Study to investigate the correlation between the number of sentinel lymph nodes and the incidence of micro-metastases

Abstract

Introduction: Sentinel lymph node (SLN) biopsy is a technique that identies micro-metastases within lymph nodes in the regional nodal basin. It is useful in the accurate staging of tumours such as skin malignancies because of the reliable pattern of lymphatic drainage. This study aims to investigate whether there is a correlation between the number of SLNs and the incidence of micro-metastases. Method: A retrospective review of data from 742 patients with metastatic melanoma who underwent SLN biopsy at The Christie Hospital from 2008 to 2019 was performed. Result: A total of 742 patients with 743 primary melanomas of the limbs were identi?ed. Fifty-three of 328 cases had micro-metastases with 1 SLN (16.2%) compared to 59/296 (19.9%) with 2 SLNs, 22/83 (26.5%) with 3 SLNs, 8/24 (33.3%) with 4 SLNs and 4/7 (57.1%) with 5 SLNs. The remaining 5 cases had 6 or more SLNs, but the incidences of micro-metastases were negligible. Conclusion: Our findings indicate that there is a direct correlation between the number of sentinel nodes harvested at the time of surgery and the incidence of micro-metastases in patients with cutaneous melanoma independent of other prognostic factors. We have found that the incidence of micro-metastases increases as the number of SLNs increase.