Frequency of level II and III axillary nodes metastases in patients with positive sentinel lymph nodes in melanoma: a multi-institutional study in Japan

Background: Axillary lymph node dissection (ALND) has been recommended to include levels I–III for melanoma patients who have evidence of metastasis in the axillary sentinel lymph node (SLN). The extent of the subsequent axillary dissection is in debate. The objective of this study was to determine the frequency of metastasis of level III nodes in addition to that of level II nodes in this setting. Methods: A multi-institutional retrospective study was undertaken in 14 melanoma treatment centers in Japan. Results: Between 2007 and 2012, 69 patients with involved axillary SLNs underwent a subsequent ALND and 55 underwent level I and II dissections. Level III metastatic nodes, which is our primary endpoint, were seen in only 1 patient (1.5 %). The level II metastatic rate was 4.4 %. Conclusions: Our study sample size was small, but melanoma patients with positive SLN rarely had level III disease, suggesting that level III dissection may be unnecessary. We also found that level II metastasis was not so frequent. More evidence is needed to standardize the extent of ALND and to identify the patients who would have the most benefit with undergoing level II dissection for positive axillary SLNs.