Correlation between MIB1-determined tumor growth fraction and incidence of tumor recurrence in early ovarian carcinomas.

PURPOSE: The decision concerning adjuvant therapy remains difficult in patients with very early stage ovarian carcinomas [Fédération Internationale de Gynécologie et d' Obstétrique (FIGO) Ia/b]. Therefore, we compared the MIB1-determined tumor growth fraction in archival tumor tissue with tumor recurrence and outcome of disease, and in relationship to other stages and clinical and morphological findings.

PATIENTS AND METHODS: Ninety-two patients were followed in early stages of ovarian carcinomas (FIGO I and II) with no tumor residuals and were analyzed for tumor recurrences and long-term overall survival (mean 6.0 years, median 5.5). Fifty-eight patients had stage I tumors, among these were 38 in the sub-stages Ia/b. Tumor growth fraction (MIB1) in tissues from primary surgery was compared with the status of patients and disease, histology, and immunohistochemistry for carcinoembryonic antigen (CEA), CA125, CA153, steroid hormone receptors, and angiogenesis (chisquare test, Kaplan-Meier and discriminant analyses).

RESULTS: Tumor-associated deaths occurred in 27 cases, tumor recurrences occurred in 35 cases. In contrast to the advanced stages of disease, the MIB1-determined tumor growth fraction outweighted all other parameters in the prediction of the course of disease (p < 0.001), followed by tumor grading (p = 0.001) and FIGO-substages (p = 0.026) in this retrospective study. Particularly in the very early stages, MIB1 predicted tumor recurrences in 84% of the cases (p < 0.001). Recurrences were not observed below a tumor growth fraction of 10% but prevailed in cases of more than 15%.

CONCLUSION: Our data suggest MIB1 as an interesting additional tool for the decision of adjuvant therapy in patients with very early stages of ovarian carcinomas, which should be tested in prospective trials.