Rhenium-188 resin therapy for non-melanoma skin cancer.

Non-melanoma skin cancer (NMSC), which includes basal cell carcinoma and cutaneous squamous cell carcinoma, is the most common malignant neoplasm worldwide, with an increasing incidence in Europe and Spain. Although surgery remains the treatment of choice, there are patients in whom this option is not feasible or does not ensure a satisfactory functional and esthetic outcome. Rhenium-188 (Re-188) resin represents a minimally invasive, painless, and outpatient therapeutic alternative, allowing the delivery of high doses of localized beta radiation to lesions up to 3 mm in depth while preserving healthy surrounding tissue. Its physical and radiobiological principles are based on the emission of beta particles with limited penetration and on both direct effects on tumor DNA and indirect effects mediated by reactive oxygen species and the bystander effect. Published clinical series report complete response rates above 90-95%, with low recurrence and an acceptable safety profile, predominantly grade 1-2 toxicity. Esthetic results are generally good to excellent, with high patient satisfaction. Moreover, promising outcomes have been described in non-approved indications such as extramammary Paget's disease and keloid scars. In conclusion, Re-188 resin therapy constitutes an effective and safe option for selected patients with NMSC, particularly those who are not candidates for surgery or have lesions in anatomically complex locations. Its progressive implementation in specialized centers will help standardize protocols and expand the available clinical evidence.