Promise with narrow focus

September 1, 2007

All PDT treatments are not created equal and do not have equal therapeutic effects on basal cell carcinomas, according to the results of a recent german study. The new Chlorin-e6-Fotolon®-PDT method sets its mark and proves to be very effective in patients with multiple and deeper basal cell carcinoma lesions, possibly even more effective than ALA-PDT, according to one german expert.

Key Points

Berlin - According to the results of a recent German study, the treatment of basal cell carcinoma (BCC) with Chlorin-e6-photodynamic therapy (PDT) is effective and promising, but only for certain types of basal cell carcinomas.

Carsten M. Philipp, M.D., department of laser medicine at the Elisabeth Deaconess Hospital, Berlin, conducted a study with Chlorin-e6-PDT in nine patients with histologically proven basal cell carcinoma, including two patients with basal cell nevus syndrome (BCNS). Each patient had lesions ranging from a single BCC lesion to 30 lesions. Patients were followed up for 11 to 20 months.

Results showed no evidence of disease in six patients with BCC and in one patient with BCNS. One remission was recorded in each of the BCC and BCNS groups.

Each patient received Chlorin-e6, 2mg/kg BW (Fotolon, Apocare) intravenously, three to five hours prior to light exposure.

A diode laser (AOC) was used, 665nm (±10 nm), at maximum 40J/cm2 at 0.1W. The dose was given in one irradiation, while the surrounding tissues were covered.

"We found that BCCs treated with Chlorin-e6 and 665 nm light had an excellent response to the PDT. Compared with currently available topical photosensitizers for the treatment of BCC, Fotolon offers several significant advantages, such as secure photosensitization of deep portions of tumor, excitation with deep penetration wavelengths, a high cure rate even after a single treatment, high selectivity, easy fluorescence detection and a short time of elimination from skin compared with other systemic photosensitizers," Dr. Philipp tells Dermatology Times.

Dr. Philipp says intraoperative fluorescence detection with clinically common devices was used in all procedures, as the fluorescence assists in accurately delineating the diseased sites with the high contrast. The pain perceived by the patients was recorded as moderate, during and after the PDT treatment, and postoperative swelling occurred in all treated lesions, with significant swelling seen in treated lesions on the forehead. Of note, the photosensitivity of the skin of patients lasted less than 48 hours.

According to Dr. Philipp, treating superficial BCCs with 5-ALA is proven to be effective, and topical MAL (Metvix, Galderma) is approved for superficial and nodular types of BCCs in Europe. Though these treatments are effective, they are also associated with real concerns when treating larger nodular-type, morpheic- and multilocular BCCs, including the penetration of the ALA, accumulation of PpIX, a limited light penetration at 635 nm, and application problems and costs. Also, systemic PDT with HPD is effective with BCCs, but can lead to long-lasting skin sensitization.

"Treating multilocular and widespread BCC with systemic PDT using Chlorin-e6 Fotolon can also eliminate deep located and vascularized portions of tumors. This deeper penetration of light can be better achieved when combined with 665 nm light, as compared to 635 nm light," Dr. Philipp says.

Caveats and considerations

He says the Fotolon treatment does not and should not replace ALA, especially for a single or for superficial BCC lesions, as ALA clearly remains the treatment of choice.

However, in patients with multiple and/or deeper lesions that can involve bone and deeper structures, or in those where surgery is contraindicated, the Fotolon treatment has clearly proven its advantages in this study.

"I would not use this method for a single superficial BCC, as it would clearly overtreat the lesion. However, in all deeper lesions, such as large nodular or morpheic BCCs, I believe that ALA is not enough, and the new Fotolon method can produce better results," Dr. Philipp says.

Fotolon is not approved by the U.S. Food and Drug Administration.