Mapping sentinel lymph nodes in early-stage ovarian cancer (MELISA) trial - a further step towards lymphadenectomy replacement

Abstract

Objective: Sistematic pelvic and para-aortic lymphadenectomy is part of the staging surgery for early-stage epithelial ovarian cancer, with no therapeutic value. The Mapping Sentinel Lymph Nodes In Early-Stage Ovarian Cancer (MELISA) trial prospectively assessed the SLN detection rate and the diagnostic accuracy of the SLN mapping technique in patients with early-stage epithelial ovarian cancer.

Methods: This prospective, single-arm study included patients diagnosed with early-stage epithelial ovarian cancer (FIGO stages I and II), via either primary surgery or re-staging surgery. SLN mapping was performed by injecting 0.2 mL of 37-mBq ^99mTc-nanocoloid albumin and 2 mL of 2.5 mg/mL indocyanine green into the infundibulopelvic and utero-ovarian ligaments. After removal of SLNs, a complete systematic pelvic and para-aortic lymphadenectomy was performed. SLN Ultrastaging analysis was applied. The primary outcome was the overall SLN detection rate, either with one or both tracers. Secondary outcomes were the diagnostic accuracy of detecting lymph node metastases and factors that may influence SLN detection.

Results: Thirty patients were included. SLNs were identified in 27 patients (90%). Detection rates in primary and re-staging surgery were 89% and 92%, respectively. Para-aortic drainage was the predominant lymphatic spread, observed in 26 of 27 patients. Ultrastaging pathologic reports listed 1 SLN with macrometastasis, 1 with micrometastasis, and 5 with isolated tumor cells; the sensitivity of SLN mapping was 100%, with a false-negative rate of 0%. Univariate analysis showed a nonsignificant higher proportion of patients with uterine fibroids, adenomyosis, and endometriosis (100%, 67%, 67%, respectively) in patients in whom SLNs were not detected.

Conclusion: SLN mapping has a high detection rate (90%) and is an accurate technique for detecting lymph node involvement in early-stage epithelial ovarian cancer. SLN mapping is a potential alternative to systematic lymphadenectomy to reduce associated morbidity, but further research is needed to evaluate the impact of SLN mapping on oncologic outcomes and its cost-effectiveness.

Keywords: Lymphatic mapping; Ovarian cancer; Sentinel lymph node.