Healing light: PDT used to treat multiple BCCs on burn scars

August 1, 2009

Several noninvasive therapeutic approaches can be used to treat superficial basal cell carcinoma.

Key Points

In a recent case study, PDT was successfully used in the treatment of multiple superficial BCCs arising in the scars of a burn patient.

Lorea Bagazgoitia, M.D., department of dermatology, Hospital Ramón y Cajal, Madrid, Spain, saw a 55-year-old male patient with a childhood history of thermal burn trauma on the back and right thigh, leaving burn scars of 25 cm by 30 cm and 7 cm by 10 cm, both areas healing by secondary intention.

The multiple lesions of the patient were treated with two cycles of MAL (methyl aminolevulinate) and red light, with sessions spaced one week apart, for a total of six treatments.

Results showed that the MAL-PDT treatments could achieve a complete clearance of all lesions on the back and right thigh of the patient. Total clearance results could be confirmed through histology and fluorescent diagnosis.

In this patient, most of the superficial BCC lesions resolved after the first treatment with MAL-PDT. Some of the lesions were thicker, with nodular components, and these required more than a single treatment.

According to Dr. Bagazgoitia, PDT is a very effective therapy for the treatment of superficial as well as nodular BCCs on scars. The nodular component of a nodular BCC can be curetted and then followed by the PDT therapy.

Therapies

In MAL and ALA-PDT therapy, Dr. Bagazgoitia says that both substances get absorbed by the epithelial cells and work by selectively interfering with the heme synthesis, specifically with the production of protoporphyrin 9 (PP9), in those cells that have a higher proliferative rate; in this case, the malignant basal cells.

These cells that contain a higher amount of PP9 become more sensitive to light, and when red light is applied to the skin surface, a photodynamic reaction takes place, producing oxygen reactive species, which induces apoptosis and necrosis in the targeted cells, leaving the healthy cells unaffected.

Other therapeutic modalities for the treatment of superficial BCCs include topical diclofenac, 5-fluorouracil and imiquimod, as well as desiccation and curettage. Dr. Bagazgoitia often prefers to use MAL-PDT or imiquimod for superficial BCCs. Both approaches can also be used in nodular BCCs, Bowen's disease and actinic keratosis.

The pathogenic mechanism of the development of superficial BCC on burn scars remains unknown; however, mutations of p53 have been reported in tumors found on burn scars.

Disclosure: Dr. Bagazgoitia reports no relevant financial interests.