Combination chemoprevention topical treatment reduces keratinocyte carcinoma incidence

Key takeaways:

• Patients’ odds of having cancer decreased after 1 year of treatment (OR = 0.06).
• The mean number of cryotherapy sessions decreased in the year after treatment compared with the year prior (1.5 vs. 2.3).

A combination of imiquimod 5% cream, 5-fluorouracil 2% solution and tretinoin 0.1% cream may be an effective chemoprevention option for reducing the incidences of keratinocyte carcinomas for at least 1 year, according to a study.

Although cure rates are high, incidences of keratinocyte carcinomas (KCs) are rising in the United States according to William J. Nahm, BA, an MD candidate at New York University Grossman School of Medicine in New York, and colleagues.

“Surgery remains the standard of care because of high cure rates; however, surgery can be associated with pain, bleeding, infection, scarring and prolonged recovery,” the authors wrote. “Chemoprevention is one method by which patients can reduce the incidence of malignant transformation to KCs.”

In this study, researchers evaluated the effectiveness a chemoprevention — a combination of imiquimod 5% cream, 5-fluorouracil 2% solution and tretinoin 0.1% cream (IMI/5-FU/TRET) — for KCs on the face, ears and scalp.

The retrospective review analyzed 327 patients who applied the combination evenly over the face, ears and non-hair-bearing areas of the scalp at a maximum frequency of five times a week for 6 weeks at their discretion.

Results showed that the patients’ odds of having KCs dramatically decreased after 1 year of treatment compared with the year prior to treatment in face, ear and scalp areas (OR = 0.06; 95% CI, 0.02-0.15) and other nontreated areas (OR = 0.25; 95% CI, 0.14-0.42).

The study also reported a lower mean number of cryotherapy sessions in the year after treatment compared with the year prior (1.5 vs. 2.3, respectively).

Notably, this study showed that IMI/5-FU/TRET may be more beneficial to nonsmokers than smokers. Results showed that while the recurrence of in-field cancer was low in both groups after 1 year of treatment, nonsmokers experienced a much lower rate (OR = 0.02; 95% CI, 0.003-0.15) compared with their smoking counterparts (OR = 0.16; 95% CI, 0.05-0.53).

The study reported that all patients experienced some sort of burning, erythema, scaling, pain and erosions during treatment. However, due to the self-regulatory nature of the application schedule, patients were able to adjust their dosage frequency based on their skin reactions while still maintaining effective outcomes.

“Although the present study is suggestive of combination therapy being effective for protection against KCs, prospective studies or randomized controlled trials will be necessary to better understand the effects of IMI/5-FU/TRET therapy,” the authors concluded.