Why carry out this study?

Keratinocyte tumors are the most frequent human tumors found in medical pracice. A surgical approach is not always the best option, and radiotherapy, as well as systemic chemotherapy, comes with a high burden of costs and side effects.

Intralesional chemotherapy, in particular with MTX, could be a conservative yet effective treatment option.

What was learned from the study?

Keratoacanthoma (KA) response rate to intralesional MTX is excellent. All KAs in our study improved partially or completely. About one half of squamous cell carcinomas showed either improvement or resolution, while basal cell carcinoma had no improvement.

A treatment protocol consisting of weekly injections, performed for 4–6 weeks, seemed to be the most efficient. Dosages ≤ 20 mg/ml per session showed little efficacy compared with 25 mg/ml doses. The latter appeared more effective than 50 mg/ml as well.

For selected cases, intralesional MTX can be a safe and effective option for the treatment of KT, especially in case of keratoacanthomas and, to a lesser extent, SCC.