Sun exposure and basal cell carcinomas in the nevoid basal cell carcinoma syndrome.

BACKGROUND: Nevoid basal cell carcinoma syndrome (NBCC) is an autosomal dominant multisystem disorder. Persons with the NBCC gene have varied susceptibility to basal cell carcinoma (BCC) development.

OBJECTIVE: We examined the anatomic site-specific distribution of BCCs and the relation between sun exposure and numbers of BCCs in NBCC cases.

METHODS: A questionnaire asking about lifetime sun exposure, sun behavior habits, and number of BCCs was sent to 16 families with NBCC evaluated between 1985 and 1991. The results were compared with previously published data for the general population.

RESULTS: In the general population, 88% of all BCCs in women and 86% in men occurred on the face, head, neck, and arms versus 59% in women with NBCC and 65% in men with NBCC. Of BCCs in the general population 9% and 12% occurred on the trunk versus 38% and 32% of BCCs in NBCC cases, in women and men, respectively. We did not observe a strong relation between numbers of BCCs and history of lifetime sun exposure.

CONCLUSION: The anatomic-site distribution of BCCs suggests that frequent sun exposure may not be essential for the development of BCCs in patients with NBCC. However, the observation that there are more tumors on sun-exposed areas suggests that exposure to the sun promotes the development of BCCs in patients with NBCC.