Nonsurgical innovations in the treatment of nonmelanoma skin cancer.

Abstract

Basal cell carcinoma and squamous cell carcinoma are the most frequent types of cancer in the United States and represent 75 percent and 20 percent, respectively, of all nonmelanoma skin cancers. Since ultraviolet radiation is implicated in their development, photoprotection is fundamental in their prevention. Additional preventive measures include identifying high-risk individuals for early detection along with using agents, such as retinoids, that are effective in decreasing the risk of premalignant cells further developing into carcinomas. Newer agents achieving this goal include perillyl alcohol, T4 endonuclease 5, DL-alpha-tocopherol, and alpha-difluoromethylornithine. Procedural modalities are currently the standard of treatment, but recent evidence has consistently shown that newer (nonsurgical) therapies, such as interferon, imiquimod, retinoids, and 5-fluorouracil, can be used effectively either as monotherapies or as adjuvants to those surgical modalities for the treatment of superficial nonmelanoma skin cancers and premalignant lesions. These newer therapies have achieved significant reductions in morbidity and mortality. Procedural modalities that have been evolving into important tools for the treatment of actinic keratosis and nonmelanoma skin cancers include photodynamic therapy and lasers. Nonsurgical therapies currently proving to be effective in clinical trials include ingenol mebutate and cyclooxygenase-2 inhibitors. Agents that are showing promising results in early phases of clinical trials include betulinic acid; hedgehog signaling pathway inhibitors, such as cyclopamine and GDC-0449; alpha-melanocyte-stimulating hormone analogs, such as afamelanotide; epidermal growth factor receptor inhibitors, such as gefitinib and erlotinib; anti-epidermal growth factor receptor monoclonal antibodies, such as cetuximab and panitumumab; and the 5-fluorouracil prodrug capecitabine.