The role of complete lymph node removal in melanoma groin metastasis

This study investigated predictive factors of pelvic lymph node (LN) metastasis (cancer spread to the lymph nodes) and prognostic outcome of having pelvic LN metastasis. Researchers reported that pelvic metastases are associated with worse prognosis and pelvic LN complete removal should be considered in all cases.  

Sentinel lymph node biopsy (SLNB) is a procedure used to detect lymph node metastasis (spread of disease) in melanoma patients. Lymph node metastasis increases the risk of the cancer spreading to other areas of the body. Lymph node removal by surgery is the recommended treatment for patients with positive SLNB. However, the role of complete lymph node removal in improving patient survival remains unclear, especially when LN metastasis involves the groin. Post-surgery complications that affect long-term quality of life occur in up to 80% of pelvic LN removals.

The objective of this study was to investigate predictive factors for pelvic metastasis and the outcomes in patients with positive SLNB of the groin. This study included information on 740 patients with positive groin SLNB who underwent complete pelvic LN removal. The average follow-up period was 62.6 months. 26% of patients had positive non-SLNB nodes after LN removal, 12% of these in their pelvis.

Older patients had a 69% increase in the odds of pelvic LN metastasis and those with a primary tumor thicker than 4 mm  had a 60% increase. The odds of having pelvic LN metastasis increased 2.5 times in those patients with more than one positive sentinel lymph nodes.

5-year disease free survival (time from treatment until disease return) was 74.1% for patients with only SLN metastasis and 30% for patients who had pelvis metastasis. 5-year melanoma-specific survival (time from treatment until death due to melanoma) was 80.9% for SLN positive patients and 50% for patients with pelvic metastasis.

This study determined that patients with pelvic metastasis have worse prognosis. Pelvis metastasis removal should be considered in patients with positive SLNB in the groin, especially in those who are older, have thick tumors and more than two positive sentinel lymph nodes.