostate-specific antigen, adjuvant compared with early sRT was associated with a significantly lower ACM risk among men with adverse pathology at RP when men with pN1 PC were excluded (0.33 [0.13-0.85]; P = .02) or included (0.66 [0.44-0.99]; P = .04). CONCLUSION Adjuvant radiation therapy should be considered in men with pN1 or pGleason score 8 to 10 and pT3/4 PC given the possibility that a significant reduction in ACM risk exists.

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