Burden of Metastatic Castrate Naive Prostate Cancer Patients, to Identify Men More Likely to Benefit from Early Docetaxel: Further Analyses of CHAARTED and GETUG-AFU15 Studies

International audience; BACKGROUND:Docetaxel (D) at the time of starting androgen deprivation therapy (ADT) for metastatic castrate naive prostate cancer shows a clear survival benefit for patients with high-volume (HV) disease. It is unclear whether patients with low-volume (LV) disease benefit from early D.OBJECTIVE:To define the overall survival (OS) of aggregate data of patient subgroups from the CHAARTED and GETUG-AFU15 studies, defined by metastatic burden (HV and LV) and time of metastasis occurrence (at diagnosis or after prior local treatment [PRLT]).DESIGN, SETTING, AND PARTICIPANTS:Data were accessed from two independent phase III trials of ADT alone or ADT+D-GETUG-AFU15 (N=385) and CHAARTED (N=790), with median follow-ups for survivors of 83.2 and 48.2 mo, respectively. The definition of HV and LV disease was harmonized.OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS:The primary end point was OS.RESULTS AND LIMITATIONS:Meta-analysis results of the aggregate data showed significant heterogeneity in ADT+D versus ADT effect sizes between HV and LV subgroups (p=0.017), and failed to detect heterogeneity in ADT+D versus ADT effect sizes between upfront and PRLT subgroups (p=0.4). Adding D in patients with HV disease has a consistent effect in improving median OS (HV-ADT: 34.4 and 35.1 mo, HV-ADT+D: 51.2 and 39.8 mo in CHAARTED and GETUG-AFU15, respectively; pooled average hazard ratio or HR (95% confidence interval [CI]) 0.68 ([95% CI 0.56; 0.82], p