In the powerful sunlight of July, newly published results from a large study of people at high risk for basal cell carcinoma support the emerging view of the nation's most common cancer as a chronic ailment that often repeatedly afflicts older people but for which the seeds may be planted in youth. The research also found a new association with eczema.
"Basal cell carcinoma is a chronic disease once people have had multiple instances of it, because they are always at risk of getting more," said Dr. Martin Weinstock, professor of dermatology in the Warren Alpert Medical School of Brown University, who practices at the Providence Veterans Affairs Medical Center. "It's not something at the moment we can cure. It's something that we need to monitor continually so that when these cancers crop up we can minimize the damage."
Dermatologists hold out hope for a medication that will help prevent recurrences of BCC. To test one such medicine, Weinstock chaired the six-site, six-year VA Topical Tretinoin Chemoprevential Trial, which last year found that the skin medication failed to prevent further instances of BCC in high-risk patients.
Weinstock is the corresponding author of the new study, published online July 19 in the Journal of Investigative Dermatology, which presents an analysis of the risk predictors of BCC recurrence found among the trial's population of 1,131 people, all of whom were veterans, 97 percent of whom were men, and whose median age was 72. On average, a participant had more than three episodes of BCC or squamous cell carcinoma before entering the study.
History, eczema, and early exposure
Overall, 44 percent of study participants developed new BCCs during the study period. The biggest predictor of another bout with BCC after three to four years of follow-up was a prior history of them. The 129 participants who had more than five BCCs in the five years before the study had a hazard rate ratio that was nearly four times as high as that of the 204 people who had none or one and more than twice as high that of the 200 people who had three.
Eczema was another predictor of BCC recurrence in the study's high-risk group. Participants who acknowledged a family history of the skin condition had a hazard rate ratio 1.54 times higher than people who did not, after statistical adjustments.
"We don't know why this is," Weinstock said. "The connection with eczema is something that's new, that needs to be further explored."
Age was another predictor, and not just in providing further confirmation that the risk people face increases with age. The study also showed that particularly intense sun exposure before the age of 30 was a strong a predictor of BCC occurrence among the high-risk study population, even though for most of them their 30s were decades ago.
"We talk about sun protection, which is important, but that's something for basal cell that's most important in your youth," Weinstock said. "While we don't exonerate UV exposure in one's 40s, 50s, and 60s, it was particularly UV exposure before the age of 30 that was most closely related to BCC in our study."
Awaiting a new trial
If limiting UV exposure is most crucial before the age of 30, what can doctors do for older people who may be headed for multiple bouts with BCC?
"Right now we have this wait and cut approach," he said. "We know these people are at high risk and we know that most of them are going to get more."
A better solution comes back to finding and testing preventive medication. Tretinoin didn't work, but Weinstock said he and his colleagues are testing another called 5-Fluorouracil. He said he is optimistic but has not yet seen the data from a trial that began about three years ago.