Research in context
Evidence before this study
We did an extensive search of PubMed for studies comparing complete lymph node dissection with observation for patients with melanoma with micrometastases in the sentinel lymph nodes. Search terms were “micrometastases AND SLNB AND CLND AND melanoma”. There were no date or language restrictions to the search. Retrospective, non-randomised studies reported data in patients with melanoma that are in line with our analyses. A prospective, randomised non-inferiority phase 3 trial in patients with breast cancer found no difference in disease-free or overall survival between patients who did and did not have complete lymph node dissection. We also identified a couple of randomised controlled trials comparing elective lymph node dissection with observation in the era before sentinel lymph node biopsy. These studies did not support superiority of elective lymph node dissection compared with observation.
Added value of this study
To our knowledge, this is the first randomised controlled trial comparing complete lymph node dissection and observation in patients with micrometastasis in the sentinel lymph node in melanoma. By contrast with the initial assumption that complete lymph node dissection is superior to observation, no significant difference was found in distant metastasis-free survival, recurrence-free survival, or overall survival with complete lymph node dissection compared with observation. Moreover, the adverse events profile was less favourable for complete lymph node dissection compared with observation.
Implications of all the available evidence
Overall, these findings did not show a benefit of complete lymph node dissection compared with observation in patients with melanoma and micrometastases in the sentinel lymph node. Therefore, complete lymphadenectomy should not be recommended in patients with melanoma with micrometastasis, at least in those with single cells or micrometastases of 1 mm diameter or less, who were the majority of patients in our study.