Topical 5-fluorouracil, calcipotriene efficacious for superficial keratinocyte carcinomas

Key takeaways:

• Researchers saw a response rate of 91% across groups.
• Among immunosuppressed patients, 89% also achieved a complete response.

ORLANDO — Topical 5-fluorouracil and calcipotriene proved to be highly effective for superficial keratinocyte carcinomas, according to a presentation at the American Society for Dermatologic Surgery Annual Meeting.

“There are various approaches to treating superficial keratinocyte carcinomas,” Emily Stamell Ruiz, MD, MPH, associate professor of dermatology at Harvard Medical School and director of the high-risk skin cancer clinic at Dana-Farber Cancer Institute, told Healio.

“Topical regimens have been shown to be efficacious, but the length of treatment can be challenging for patient compliance. The combination of 5-fluorouracil and calcipotriene is a shorter regimen but there are limited data in superficial keratinocyte carcinomas (KCs),” Ruiz, who is also program director of the micrographic surgery and dermatologic oncology fellowship and academic director of the micrographic surgery center at Brigham and Women’s Hospital, continued.

To elucidate the effects of combination 5-fluorouracil and calcipotriene on KCs, Ruiz and colleagues conducted a retrospective chart review of 163 patients with 209 superficial KCs.

Of these 209 tumors, 179 were squamous cell carcinoma in situ (SCCIS) and 30 were superficial basal cell carcinoma (sBCC). Twenty percent of the patients were immunosuppressed, 57% were men and the mean age of the cohort was 72 years.

Ten percent of the SCCIS tumors had adnexal extension, a characteristic that Ruiz states did not impact the endpoints.

After a follow-up time of 15 months, results showed that 92% of patients were compliant with the treatment regimen, the average length of time being 8.3 days at two times per day. Also, 6.7% of patients encountered complications, the majority of which were “an exuberant reaction to the topical regimen,” according to Ruiz.

The researchers saw a response rate of 91%. The response rates among the subgroups were 92% for SCCIS and 83% for sBCC, a difference which was not considered statistically significant. Eighty-nine percent of immunosuppressed patients also achieved a complete response.

Seven of the tumors locally recurred after 21 months, none of which were among the immunosuppressed cohort. Three of the tumors were retreated with the combination topical or underwent other nonsurgical modalities except for two tumors which were excised during Mohs surgery due to being nodular BCCs.

Nine percent of tumors did not achieve a complete response after the initial round of treatment, including 8% of the SCCIS cohort and 5% of the BCC cohort. Also, 37% of these tumors were found to be dermally invasive. The remainder were either retreated topically or with other nonsurgical modalities (21%) or underwent Mohs surgery (26%).

Overall, the 2-year recurrence-free survival rate was 95% (95% CI, 86%-98%) among the SCCIS cohort and 84% (95% CI, 47%-96%) among the sBCC cohort.

“Topical 5-fluorouracil and calcipotriene is highly effective for superficial keratinocyte carcinomas,” Ruiz concluded. “We saw similar efficacy for immunosuppressed patients as well as those tumors with adnexal extension. This regimen should be considered for superficial keratinocyte carcinomas and in particular for patients with diffuse actinic damage/field cancerization.”