No indication for performing sentinel node biopsy in melanoma patients with a Breslow thickness of less than 0.9 mm

In thin melanomas, the involvement of regional nodes is very uncommon. Rece nt sentinel node (SN) studies have confirmed the absence of positive region al lymph nodes in melanomas < 0.76 mm and a 5% positivity in melanomas betw een 1.0 and 1.99 mm. The chance of regional lymph node involvement-and ther efore whether it is relevant to perform the SN procedure-seems to depend on the Breslow thickness of the primary tumour. However, a Breslow thickness cut-off point has not yet been established. We evaluated a melanoma populat ion that had undergone an SN procedure to determine this point, so that the procedure can be restricted to a smaller group of patients in future. In a total of 348 patients with proven American joint Committee on Cancer (AJCC ) stages I or II cutaneous melanoma with a Breslow thickness <greater than or equal to> 0.5 mm the triple technique was used, consisting of preoperati ve visualization of the lymph channels from the initial site of the melanom a towards the SN by (dynamic) lymphoscintigraphy, intraoperative visualizat ion of those particular lymph channels and nodes with blue dye, and a gamma probe to measure accumulated radioactivity in radiolabelled lymph nodes, i n melanomas thinner than 0.90 mm, no positive SN was found (95% confidence interval 0-5%), This group consisted of 75 patients (22%), with a median fo llow-up of 31 months. Our data suggest that this procedure need no longer b e indicated for almost a quarter of the patient population, because the cut -off point for nodal involvement appears to be a Breslow thickness of 0.90 mm, (C) 2001 Lippincott Williams & Wilkins.