125 the Epidemiology and Clinical Characteristics of Extramammary Paget Disease Patients in Canada and Assessing the Risk of Second Malignancies

Extramammary Paget Disease (EMPD) is a rare intraepithelial adenocarcinoma that arises in apocrine gland bearing skin and presents as a chronic rash that resembles several disorders such as eczema, cutaneous T cell lymphoma, Langerhans cells histiocytosis, intraepithelial neoplasia, fungal infections and psoriasis. EMPD is often associated with underlying or distant malignancies. The epidemiology of EMPD in Canada is poorly understood. Further, the risk of developing second malignancies in Canadian EMPD patients was not evaluated prior to the presented study. In this study, we analyzed clinical characteristics, incidence and geographical distribution of EMPD patients in Canada from 1992 to 2015 using the Canadian Cancer Registry (CCR) and the topography and morphology are coded according to the International Classification of Diseases for Oncology (ICD-O). In summary, in Canada, 845 patients were diagnosed with EMPD between 1992 and 2015. The mean incidence rate of EMPD in Canada was 1.1 cases per 1 million individuals per year with noteworthy variations in the incidence across the country. The male:female incidence ratio of EMPD was 1.00:1.87. The incidence of EMPD in Canada increased steadily within the aforementioned period. Analysis of the occurrence of second malignancies in EMPD patients revealed that 29.6% of EMPD patients developed at least one additional malignancy, with the majority being adenocarcinoma at gastrointestinal sites. The mean time between EMPD and the cancer before and after EMPD was 6.41 and 6.58 years, respectively. In conclusion, our study confirms increased risks of underlying malignancies in EMPD patients. Epidemiological studies, such as the presented one here, shed light on the risk factors associated with the development of EMPD and encourage regular screening of EMPD patients for second and/or underlying malignancies.