The addition of paclitaxel to doxorubicin and cisplatin and volume-directed radiation does not improve overall survival (OS) or long-term recurrence-free survival (RFS) in advanced endometrial cancer (EC): A randomized phase III NRG/Gynecologic Oncology Group (GOG) study

Objectives: To determine if the addition of paclitaxel (P) to cisplatin and doxorubicin (CD) following surgical debulking and volume-directed radiation therapy improved long-term, recurrence-free survival (RFS) and overall survival (OS) in patients with advanced-stage endometrial cancer (EC). Methods: Prospective, randomized GOG trial comparing (CD) (50 mg/m²)/(45 mg/m²) +/− (P) (160 mg/m²) following volume-directed radiation and surgery in advanced EC. A Kaplan-Meier (KM) analysis characterized the relationship between treatment arms and the OS outcome, a log-rank test assessed the independence of treatment with the OS outcome, and the treatment effect on estimated OS was determined using a Cox proportional hazards (PH) model stratified by stage. The PH assumption was assessed using a test of interaction between treatment variable and the natural logarithm of survival time. Adverse events, regardless of attribution, were graded. Results: Since initial publication, 60 deaths occurred, leaving 311 patients alive with 290 (93.8%) recurrence- free. There was no significant decrease in the risk of recurrence or death associated with the CDP treatment regimen stratified for stage (p = 0.14, one-tail). The exploratory analysis for OS and the corresponding homogeneity tests for different effects across subgroups revealed only EFRT and EFRT & GRD status to have significantly different treatment effects (p = 0.027 and p = 0.017, respectively). Second primary malignancies were identified in 17/253 (6.4%) and 19/263 (7.0%) of patients treated with CD and CDP respectively. Breast (2.4%) followed by colon (1%) were the two cancers most frequently diagnosed in this setting. Conclusion: No significant difference between treatment arms was identified. Subgroup analysis both in the initial and current reports demonstrated a trend towards improved RFS and OS in patients treated with CDP and EFRT. This long-term analysis of outcomes also identified the necessity of providing on-going cancer screening to patients enrolled in trials.