According to the results of a study recently published in JAMA Dermatology, patient age may be a contributing factor in determining SLNB recommendations in cases of thin melanomas.
“Patient age was shown to be an important discriminant of nodal positivity among patients with mitogenic tumors 0.50 to 0.75 mm and 0.76 to 1.0 mm and nonmitogenic tumors 0.50 to 0.75 mm,” wrote Andrew J. Sinnamon, MD, of the Hospital of the University of Pennsylvania, and colleagues. “Patients 65 years or older were shown to have a lower risk of nodal disease across risk groups, and patients younger than 40 years had a higher risk.”
The majority of melanoma diagnosed each year are category T1 tumors at 1.0 mm thickness or less, according to the study. Although these patients have good prognosis, the use of sentinel lymph node biopsy (SLNB) to identify occult nodal disease is controversial. Guidelines by the National Comprehensive Cancer Network for SLNB are based on the probability of identifying nodal disease. The procedure is not recommended in patients with a node positivity threshold lower than 5%.
In this study, the researchers wanted to identify indicators of lymph node metastasis in thin melanoma. For the retrospective cohort study, Sinnamon and colleagues used data from the National Cancer Database from 2010 to 2013. The study included 8,772 patients with clinical stage I 0.50- to 1.0-mm thick melanoma who underwent wide excision and surgical evaluation of regional lymph nodes.