Clearance of a thick invasive squamous cell carcinoma after multiple treatments with topical photodynamic therapy.

OBJECTIVE

Tumor depth is the limiting factor for topical photodynamic therapy (PDT) treating cutaneous invasive squamous cell carcinoma (SCC). The thickness of  < 2-3 mm below the epidermis is the currently recommended effective response depth in nonmelanoma skin cancers. We report an unusual outgrowing SCC with a tumor depth of 5.5 mm, which was successfully treated with PDT.

METHODS

Topical 20% (wt/wt) 5-aminolaevulinic acid emulsion was applied for 6 h before irradiation with 633-nm red light. The lesion was irradiated 7 times, 1 week apart, at a total dose of 791 J/cm(2).

RESULTS

Twelve months later, histologic and clinical examination showed a complete remission and no local or systemic metastases. No serious side effects occurred, and the cosmetic outcome was excellent.

CONCLUSION

PDT may offer a noninvasive, well-tolerated, and effective therapy for inoperable low-risk SCC with an outgrowing pattern. It suggests that tumor depth is not an absolute predictor, but only a suggested reference.