Association of Lymphadenectomy and Survival in Stage I Ovarian Cancer Patients
To estimate the survival impact of lymphadenectomy in women diagnosed with clinical stage I ovarian cancer. Demographic and clinicopathologic information were obtained from the Surveillance, Epidemiology and End Results Program between 1988 and 2001. Data were analyzed using Kaplan-Meier methods and Cox proportional hazards regression. A total of 6,686 women had clinical stage I ovarian cancer (median age 54 years, range 1-99). Of this total, 75.9% of patients were Caucasian, 8.3% were Hispanic, 5.8% were African American, and 7.3% were Asian. Epithelial tumors were present in 85.8% of the women, and 2,862 (42.8%) patients underwent lymphadenectomy. Patients aged 50 years or more were less likely to undergo lymphadenectomy compared with their younger cohorts (39.8% compared with 60.2%, P<.001). Only 32.7% of African-American women had lymphadenectomy compared with 42.7% of Caucasian women, 47.2% of Hispanics, and 48.8% of Asians (P<.001). Lymphadenectomy was associated with improved 5-year disease-specific survival of all patients from 87.0% to 92.6% (P<.001). More specifically, lymphadenectomy improved the survival in those with non-clear cell epithelial ovarian cancer (85.9% to 93.3%, P<.001) but not in those with clear cell carcinoma, germ cell tumors, sex cord stromal tumors, and sarcomas. Moreover, the extent of lymphadenectomy (0 nodes, less than 10 nodes, and 10 or more nodes) increased the survival rates from 87.0% to 91.9% to 93.8%, respectively (P<.001). On multivariable analysis, the extent of lymphadenectomy was a significant prognostic factor for improved survival, independently of other factors such as age, stage, histology, and grade of disease. Our data suggest that women with stage I non-clear cell ovarian cancers who underwent lymphadenectomy had a significant improvement in survival. II.