Stage IVB endometrial cancer: does applying an ovarian cancer treatment paradigm result in similar outcomes? A case-control analysis.

OBJECTIVE: The pattern of metastasis for Stage IV endometrial carcinoma (EC) is similar to that for ovarian carcinoma (OC), hence the goal of surgical management for both diseases is optimal cytoreduction (CRS) followed by adjuvant chemotherapy. The objective of this study is to evaluate overall survival (OS) and progression-free survival (PFS) in patients with advanced EC compared to a cohort of patients with OC matched for age and residual disease.
METHODS: Patients with Stage IVB EC treated with curative intent between the years of 1990-2006 were identified and data abstracted regarding demographics, surgical procedures, pathologic factors, and follow-up. Two patients with Stage IIIC OC were matched for each Stage IVB EC based on age and residual disease. Stage IVB EC patients with distant metastasis were excluded. All OC patients underwent primary CRS and received combination platinum based chemotherapy. PFS and OS were evaluated using Kaplan-Meier curves and log-rank analysis.
RESULTS: 55 patients with Stage IVB EC underwent primary CRS and adjuvant therapy with curative intent. Optimal CRS (<1 cm residual disease) was achieved in 87% (n=48). The most common histologic subtypes were serous (53%, n=29), endometrioid (44%, n=24) and clear cell (3%, n=2). Adjuvant therapy with curative intent included platinum based combination chemotherapy (60%, n=33), platinum based chemotherapy with radiation (25%, n=14), and radiation alone (15%, n=8) depending on the time period of treatment. Seven patients had residual disease >1 cm following CRS, 6 of whom received chemotherapy alone. Two-year OS for the entire cohort was 52 vs. 76% for patients with EC compared to OC (p=0.008). For suboptimal EC vs. OC patients was 33% vs. 66% for OC patients (p=NS). EC patients with optimal CRS had OS of 57% at 2 years compared to 82% for OC patients (p=0.02). Median PFS was 13 months vs. 20 months for all EC and OC patients, respectively (p=0.01). Using a Cox proportional hazards model, optimal CRS was associated with a survival advantage over suboptimal for EC patients with a hazard ratio of 2.4.
CONCLUSIONS: The treatment paradigm for advanced EC has undergone a drastic evolution from palliation to CRS and combination chemotherapy. Despite similarities in disease distribution and histology, OS for EC patients with intraperitoneal metastasis does not approach that of patients with advanced OC. Further research to identify the molecular characteristics of EC may identify important differences from OC and provide insight for the development of novel primary and salvage treatment strategies for patients with advanced EC.