SHORT COMMUNICATION 649
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Advances in dermatology and venereology Acta Dermato-Venereologica
Ambulatory Photodynamic Therapy for Superficial Basal Cell Carcinoma : An Effective Light Source ?
Janneke P . H . M . KESSELS 1 , 2 , Nedim DZINO 3 , Patty J . NELEMANS 4 , Klara MOSTERD 1 , 2 and Nicole W . J . KELLENERS-SMEETS 1 , 2 , 5
1
Department of Dermatology , Maastricht University Medical Centre , P . Debyelaan 25 , NL-6229 HX Maastricht , 2 GROW School for Developmental Biology and Oncology , Maastricht University , 3 Department of Ophthalmology , Erasmus Medical Centre , Rotterdam , 4 Department of Epidemiology , Maastricht University Medical Centre , Maastricht , and 5 Department of Dermatology , Catharina Hospital Eindhoven , The Netherlands . E-mail : janneke . kessels @ mumc . nl Accepted Jan 12 , 2017 ; Epub ahead of print Jan 17 , 2017
Photodynamic therapy ( PDT ) is a non-invasive treatment for several ( pre ) malignant superficial skin cancers , such as superficial basal cell carcinoma ( sBCC ), Bowen ’ s disease ( BD ) and actinic keratosis ( AK ) ( 1 , 2 ). PDT is traditionally known as an in-clinic treatment that can be time-consuming for both patients and healthcare personnel . Conventional PDT ( cPDT ) can be painful ( 3 ). In order to optimize comfort during treatment , new photosensitizing agents and light sources have been studied over the past decades .
Moseley et al . ( 4 ) reported on the use of a portable lowirradiance illumination source for sBCC . This ambulatory PDT ( aPDT ) device delivers a standard light dose at low irradiance ( 7 mW / cm 2 ) over a prolonged period of time , compared with other devices , such as the Aktilite ( 80 – 90 mW / cm 2 , Galderma SA , Lausanne , Switzerland ) ( 5 ). It is considered a patient-friendly , out-of-clinic treatment with lower pain scores compared with regular PDT ( 4 – 6 ).
This aim of this study was to evaluate retrospectively the risk of recurrence in patients treated with aPDT for primary sBCC , and the effect of tumour size on recurrence .
MATERIALS AND METHODS
Medical files of patients treated with aPDT between 1 February 2012 and 31 May 2013 in the Catharina Hospital , the Netherlands , were reviewed retrospectively . Inclusion criteria for this study were : patients with a histologically confirmed primary sBCC with a maximum diameter of 2 cm ( due to size limitation of the portable PDT device ). Exclusion criteria were : patients with genetic disorders causing skin cancer and those using immunosuppressive medication . The primary outcome measure was 1-year probability of remaining tumour-free . Treatment failure was defined as the presence of residual or recurrent tumour during follow-up visits . Follow-up visits were scheduled according to the local hospital protocol 3 and 12 months post-treatment . Secondary outcome measures were cumulative probability of recurrence-free survival at 6 and 18 months , and incidence of adverse events .
In case of slight hyperkeratosis , lesions were prepared by curettage using a wooden spatula to remove scales and crusts , to increase penetration of the active agent . Consecutively methylaminolaevulinic acid ( Metvix 16 %, Galderma SA , Penn Pharmaceutical Services , Gwent , UK ) was applied to the tumour itself and a 5-mm margin of surrounding normal tissue . A transparent occlusive bandage ( Tegaderm ® , 3M Healthcare , Minnesota , USA ), was applied , after which the portable PDT device ( Ambulight ® , Ambicare Health , Livingston , Scotland , UK ) was attached . The device remained switched off for 3 h . Subsequently , it switched on automatically and remained switched on for another 3 h , thereby delivering a total light dose of 75 J / cm 2 , with 7 mW / cm 2 irradiance .
The distribution of baseline characteristics was described by absolute numbers and percentages for categorical variables and mean ± standard deviation for age . Kaplan – Meier survival analyses were used to assess the cumulative probability of recurrence-free survival with 95 % confidence intervals ( CI ) at 6 , 12 and 18 months . Differences in recurrence-free survival between groups were tested for significance using the log-rank test . Follow-up ended at the date of a treatment failure or the date of the last follow-up visit . A 2-sided p-value ≤ 0.05 was considered to indicate statistical significance . Analyses were performed using SPSS version 23.0 and Stata version 14.0 .
RESULTS
During the study period 125 patients with 143 sBCC were treated with aPDT . The first diagnosed tumour per patient was included for analysis . In case a patient was treated for 2 or more primary sBCC on the same day , the largest tumour was chosen for analysis . A total of 104 patients had a histologically confirmed primary sBCC . Three patients were lost to follow-up directly post-treatment , because they preferred follow-up elsewhere . Thus , 101 patients remained for analysis . Baseline characteristics are shown in Table SI 1 .
Median follow-up time was 13 months ( range 2 – 23 months ) with 59.4 % of patients having completed a follow-up time of at least 12 months and 27 % more than 18 months . In 11 patients treatment failure was observed based on clinical observation , from which 9 occurred within 12 months . Eight of the clinically suspect recurrences were confirmed by histopathological examination , and 3 tumours were re-treated without histological confirmation . A total of 11 recurrences were included in the analysis .
At 3 months there were no patients with residual tumour . At 6 , 12 and 18 months the cumulative probability of recurrence-free survival was 93.6 % ( 95 % CI 86.3 – 97.1 %), 89.9 % ( 95 % CI 81.5 – 94.7 %) and 87.6 % ( 95 % CI 77.4 – 93.3 %). For 74 patients data on tumour size was available . These patients were categorized according to tumour size : ≤5 , 6 – 10 , and > 10 mm . The 1-year probability of recurrence-free survival was 100 % for the ≤ 5 mm size group and 92 % ( 95 % CI 78.5 – 97.6 %) and 72.9 % ( 95 % CI 42.6 – 89.0 %) for the 6 – 10 mm and > 10 mm groups , respectively , p = 0.014 ( Fig . S1 1 ).
Adverse events were reported in 2 patients : one reported blistering and erosions post-treatment , and the other had a bacterial skin infection , which was treated with topical antibacterial ointment .
1 https :// www . medicaljournals . se / acta / content / abstract / 10.2340 / 00015555-2610
This is an open access article under the CC BY-NC license . www . medicaljournals . se / acta Journal Compilation © 2017 Acta Dermato-Venereologica . doi : 10.2340 / 00015555-2610 Acta Derm Venereol 2017 ; 97 : 649 – 650