Photodynamic Therapy and Vismodegib for Multiple Basal Cell Carcinomas

Use of PDT for the treatment of BCC Indications for PDT include superficial and nodular BCC. Eight randomized clinical trials have reported the results of PDT for superficial or nodular BCC with a total of 1583 patients. Results of the meta analysis showed overall complete clearance of PDT was 86.4 % compared to 98.2 % for surgery. The 1 year recurrence for PDT was 10.3 % vs 0. 6% for surgery. Cosmetic outcomes were much better with PDT than surgery. (Wang, 2015). A randomized controlled trial of PDT with MAL versus surgical excision in 196 patients with superficial BCC showed a 9.3% recurrence rate for PDT versus a 0% recurrence rate for surgery at 12 months. However, the good-to-excellent cosmetic outcome was 94% and 60% for patients treated with PDT and surgical excision, respectively. Similarly, in trials of PDT versus surgery for nodular BCC, recurrence rates are less than 5% for surgery versus 14% to 30% for PDT with ALA. As with superficial BCC, cosmetic effects are consistently shown to be more favorable with PDT with ALA (Wang, 2015). In the largest single institution experience with 1440 nodular and superficial BCCs, PDT using systemically administered porfimer sodium showed an initial (6-month) complete response rate of 92%, with a recurrence rate of less than 10% at 4 years. At this same institution, a 92% complete response rate was achieved with PDT with topical ALA in 330 patients with superficial BCC, but the response rate dropped to 71% in 75 patients with nodular BCC. In a multicenter randomized trial of PDT with MAL versus cryotherapy for superficial BCC, complete response rates at 3 months were 97% and 95%, respectively, with 5-year recurrence rates of 22% and 20% for PDT with MAL and cryotherapy, respectively. In this study, the excellent-to-good cosmetic outcome was 89% for PDT with MAL and 50% for cryotherapy. Several clinical studies have reported an increase in the initial response rate with a lower recurrence rate after repeated PDT sessions. Initial responses usually are apparent between 3-6 months after treatment when the skin has healed over and treatment related changes have resolved. Cycles of MAL PDT repeated after 3 months for persistent BCC has been shown to offer high and durable response rates. Both efficacy and safety have also been demonstrated using repeated sessions with red or blue light at follow up times of 3, 6 and 12 months. At Roswell Park Cancer Institute, Oseroff and colleagues safely used repeated sessions of ALA PDT in children with BCNS (multiple BCC), and Gilchrest also reported the benefits of ALA PDT with red light at 2-4 month interval treatments. The most common adverse event with either ALA or MAL PDT is the burning or stinging pain experienced by patients during illumination. Zeitouni and colleagues published their retrospective and prospective data using a 2 step irradiance approach with ALA/MAL PDT and red light in non BCNS patients with multiple BCC. Follow up times ranged from 6-24 months. The 2 step irradiance schedule (bilevel) effectively minimized the treatment related pain and maintained good clinical outcomes (Zeitouni x 2).