Extremity nevus count is a helpful clinical marker in risk-stratifying individuals for basal cell carcinoma (BCC) and melanoma on all body sites, according to a recent study. Researchers evaluated prospective cohorts of 176,317 women (the Nurses' Health Study, 1986-2012 and the Nurses’ Health Study 2, 1989-2013) and 32,383 men (Health Professionals Follow-up Study, 1986-2012). Information on nevus count (none, 1-5, 6-14, ≥15) on the extremity was collected at baseline. They found:
- There were 1,704 incident cases of melanoma, 2,296 incident cases of squamous cell carcinoma (SCC), and 30,457 incident cases of BCC, with a total of 4,655,043 person-years for melanoma and 4,267,708 person-years for keratinocyte cancers.
- The presence of an extremity nevus was associated with an increased risk of melanoma in all anatomic areas and increased risk of BCC.
- Individuals with ≥15 nevi had the highest risk of melanoma and BCC compared to those without any extremity nevi (melanoma hazard ratio 2.79; BCC HR 1.40).
- No significant association was observed for SCC.
Wei EX, Li X, Nan H. Extremity nevus count is an independent risk factor for basal cell carcinoma and melanoma, but not squamous cell carcinoma. [Published online ahead of print January 31, 2019]. J Am Acad Dermatol. doi:10.1016/j.jaad.2018.09.044.