Huidkanker en PDT - Photodynamische Therapie met Methyl Aminolevulinate meest effectief en geeft cosmetisch beste resultaat bij vormen van huidkanker in vergelijking met cryosurgery met een spray en/of zalf met 5-FU erin. Artikel geplaatst 30 juni 2006

30 juni 2006: Bron Medscape

PDT met gebruikmaking van Methyl Aminolevulinate is het meest effectief en geeft cosmetisch het beste resultaat in de verwijdering van huidtumoren met het plaveiselcarcinoom type. Het verschil blijkt significant in het voordeel van PDT met Methyl Aminolevulinate. Dit blijkt uit een gerandomiseerde studie waarbij Methyl Aminolevulinate werd vergeleken met cryosurgery door middel van een spray en een zalf met 5-FU erin en een placebozalf. Hier een beschrijving van de studie zoals Medscape die gisteren liet uitgaan.

Photodynamic Therapy With Methyl Aminolevulinate Effective for Squamous Cell Carcinoma CME News Author: Laurie Barclay, MD CME Author: Charles Vega, MD, FAAFP June 26, 2006 — Photodynamic therapy (PDT) with topical methyl aminolevulinate is effective for squamous cell carcinoma in situ and offers excellent cosmesis, according to the results of a multicenter, randomized trial reported in the June issue of Archives of Dermatology. "PDT is a noninvasive and precisely directed treatment that offers promise in this indication," write Colin Morton, MD, from the Stirling Royal Infirmary in Scotland, and colleagues. "The procedure involves activation of a photosensitizing agent by visible light, with subsequent release of reactive oxygen species, especially singlet oxygen, which in turn produces local tissue destruction." At 40 outpatient dermatology centers in 11 European countries, a random sample of 225 patients with histologically confirmed squamous cell carcinoma in situ (lesion size, 6 - 40 mm), and no evidence of progression was randomized to treatment with PDT with methyl aminolevulinate (160 mg/g; n = 96) or matching placebo cream (n = 17), cryotherapy with liquid nitrogen spray (n = 82), or topical fluorouracil applied for 4 weeks (5% cream; n = 30). Methyl aminolevulinate or placebo cream was applied for 3 hours before illumination with broadband red light (75 J/cm2, 570 - 670 nm), and treatment was repeated 1 week later. Lesions with a partial response at 3 months were retreated, and follow-up took place at 3 and 12 months after the last treatment. The primary endpoints were clinically verified complete response of lesions, and blinded and on-site assessment of cosmetic outcome on a 4-point rating scale. At 12 months, the estimated sustained lesion complete response rate was 80% with methyl aminolevulinate PDT; 67% with cryotherapy (odds ratio, 1.77; 95% confidence interval [CI], 1.01 - 3.12; P = .047); and 69% with fluorouracil (odds ratio, 1.64; 95% CI, 0.78 - 3.45; P = .19). Cosmetic outcome at 3 months was good or excellent in 94% of patients treated with methyl aminolevulinate PDT, in 66% of patients treated with cryotherapy, and in 76% of patients treated with fluorouracil. Good cosmesis was maintained at 12-month follow-up. "Methyl aminolevulinate PDT is an effective treatment option for squamous cell carcinoma in situ, with excellent cosmesis," the authors write. "Although follow-up to 24 months is still continuing, the high clearance rate with methyl aminolevulinate PDT at 3 months, which was sustained at 12 months, together with favorable cosmetic outcome and safety profile, indicates that methyl aminolevulinate PDT is a promising treatment alternative that warrants consideration in the clinical management of SCC [squamous cell cancer] in situ." PhotoCure ASA supported this study. Dr. Morton has disclosed receiving financial support from Galderma, PhotoCure ASA, Phototherapeutics UK, and Schering AG for performing clinical trials. Arch Dermatol. 2006;142:729-735 Learning Objectives for This Educational Activity Upon completion of this activity, participants will be able to: Describe the epidemiology and treatment of squamous cell cancer in situ. Compare the efficacy and cosmetic results of PDT vs cryotherapy and fluorouracil treatment of squamous cell cancer in situ. Clinical Context Nonmelanoma skin cancer is the most common cancer among whites, and squamous cell carcinoma in situ is found most frequently among older adults. The lower leg is the most common area affected by squamous cell carcinoma, although these lesions have a risk for progression of only approximately 3%. Cryotherapy, curettage, excision, and topical fluorouracil are all generally similar in their efficacy in treatment of squamous cell carcinoma in situ. PDT uses visible light to activate a photosensitizing agent, which in turn releases reactive oxygen species that lead to focal tissue destruction. The current study compares PDT with cryotherapy and fluorouracil in the treatment of squamous cell carcinoma in situ. Study Highlights Patients eligible for study participation were adults with pathology-confirmed squamous cell carcinoma in situ. Patients with lesions treated within the 3 months prior to study entry or whose squamous cell carcinoma was strongly pigmented, less than 6 mm in diameter, or more than 40 mm in diameter were excluded from the research protocol. Participants were randomized to receive treatment consisting of PDT with topical methyl aminolevulinate cream, PDT with matching placebo cream, or standard therapy of cryosurgery or fluorouracil. Methyl aminolevulinate, 160 mg/g, or placebo cream was applied to the squamous cell carcinoma for 3 hours, at which time it was washed off with saline. The application area was then illuminated with noncoherent red light. This treatment was repeated after 1 week. Cryosurgery was performed with a single freeze-thaw cycle, with the freeze period lasting 20 seconds. Topical 5% fluorouracil cream was applied daily for 1 week and then twice daily for another 4 weeks. The main study outcomes were response to treatment and posttreatment cosmesis. Response was judged to be complete (100% disappearance of lesion), partial (lesion size decreased by between 25% and 99%), and none (less than 25% disappearance of lesion) at 3 and 12 months. The assessment of cosmesis was performed by the study investigator as well as by means of photographs evaluated by a clinician blinded to subjects' randomization group. Efficacy analyses were performed on a per-protocol basis. 96 participants comprised the methyl aminolevulinate PDT group, while the placebo PDT, cryotherapy, and fluorouracil group included 17, 82, and 30 individuals, respectively. Patient and lesion characteristics were similar between treatment groups. The mean age of subjects was 72 years old, and the mean diameter of the largest lesion was 19 mm. Most squamous cell carcinomas were located on the extremities. Treatment was completed in 1 cycle in 84%, 71%, and 72% of the methyl aminolevulinate PDT, cryotherapy, and fluorouracil groups, respectively. The complete response rates were 93%, 21%, 86%, and 83% in the methyl aminolevulinate PDT, placebo PDT, cryotherapy, and fluorouracil groups at 3 months, respectively. At 12 months, the complete response rates were 80%, 67%, and 69% in the methyl aminolevulinate PDT, cryotherapy, and fluorouracil groups, respectively. Overall, methyl aminolevulinate increased the rate of complete response at 12 months by 73% vs standard therapy. Statistically, methyl aminolevulinate was superior only to cryotherapy, not fluorouracil, in this outcome. Larger lesions were less likely to have a complete response, regardless of study treatment. Good or excellent cosmetic outcomes were achieved in 94%, 66%, and 76% of subjects in the methyl aminolevulinate PDT, cryotherapy, and fluorouracil groups, respectively, and this superior result for active PDT treatment vs both standard therapies was also borne out at 12 months. Local adverse reactions were common with all active study treatments. Severe local reactions were experienced by 6% of patients receiving methyl aminolevulinate PDT and 12% of subjects receiving cryotherapy. Pearls for Practice Squamous cell carcinoma is most common in older adults, and it most commonly grows on the lower legs. Several available treatments have similar efficacy in the management of squamous cell carcinoma in situ, and the risk for progression is approximately 3%. In the current study, methyl aminolevulinate PDT was statistically superior to cryotherapy and similar to fluorouracil in the response of squamous cell carcinoma in situ to treatment. Methyl aminolevulinate PDT also produced the best cosmetic results following treatment.