Influence of Residual Tumor on Outcome in Ovarian Cancer Patients with FIGO Stage IV Disease: an Exploratory Analysis of the AGO-OVAR (Arbeitsgemeinschaft Gynaekologische Onkologie Ovarian Cancer Study Group)

Background: One of the most important prognostic factors in advanced ovarian cancer is the macroscopic absence of residual tumor after primary surgery. The impact of surgical outcome on the survival of patients with International Federation of Gynecology and Obstetrics (FIGO) stage IV disease is less clear and is the subject of this study.

Methods: Surgical and survival data were documented throughout the multicenter prospective randomized phase III trials of the AGO-OVAR (OVAR-3/-5/-7) and were used for this exploratory analysis. In these studies, 573 patients with FIGO stage IV disease were first operated, then randomized and homogenously treated with a combination therapy comprising the intravenous application of platinum and paclitaxel.

Results: The median progression-free survival and overall survival of patients with stage IV ovarian cancer were 12.6 and 26.1 months, respectively. Multivariable Cox regression analysis for overall survival revealed that residual tumor, mucinous histological type, multiple sites of metastases, and Eastern Cooperative Oncology Group performance status were statistically significant prognostic variables. Whereas patients with macroscopically complete resection had a statistically significant improved outcome, patients with residual disease of 0.1-1 cm and patients with residual tumor of >1 cm showed similar outcome.

Conclusions: Macroscopically complete resection in FIGO stage IV disease, irrespective of the site of distant tumor spread, is an important prognostic factor and the only prognosticator amenable to improvement by therapy. Our results suggest possible advantages of a reasonable attempt at complete cytoreduction even in FIGO stage IV disease. In addition, tumor biology could be an important factor for achieving complete resection.