An evidence-based, peer-reviewed journal for practicing clinicians in the field of dermatology
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24 JCAD JOURNAL OF CLINICAL AND AESTHETIC DERMATOLOGY February 2018 • Volume 11 • Number 2 R E V I E W Cryotherapy produced clearance in 10 lesions after one treatment, with the remaining 10 lesions requiring two or three additional treatments. PDT resulted in clearance of 15 lesions after one treatment and the remaining five lesions after a second treatment. The probability that a lesion cleared after one treatment was significantly greater with PDT (p<0.01). Cryotherapy was associated with ulceration (n=5), infection (n=2) and recurrent disease (n=20). No adverse events were associated with the use of PDT. Another controlled study assessed the relative efficacy of red and green light for the treatment of Bowen's disease. 27 Four hours following the application of 20% ALA, lesions were exposed to red 630±15nm (125J/cm 2 ) (n=32) or green 540±15nm (62.5J/cm 2 ) (n=29) light. The initial clearance rate for lesions treated by red light was 94 percent versus 72 percent (21 of 29) for green light (p=0.002). Over the following 12 months, there were two recurrences in the red light group and seven in the green light group, reducing the overall clearance rates to 88 percent and 48 percent, respectively. Based on these results, an open-label study assessed the efficacy of PDT using 630±15nm (100J/cm 2 ) to treat Bowen's disease consisting of 40 large lesions greater than 20mm in diameter and 45 multiple lesions. 28 ALA was used as the photosensitizer. Among the large lesions, 35 (88%) cleared after 1 to 3 treatments. Five lesions failed to clear but all showed partial response. Among the multiple lesions, 44 (98%) cleared following one or two treatments; however, four lesions cleared after 12 months, reducing the clearance rate to 89%. Basal cell carcinoma. Despite the success of PDT using ALA for Bowen's disease, superficial basal cell carcinoma of the skin (BCC) often respond poorly. The results of several studies report relapse rates of 50 percent or greater. 29–31 The objective of this open-label study was to determine whether a second PDT treatment after seven days could improve outcomes. One hour following the application of 20% ALA, six subjects with 26 BCC lesions were treated with 630±15nm red light (120–134J/cm 2 ; 50±100mW/cm 2 ). The treatment was repeated after seven days. A complete response rate of 100 percent was observed one month after treatment. During a median follow- up of 27 months (range, 15–45 months), relapse of one lesion occurred after 16 months. Cosmetic results were excellent. Actinic keratosis (AK). AK refers to rough, scaly lesions that can occur following long-term sun exposure in fair-skinned individuals. Consequently, they most often occur on the face, forearms, and back of the hands. 32 AKs are precancerous and might eventually progress to squamous cell carcinoma if left untreated. 21 PDT provides good cure rates and excellent cosmetic outcomes when used for the treatment of AK. 21,33 Our review found that when PDT was used with 20% ALA cream or solution, long-term cure rates were reported to be 78 to 89 percent using blue light and 85 to 89 percent using red light. 21 The following trial described the efficacy of PDT for the treatment of AK. Initially, human epidermal keratinocytes were incubated for 24 hours with ALA ranging from 100 to 500µmol/L and irradiated using 633nm light (3 to 24J/cm 2 ). 34 Cell viability was significantly reduced. Maximal cytotoxic effects were achieved using a light dose of 24J/cm 2 . Subsequently, a clinical ALA-PDT study was performed on 40 subjects with 294 AK lesions. 34 Subjects were included only if they showed a lesion distribution suitable for a two-sided comparison. Most lesions (81%) were located on the face or scalp, 15 percent were located on the hands, and four percent were located on the limbs. The treatment groups were very similar with respect to number of lesions and lesion grades. ALA 20% in a cream base was applied to each lesion and 5mm of surrounding normal tissue. After a four-hour incubation period, subjects were treated with 633nm light (40J/ cm 2 ). Immediately following treatment, subjects scored pain severity using an 11-point (0–10) scale. Subjects were evaluated after six, 12, and 24 weeks. The overall six- and 24-week complete response rates were 84.3 percent and 38.8 percent, respectively. 34 All treated lesions developed erythema and crusting 2 to 4 days after treatment, FIGURE 3. The effectiveness of phototherapy for the treatment demodex folliculitis is clearly evident in this patient before (left) and after 7 weekly treatment sessions with a red light=emitting diode (right). Images courtesy of the author. TABLE 3. Mean efficacy ratings RATING RETROSPECTIVE N (%) PROSPECTIVE UNTREATED N (%) PROSPECTIVE TREATED N (%) 3 MONTHS Very Good 17 (61) 18 (64) 19 (68) Good 7 (25) 6 (22) 7 (25) Fair 4 (14) 4 (14) 2 (7) 6 MONTHS Very Good 19 (68) 20 (72) 21 (75) Good 8 (29) 7 (25) 7 (25) Fair 1 (3) 1 (3) 0 (0) From Trelles et al 2006 14