A drug previously used for treatment of skin growths has been found to help prevent the development of certain skin cancers, according to a new clinical trial in the Journal of the American Medical Association. Led by Martin Weinstock, professor of dermatology and epidemiology at the Alpert Medical School, the trial examined patients from Veterans Affairs hospitals around the country and found that a course of fluorouracil 5 percent (5-FU) cream substantially reduced the risk of developing one type of skin cancer — making 5-FU the first drug known to continue to prevent squamous cell carcinoma after the duration of its course.
“Here, for the 5-FU, it’s one course for two to four weeks, and then a year’s worth of risk reduction,” Weinstock said.
According to Weinstock, 5-FU has been used for decades in order to treat a specific kind of growths. While not cancerous, these sun-induced skin growths can evolve into cancerous squamous cell carcinomas if not treated.
Being a chemotherapy medication, 5-FU likely works by inhibiting cancer cells from growing on the skin, said Christopher Dimarco, assistant professor of dermatology at the Med School, in a statement to The Herald.
“It was natural to see whether this medication could be effective in preventing skin cancers,” Weinstock said, adding that research into skin cancers has been a career goal of his.
The patients involved in the trial were considered “high-risk” since they were veterans who had two or more of the cancers in question on the face or ears prior to beginning the course, said Julia Siegel, a resident who worked as a Dermatoepidemiology Research Fellow during the study. Of those studied — 932 patients from 12 VA medical centers across the country — the majority were elderly Caucasian men, a group that tends to develop skin cancers at high rates, Siegel said.
The trial focused on two forms of skin cancer, namely basal cell and squamous cell carcinomas. Researchers were hopeful that the drug would help prevent both, Weinstock said. But while the results showed a marked 75 percent reduction in risk for squamous cell carcinoma, the reduction for basal cell carcinoma was not significant.
This distinction is not surprising because, while certain growths commonly treated with 5-FU have been shown to be precursors to squamous cell carcinoma, less is known about their relationship with basal cell carcinoma, Siegel said.
Basal cell carcinoma and squamous cell carcinoma are the first- and second-most prevalent forms of skin cancer respectively, Dimarco said. They are estimated to account for 75 percent of all cancers diagnosed in the United States, he added, but this statistic isn’t tracked by national databases and comes from insurance data.
Both Weinstock and Siegel emphasized the trial’s importance to future treatments. “It’s such an exciting finding because it could save people from these surgeries and from the stress and worry that comes from having these skin cancers,” Siegel said.
“It means we have a good starting point and another option now, but we still have a ways to go to prevent squamous cell and basal cell carcinoma,” Dimarco said. “We need to study it more to optimize the treatment.”
According to Weinstock, the number of reported cases of these cancers has dramatically increased during recent years, and now reaches upwards of five million in the United States. “One of my goals has been to turn that around,” Weinstock said.
Weinstock, Siegel and Dimarco all noted the importance of sunscreen use in preventing skin cancers. Dimarco pointed to a study which found that sunscreen use reduced the risk of developing squamous cell carcinoma by up to 40 percent.
