Different Patterns of Disease Spread between Advanced-Stage Type I and II Epithelial Ovarian Cancer

Two types of epithelial ovarian carcinoma (EOC) have been recently distinguished. Type I comprises low-grade serous, endometrioid and clear-cell tumors. High-grade endometrioid and serous tumors belong to type II. The aim of this study was to compare patterns of disease spread in advanced-stage type I and II EOCs at primary surgery.

Surgical and pathological data of 233 patients with advanced-stage EOCs were collected, 42 with type I and 191 with type II. The two groups were compared for tumor localization at primary surgery. Intraoperative mapping of ovarian cancer (IMO) was used to assess tumor dissemination.

Tumor involvement was significantly higher in the type II group for the following: peritoneum (68.1 vs. 40.5%, p < 0.001), pouch of Douglas (60.2 vs. 40.5%, p = 0.06), vesicouterine ligament (40.8 vs. 19%, p = 0.027), diaphragm (45.0 vs. 11.9%, p < 0.001), serosa of liver (17.2 vs. 4.8%, p = 0.05), omentum (81.1 vs. 59.5%, p = 0.007), mesentery (42.9 vs. 16.7%, p = 0.005), pleural effusions (19.4 vs. 4.6%, p = 0.01) and ascites (60.7 vs. 21.4%, p < 0.001). IMO levels were different between the two groups (p = 0.001).

This study provides clinical evidence in favor of the dualistic model of carcinogenesis, since types I and II are characterized by different findings at primary surgery.