Stage IA ovarian cancers: comparison of sonographic findings and histopathologic types between patients with normal and elevated serum cancer antigen 125 levels.

OBJECTIVES: The purpose of this study was to compare sonographic findings and histopathologic types of stage IA ovarian cancers between groups with normal and elevated cancer antigen 125 (CA-125) levels.

METHODS: Between 2000 and 2009, 146 stage IA ovarian cancers were treated surgically (85 invasive and 61 borderline, 73 self-referred with tumor-related symptoms, 20 self-referred with nonspecific symptoms, 52 identified through screening, and 1 other). Of these, 87 cases (60%) had normal serum CA-125 levels (<35 U/mL). Their pre-operative sonographic findings and histopathologic types were compared to those of cases with elevated CA-125 levels.

RESULTS: Statistically significant differences were found between the proportions of patients with elevated CA-125 levels in groups having tumors with maximal diameters of less than 20 cm and at least 20 cm (P = .03) and groups having tumors with less than 50% and 50% to 80% solid components (P = .02). In the group with normal CA-125 levels, we found predominantly mucinous adenocarcinoma in multilocular cysts with less than 50% solid components (25 cases), and clear cell adenocarcinoma in unilocular cysts with less than 50% solid components (12 cases), whereas in the group with elevated CA-125 levels, mucinous adenocarcinoma in multilocular cysts with less than 50% solid components (19 cases) and endometrioid adenocarcinoma in solid tumors (≥80% solid components) were predominant (5 cases).

CONCLUSIONS: Stage IA ovarian cancers with normal CA-125 levels tend to be smaller, have less solid components, and have a slightly different distribution of histopathologic types than cancers with elevated CA-125 levels.