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History of basal cell carcinomas tops future occurrence predictors

Having basal cell carcinomas during the 5 years before study enrollment was the biggest patient risk factor for future occurrences, while occupational sun exposure before age 30 and eczema history also were significant predictors in a recent study.

Researchers evaluated 1,131 participants (median age, 72 years; 97% men) during the 6-year Veterans Affairs Topical Tretinoin Chemoprevention Trial conducted at six locations. All patients had at least two previous keratinocyte carcinomas (KC), with a mean of 3.6 KCs in 5 years.

During a median follow-up of 3.6 years, 44% of participants developed new basal cell carcinomas (BCC). In multivariate analysis, patients who had more than five BCCs in the 5 previous years had an HR of 4.01 (95% CI, 3.02-5.31) compared with those who had fewer than two BCCs. Occupational sun exposure before age 30 also was a major predictor of BCC, even after controlling for later exposure or overall occupational exposure (HR=1.31; 95% CI, 1.04-1.64). Other risk factors were history of eczema (HR=1.54; 95% CI, 1.03-2.32), age (per decade HR=1.26; 95% CI, 1.14-1.40) and sunscreen use (SPF 15 or greater) on the face and ears during the week before study enrollment (HR=1.25; 95% CI, 1.01-1.54). Using sunscreen during the 6 months before enrollment was not correlated to risk.

“Basal cell carcinoma is a chronic disease once people have had multiple instances of it, because they are always at risk of getting more,” researcher Martin A. Weinstock, MD, PhD, professor of dermatology and epidemiology at Brown University, said in a news release.