Objectives The objective of this study was to estimate the prevalence and prognostic impact of lymphadenectomy and lymph node involvement in patients with ovarian clear cell carcinoma (OCCC) grossly confined to the ovary.

Methods Patients with a diagnosis of OCCC grossly confined to the ovary were identified from Surveillance, Epidemiology, and End Results program from 1988 to 2007. Only surgically treated patients were included. Statistical analysis using Student t test, Kaplan-Meier survival methods, and Cox proportional hazards regression were performed.

Results One thousand eight hundred ninety-seven patients with OCCC who have undergone surgical treatment and deemed at time of the surgery to have disease grossly confined to the ovary were included: 538 (28.3%) had no lymphadenectomy (LND −1), and 1359 (71.7%) had lymphadenectomy. Of the 1359 patients who had lymphadenectomy, 1298 (95.5%) were International Federation of Gynecology and Obstetrics (FIGO) surgical stage I (LND +1), and 61 (4.5%) were upstaged to FIGO stage IIIC due to nodal metastasis (LND +3C). The 5-year disease-specific survival was 84.9% for LND −1, 88.0% for LND +1, and 65.0% for LND +3C (P < 0.001). Among those with histologically negative lymph nodes, the 5-year disease-specific survival was 85% for patients with 1 to 10 nodes removed, and 91% for those with more than 10 nodes removed (P = 0.054). On multivariate analysis after controlling for stage, age, and race, lymph node metastasis was an independent predictor of poor disease-specific survival (hazard ratio, 3.1; 95% confidence interval, 1.86–5.28; P < 0.001). On other hand, there was a trend toward an improved survival when more extensive lymphadenectomy is performed in patients with histologically negative nodes (1–10 vs >10 nodes), but it did not reach statistical significance (hazard ratio, 0.71; 95% confidence interval, 0.49–1.02; P = 0.064).

Conclusions Lymph node metastasis was uncommon in patients diagnosed with OCCC grossly confined to the ovary; however, patients with positive nodes were more likely to die compared to those with negative nodes. More extensive lymphadenectomy plays an important role in providing accurate staging and prognostic information.