[Prognosis after sentinel node biopsy in malignant melanoma]

Abstract

Introduction: Sentinel node biopsy (SNB) is used in patients with cutaneous malignant melanoma (MM) to detect subclinical spread to the regional lymph nodes, after which a radical lymph node dissection can be performed. Since 2001, the Department of Plastic Surgery, Roskilde Amts Sygehus, has used SNB routinely in patients with cutaneous MM who have a statistical risk of at least 10% of harbouring subclinical lymph node metastasis.

Materials and methods: In the four-year period from 2001 to 2004, 248 consecutive patients with primary MM underwent SNB at the time of radical surgery for their MM. If metastatic spread was found in the removed sentinel node, a radical lymph node dissection was performed shortly afterward. All patients were followed up after their operation in the department's outpatient clinic.

Results: Regional lymph node metastatic spread was found by SNB in 32% of the patients. At radical lymph node dissection, further metastatic lymph nodes were found in 24% of the dissected cases. The median follow-up time was 21 months (range 1-51 months). 7% of SN-negative cases developed recurrence during follow-up, in contrast to 23% of the SN-positive cases. The median time to recurrence was 14 months. The two-year and four-year disease-free survival rates were 93% and 85% in the SN-negative group and 73% and 55% in the SN-positive group, respectively. Risk factors for recurrence were: extracapsular SN growth, more than one metastatic SN and further lymph node metastases being found by formal node dissection. 18% of the SN-positive patients died during the follow-up period, in contrast to 3% of the SN-negative cases. The MM-specific two-year and four-year survival rates were 84% and 64% in the SN-positive group and 99% and 97% in the SN-negative group, respectively.

Conclusion: Sentinel node biopsy is a procedure that detects MM patients who have a very high risk of recurrence and death by MM within a few years after primary treatment. SNB status is a very strong prognostic factor, and SN-positive cases should be followed carefully.