Daylight photodynamic therapy for Bowen's disease☆☆☆

Bowen’s disease (BD) is considered an indolent neoplasm with high cure rates after non-surgical treatments, which are often the first-line therapy.1 The effectiveness of daylight photodynamic therapy (dPDT) in skin tumors has been demonstrated in studies with basal cell carcinomas.2 Moreover, two case reports of BD treatment with dPDT showed complete response in three BD lesions.3,4 To date, no prospective studies have attempted to assess dPDT efficacy in BD treatment. The aim of this clinical trial was to assess the efficacy of dPTD for BD lesions at Table 1 Demographic characteristics of patients.

limbs, five on the head/neck area, five on the trunk, and four on the upper limbs. The majority of the lesions received the dPDT sessions between 10 a.m. and 2 p.m. (n = 16; 66.7%), on sunny or partially cloudy days (n = 15; 62.5%). The mean temperature was 19.91 • C (± 5.2) at the first session and 17.54 • C (± 4.6) at the second session. The mean ultraviolet index (UVI) was 3.25 (± 2.8).
Lesions that presented a better response were located on the sun-exposed area, like the upper limbs and head/neck area (p = 0.01); however, no specific group of patients benefiting from the technique was observed ( Table 2).
The pain score perception during treatment was 0 in 79.2% of the treated lesions (n = 19), with a median visual pain score of 0 (range 0---3) in both sessions. The adverse effects most frequently reported by the patients were scaling and redness.
The findings of this study suggest that dPDT is a feasible alternative treatment for BD in selected cases. Complete response was found in six lesions after three months of follow-up, demonstrating that some cases would benefit from dPDT. Moreover, in 14 (58.3%) lesions improvement was observed in more than 75% of the lesion area, supporting its use as a neoadjuvant alternative. However, these findings for dPDT show that, when compared to cPDT, there were fewer complete response cases, demonstrating that the latter might still be generally preferable for BD patients. 1 Sample size and lack of a control group were limitations of the study, as well as the follow-up time. Future studies evaluating efficacy in a longer follow-up may corroborate the findings of this study. It is also assumed that re-treatment of lesions that have partially improved may increase the proportion of lesions with complete response over a long-term follow-up.

Financial support
Research and Events Incentive Fund of Hospital de Clínicas de Porto Alegre.

Authors' contributions
Carla Corrêa Martins: Statistical analysis; conception and planning of the study; drafting and editing of the manuscript; collection, analysis, and interpretation of data; participation in design of the study; intellectual participation in the propaedeutic and/or therapeutic conduct of the studied cases; critical review of the literature; critical review of the manuscript. Renato Marchiori Bakos: Approval of the final version of the manuscript; conception and planning of the study; drafting and editing of the manuscript; collection, analysis, and interpretation of data; participation in design of the study; intellectual participation in the propaedeutic and/or therapeutic conduct of the studied cases; critical review of the manuscript.
Manuela Martins Costa: Conception and planning of the study; drafting and editing of the manuscript; participation in design of the study.

Conflicts of interest
None declared.

Dear Editor,
Malignant melanoma (MM) is a skin tumor associated with a high mortality worldwide. The five-year survival rate is 95% if melanoma is detected early and only 5% for metastatic melanoma. 1 In Colombia, the national registry reported an increased incidence of melanoma from four to six cases per 100,000 people in merely four years. 2 This highlights the importance of identifying melanoma risk factors, especially in Latin-American countries were the distribution of histopathological subtypes of melanoma is divergent with the reports in other countries, where acral lentiginous melanoma (ALM) is the most frequent MM subtype. 3 Although a possible association with trauma has been reported, this association has not been clearly demonstrated. 4,5 Considering the aforementioned, a case-control study was performed between 2010 and 2014 in the population seen at the Federico Lleras Acosta Dermatology Center, a dermatological referral hospital in Bogotá, Colombia. Data from patients histologically diagnosed with melanoma were collected. The controls were those patients admitted to the same hospital for non-melanoma dermatological disease or non-melanoma skin cancer. All controls underwent a questionnaire and physical examination verifying that they had neither melanoma nor lesions clinically suggestive of melanoma. The cases and controls were age-matched by approximately five years. Two controls were assigned to each case Sociodemographic variables, history of working outdoors and outdoor sports participation throughout life, insecticide exposure, smoking, sunburn history, and a family history of skin cancer were studied. Individual phenotypic features including skin phototype, eye color, hair color, and signs of sun damage were also studied.
Associations through the chi-squared test, Student's t-test and Wilcoxon rank-sum were used for statistical analyses and a multivariate analysis using conditional logistic regression was performed, with statistically significant, This study included a total of 243 participants; 81 cases and 162 controls. The average subject age was 64 years. Analyzing the age by subtype, the patients with lentigo maligna averaged 67 years; the patients with acral lentiginous melanoma and nodular melanoma averaged 63 years; and those with superficial spreading melanoma averaged 58 years.
Nearly 73% (59/81) of the cases had completed secondary school, compared with 71% (115/162) of the controls, which was not a significant difference (p = 0.7 by chi-squared test). Table 2 shows the results of the bivariate analysis which reveals that having worked outdoors during early adult life (15---30 years old) increased the risk of developing melanoma by 1.9 times. The most frequent occupations among cases and controls in this period were farming activities (54% vs. 67%), construction (5% vs. 4%), and outdoor sales (11% vs.