Indications and limits of postoperative radiotherapy for skin malignancies

To provide a summary of the current evidence, with a focus on recent publications, pertaining to indications for postoperative radiation therapy for cutaneous squamous-cell carcinoma (cSCC), basal-cell carcinoma, Merkel-cell carcinoma and melanoma of the head and neck.

Meta-analyses in cSCC and Merkel-cell carcinoma have shown an association between postoperative radiation therapy and overall survival. Prospective phase III data in head and neck cSCC has shown excellent locoregional control following surgery and postoperative radiation therapy. The addition of concurrent cytotoxic chemotherapy to postoperative radiation therapy has not improved outcomes in either of these two entities. Postoperative immune checkpoint inhibition or combined BRAF and MEK blockade in stage-III melanoma improves progression-free survival whereas postoperative radiation therapy does not.

Further improvement in outcomes with high-risk cSCC and Merkel-cell carcinoma might be achieved with concurrent or sequential immune checkpoint inhibition and postoperative radiation therapy. Postoperative radiation therapy for cutaneous melanoma should be reserved for patients in whom novel systemic therapies are not a treatment option.