Cancer is found in one or both ovaries. Stage I is divided into stages IA, IB, and IC. In stage IA, cancer is found inside a single ovary. In stage IB, cancer is found inside both ovaries. In stage IC, cancer is found inside one or both ovaries and one of the following is true: (1) cancer is also found on the outside surface of one or both ovaries; or (2) the capsule (outer covering) of the ovary has ruptured (broken open); or (3) cancer cells are found in the fluid of the peritoneal cavity (the body cavity that contains most of the organs in the abdomen) or in washings of the peritoneum (tissue lining the peritoneal cavity).