Prognostic importance of degree of differentiation and cyst rupture in stage I invasive epithelial ovarian carcinoma

Background Previous studies on prognostic factors in stage I invasive epithelial ovarian carcinoma have been too small for robust conclusions to be reached. We undertook a retrospective study in a large international database to identify the most important prognostic variables. Methods 1545 patients with invasive epithelial ovarian cancer (International Federation of Gynaecology and Obstetrics [FIGO] stage I) were included. The records of these patients were examined and data extracted for univariate and multivariate analysis of disease-free survival in relation to various clinical and pathological variables. Findings The multivariate analyses identified degree of differentiation as the most powerful prognostic indicator of disease-free survival (moderately vs well differentiated hazard ratio 3.13 [95% CI 1.68-5.85], poorly vs well differentiated 8.89 [4.96-15.9]), followed by rupture before surgery (2.65 [1.53-4.56]), rupture during surgery (1.64 [1.07-2.51]), FIGO 1973 stage Ib vs Ia 1.70 [1.01-2.85]) and age (per year 1.02 [1.00-1.03]). When the effects of these factors were accounted for. none of the following were of prognostic value: histological type, dense adhesions, extracapsular growth, ascites, FIGO stage 1988, and size of tumour. Interpretation Degree of differentiation, the most powerful prognostic indicator in stage I ovarian cancer, should be used in decisions on therapy in clinical practice and in the FIGO classification of stage I ovarian cancer. Rupture should be avoided during primary surgery of malignant ovarian tumours confined to the ovaries.