Topical treatment of basal cell carcinoma with tazarotene: a clinicopathological study on a large series of cases.

BACKGROUND: Basal cell carcinoma (BCC) is the most common cancer in humans. Medical treatment modalities offer cost reductions and clinical advantages in selected cases such as low-risk areas, surgically inaccessible sites, patients with multiple neoplasms, and older, infirm or anticoagulated subjects. Tazarotene has been proposed for the treatment of BCC; however, data on its efficacy are lacking. OBJECTIVES: To investigate the efficacy of tazarotene in a large series of BCCs, better to define the clinical advantages and the mechanisms of action in vivo. METHODS: Tazarotene 0.1% gel was applied daily for 24 weeks to 154 small superficial and nodular BBCs. Clinicopathological changes were followed during the therapy by dermoscopic and histological examination. Proliferation, retinoic acid receptors and apoptosis were investigated by immunohistochemistry and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick-end labelling on biopsies. RESULTS: At 24 weeks of therapy, 70.8% of the BCCs showed > 50% clinical and dermoscopic regression, and 30.5% healed without recurrences after 3 years of follow-up. At 12 weeks, biopsies showed that regression was associated with reduced proliferation and increased apoptosis of basaliomatous cells. Most unresponsive tumours displayed a keratotic differentiation. CONCLUSIONS: Tazarotene was effective in the majority of superficial and nodular undifferentiated BCCs treated, possibly by antiproliferative and proapoptotic actions in vivo. Keratotic BCCs were the major type among the unresponsive tumours, and were characterized by overexpression of p53 and cellular retinol binding protein-1 in comparison with undifferentiated tumours. Topical tazarotene represents an alternative medical choice for selected cases of BCC.