Using 5-FU to treat actinic keratosis can minimize risk of squamous cell carcinoma requiring surgery

Using the generic skin cream fluorouracil 5% (5-FU) for two to four weeks may reduce the risk of a squamous cell carcinoma (SCC) needing surgery by 75%. A single course of 5-FU reduced surgery for SCC for up to one year. The results come from a study published online in the journal JAMA Dermatology (Jan. 3, 2018) which involved military veterans at high risk for keratinocyte carcinoma. A total of 932 veterans participated in the clinical trial, which was funded by the U.S. Department of Veterans Affairs.

“The most remarkable thing about this study is that now we have something to use that doesn’t lose its effectiveness when you stop using it,” said lead author Dr. Martin A. Weinstock, professor of Dermatology and Epidemiology at Brown University and chief of Dermatology at the Providence Veterans Affairs Medical Center, in a press release. “But this is the first study of its type. I’m hopeful there will be other studies that show other sorts of regimens that last longer and do a better job over time as science progresses. This is an important first step.”

Squamous cell carcinoma. Photo by The British Skin Foundation.

Between 2009 and 2013 participants who each had at least two prior BCCs or SCCs received the 5-FU cream, or a similar cream without the active ingredient as an experimental control. For up to four weeks, the veterans were instructed to apply their cream twice a day on their face and ears. They also received a 30 SPF sunscreen and were briefed about skin cancer, sunscreen and sun safety.

The two experimental groups were almost exclusively Caucasian and male, averaged 71 years of age and reported similar degrees of prior sun exposure and sunburn.

The double-blind trial required both groups to visit their Veterans Affairs centre twice a year for two to four years for follow-up exams with a dermatologist.

After the first year, 20 of the 464 veterans in the control group developed an SCC that required surgery, but only five of the 468 veterans who received 5-FU did.

For the subsequent three years, there was no longer a significant difference between the two groups in the number of patients who required surgical treatment for an SCC.

For BCCs, there was an 11% reduced risk after the first year among the group that received 5-FU, but that difference was not statistically significant. In the second year, BCC cases requiring surgery increased in the 5-FU group, but in years three and four, and when the study ended, there was no significant overall difference in risk of developing a BCC requiring surgical treatment.

After four years, 298 of the participants had developed at least one BCC, and 108 had developed at least one SCC.

 The trial also resulted in a significant decrease in the need for Mohs surgery to treat a BCC in the first year. According to Dr. Weinstock, Mohs surgery is more effective but also more elaborate and expensive than conventional procedures. In the study’s first year, 36 BCCs were treated with Mohs surgery in 27 participants in the control group, but only 17 BCCs were treated with the procedure among 14 patients in the 5-FU group.

“This suggests that using the 5-FU can reduce the resources needed to treat these carcinomas,” said Dr. Weinstock.

In his clinical work Dr. Weinstock has recommended 5-FU treatment for particularly high-risk patients. Based on the study results, patients may need to renew their regimen with the cream every year.

With his colleagues, Dr. Weinstock is planning further studies, including one to determine the cost-effectiveness of 5-FU treatment.

Dr. Martin A. Weinstock. 

Photo by Brown Dermatology. 

With his colleagues, Dr. Weinstock is planning further studies, including one to determine the cost-effectiveness of 5-FU treatment.