# Chemoprevention in Skin Cancer: What Advice?

## TL;DR

This review discusses chemopreventive agents for skin cancer, focusing on their effectiveness, safety, and challenges in clinical trials.

## Contribution

The paper provides an updated review of chemopreventive therapies for skin cancer, highlighting their efficacy and limitations in different patient groups.

## Key findings

- Acitretin, nicotinamide, 5-fluorouracil, and photodynamic therapy show promise in treating actinic keratosis and squamous cell carcinoma.
- Clinical trials face challenges like sample size and long follow-up periods, limiting the assessment of chemopreventive agents.
- More research is needed for chemoprevention in melanoma and other aggressive skin cancers due to their higher mortality rates.

## Abstract

Chemopreventive agents in cutaneous oncology target the prevention of skin cancer and the active treatment of precancerous lesions. The ideal chemopreventive agent should be both safe and effective, have minimal interactions, and, to improve patient compliance, be easy to use and inexpensive. Although several drugs have been studied, the main obstacles for the assessment of their efficacy are difficulties in the design and conduction of clinical trials, including sample sizes and long follow-ups. To date, acitretin, nicotinamide, 5-fluorouracil, and photodynamic therapy have shown promising results and are currently used in clinical practice.

The incidence of melanoma and non-melanoma skin cancers (NMSCs) is increasing worldwide. While NMSCs are more common, melanoma remains the most challenging because of its higher aggressiveness. Although the use of sunscreens is key in high-risk populations, it provides limited protection, which highlights the need for alternative solutions. In this review, we discuss current evidence on chemopreventive therapies, as well as their efficacy and adverse events, including immunocompetent and immunosuppressed patients. Acitretin, nicotinamide, 5-fluorouracil, and photodynamic therapy have shown overall promising results in actinic keratosis and squamous cell carcinoma. Nevertheless, more research is needed to establish their efficacy, particularly in melanoma, Merkel cell carcinoma, and cutaneous lymphoma, due to their higher mortality rates.