Effectiveness of photodynamic therapy for mammary and extra-mammary Paget's disease: a state of the science review

Following Cochrane guidelines, a comprehensive systematic review of all clinical studies and reports examining the use of PDT for mammary and extra-mammary Paget's disease was conducted. Study quality was assessed using the Oxford Levels of Evidence Scale.21 retrospective and 2 prospective non-comparative studies were identified and included in the review: 9 case reports with 1-2 patients and 14 case series with 1-16 patients. These reports totalled 99 patients with 133 extra-mammary Paget's lesions and 3 patients (with 3 lesions) with mammary Paget's disease. Follow-up periods were typically one year or less, with 77/133 extra-mammary lesions exhibiting complete response to PDT. One recurrent mammary skin lesion and two mammary lesions treated concomitantly with surgery also exhibited complete responses.Evidence of the effectiveness of PDT for Paget's disease is promising, but limited. This may, in part, be explained by the rarity of the condition, making controlled comparative clinical trials challenging.Paget's disease is an extremely rare form of intraepithelial adenocarcinoma that may have an underlying tumour component. It primarily affects Caucasian women over the age of 50[1]. Since in its early stages symptoms are often minor, individuals may not seek medical attention for several years, delaying diagnosis and treatment[1-3]. In addition, the condition can be misdiagnosed as eczema or dermatitis,[4] with a benign dermatologic diagnosis creating further delays[5].Paget's disease is categorized as either mammary or extra-mammary. While the two types are histologically the same (the epidermis shows diffuse infiltration of large vacuolated cells with a bluish cytoplasm (Paget cells)), the location differs[6]. Mammary Paget's disease involves the skin of the breast, in or around the nipple. Most individuals with the condition (> 92%) have underlying breast cancer (either ductal carcinoma in situ or invasive breast cancer)[2,7]. Extra-mammary Paget's disease main