Impact of lympho‐vascular space invasion on tumor characteristics and survival outcome of women with low‐grade serous ovarian carcinoma

Background and Objectives To examine association of lympho‐vascular space invasion (LVSI) with clinico‐pathological factors and to evaluate survival of women with low‐grade serous ovarian carcinoma containing areas of LVSI. Methods This is a multicenter retrospective study examining consecutive cases of surgically treated stage I‐IV low‐grade serous ovarian carcinoma (n = 178). Archived histopathology slides for the ovarian tumors were reviewed, and LVSI was scored as present or absent. LVSI status was correlated to clinico‐pathological findings and survival outcome. Results LVSI was seen in 79 cases (44.4%, 95% confidence interval [CI] 37.1‐51.7). LVSI was associated with increased risk of omental metastasis (87.0% vs 64.9%, odds ratio [OR] 3.62, P = 0.001), high pelvic lymph node ratio (median 12.9% vs 0%, P = 0.012), and malignant ascites (49.3% vs 32.6%, OR 2.01, P = 0.035). On multivariable analysis, controlling for age, stage, and cytoreductive status, presence of LVSI in the ovarian tumor remained an independent predictor for decreased progression‐free survival (5‐year rates 21.0% vs 35.7%, adjusted‐hazard ratio 1.57, 95%CI 1.06‐2.34, P = 0.026). LVSI was significantly associated with increased risk of recurrence in lymph nodes (OR 2.62, 95%CI 1.08‐6.35, P = 0.047). Conclusion LVSI in the ovarian tumor is associated with adverse clinico‐pathological characteristics and decreased progression‐free survival in women with low‐grade serous ovarian carcinoma.