Kavita Mariwalla, MD
Dr. Mariwalla is the Director of Dermatologic Surgery, Continuum Cancer Centers of New York, New York.
Dr. Mariwalla reports no conflicts of interest in relation to this post.
On July 9, the American Society of Clinical Oncology (ASCO) released recommendations for the use of the sentinel lymph node (SLN) biopsy in patients with melanoma (Journal of Clinical Oncology). The SLN typically is the first draining lymph node to which melanoma cells are most likely to spread, and a positive node certainly has implications for staging. However, sending a patient to have this node mapped has been very inconsistent among practitioners. It also comes at a risk: an additional procedure in the operating room and the chance of possible lymphedema in the area where the node was harvested.
In the dermatology literature, melanoma lesions with a depth of 0.75 mm and a high mitotic index have been considered for SLN biopsy. The ASCO guidelines differ. For thin melanomas (<1 mm) there was not enough evidence to recommend routine SLN biopsy, according to the ASCO panel based on a review of 73 studies over the last 2 decades. The panel also recommended that patients with melanoma tumors with a Breslow thickness of 1 to 4 mm should have the SLN procedure performed. The panel further stated that SLN biopsy may be beneficial for thick tumors (Breslow thickness >4 mm), though few studies focus on it with melanoma at this stage.
What’s the issue?
Although these guidelines are helpful, they do not provide definitive guidance regarding SLN for thin melanomas. For dermatologists, this topic has been consistently debated, leaving the practitioner in a dilemma, especially in the age of the Internet when patients with melanoma have a wealth of information to look at online. The fact remains that as a medical community we are conflicted on what to do for thin melanomas. Invariably the debate arises in the office setting as it did for me the other day. I diagnosed a 38-year-old woman with a 0.68-mm thick melanoma with a high mitotic index and brisk lymphocytic response on biopsy. She has a 7-month-old baby and 2-year-old toddler at home. Knowing the literature, in this case would you send her for SLN?