Effect of lymphovascular space invasion on survival of stage I epithelial ovarian cancer.

OBJECTIVE To evaluate the effect of lymphovascular space invasion on survival of patients with early-stage epithelial ovarian cancer. METHODS A multicenter retrospective study was conducted for patients with stage IA-C epithelial ovarian cancer who underwent primary comprehensive surgery including lymphadenectomy. Histopathology slides for ovarian tumors were examined by gynecologic pathologists for the presence or absence of lymphovascular space invasion. Survival analysis was performed examining tumoral factors. RESULTS A total of 434 patients were included in the analysis. Lymphovascular space invasion was detected in 76 (17.5%) patients associated with histology (P=.042) and stage (P=.044). Lymphovascular space invasion was significantly associated with decreased survival outcomes (disease-free survival, 5-year rate 78.4% compared with 90.7%, P=.024 and overall survival, 84.9% compared with 93.2%, P=.031) in univariate analysis. In multivariate analysis, lymphovascular space invasion did not remain a significant variable for disease-free survival (hazard ratio [HR] 1.98, 95% confidence interval [CI] 0.97-3.97, P=.059) or overall survival (HR 2.41, 95% CI 0.99-5.85, P=.052). Lymphovascular space invasion was associated with increased risk of hematogenous and lymphatic metastasis (HR 4.79, 95% CI 1.75-13.2, P=.002) but not peritoneal metastasis (P=.33) in multivariate analysis. Among lymphovascular space invasion-expressing tumors, patients who received fewer than six cycles of postoperative chemotherapy had significantly poorer disease-free survival than those who received six or more cycles (HR 4.59, 95% CI 1.20-17.5, P=.015). CONCLUSION Lymphovascular space invasion is an important histologic feature to identify a subgroup of patients with increased risk of recurrence in stage I epithelial ovarian cancer. LEVEL OF EVIDENCE III.