Objective: Clear cell ovarian carcinoma has a poorer prognosis compared with other histological subtypes.

Materials and Methods: The Multicenter Italian Trials in Ovarian Cancer (MITO) 9 study retrospectively assessed an Italian cohort of patients with clear cell ovarian cancer observed in the years 1991-2007 in 20 Italian centers.

Results: A total of 240 patients with ovarian cancer were analyzed. Forty-five percent of the patients had stage I disease. In 62.9%, clear cell histology was pure, whereas in the other cases, a mixed population was evident. Most of the cases underwent standard surgery, whereas in 7.1% of the patients, a fertility-sparing surgery was given. Lymphadenectomy was performed in 47.9% (115/240) of the patients (54.3% in stages I and II; 39.2% in advanced stage). Most of the patients were treated with platinum-based chemotherapy including paclitaxel in 52.9%. Disease-free survival was longer in patients undergoing lymphadenectomy at surgery (P = 0.0001), both in early stages (P = 0.0258) and in stage III and IV diseases (P = 0.0037). The impact of lymphadenectomy was also evident on overall survival in patients with advanced-stage disease. At multivariate analysis, lymphadenectomy (done vs not done) and stage (I and II vs III and IV) were independently associated with longer disease-free and overall survival, whereas front-line chemotherapy (with vs without taxanes) was not significant.

Conclusion: This analysis suggests that lymphadenectomy has a strong prognostic role for clear cell ovarian cancer influencing disease-free survival and overall survival. The addition of paclitaxel to platinum-based chemotherapy does not affect the outcome.