P14 Epidemiological and clinical characterization of patients with multiple primary melanomas in a Greek cohort

Abstract

Introduction Patients diagnosed with a primary cutaneous melanoma are in a higher risk to develop a subsequent melanoma, with an incidence rate that varies from 1.2 to 8.2%. Only a few studies have evaluated the incidence, risk factors and clinical parameters of patients with multiple primary melanomas (MPM) in Mediterranean populations. Aim To study the epidemiological and clinico-pathological characteristics of patients with multiple primary melanomas in a Greek hospital-based cohort. Methods We performed a retrospective study of the medical records of A. Sygros Hospital's Melanoma Unit from 1998 to 2009. Patients with either two or more biopsy-confirmed invasive melanomas or one melanoma in situ and one or more invasive melanomas were included in the study. A detailed questionnaire on risk factors, environmental exposures and family history of cancer was completed. Data on anatomical location, histologic subtype of the tumor and Breslow thickness was obtained for each patient from pathology reports. Results Twelve out of 434 consecutive patients with a primary cutaneous melanoma (2.8%) were subsequently diagnosed with a second primary melanoma. Two of these cases also had a family history of melanoma. Eleven patients had a total of 2 primary melanomas while one patient had three primary tumors. The mean Breslow thickness of the index tumor was 1.46 mm (range 0.52–3.4 mm) and of the 2nd primary tumor was 0.59 mm (0.16–0.95 mm). The mean age at diagnosis was 38 years (range 18–57 years). Seven patients (58%) had Fitzpatrick's skin phototype II. History of high cumulative sun exposure reflected by occupational sun exposure and the presence of actinic keratoses was reported in 3 (25%) and 2 (16%) patients respectively, while recreational exposure and increased sun exposure during childhood (>5 weeks/year) was reported in 8 patients (67%). Eleven patients had dysplastic nevi and 8 out of 11 (86%) had a prominent mole pattern (>50 common nevi). Conclusion The incidence of multiple primary melanomas in Greek patients appears to be lower than that reported in several studies of Northern European populations. Although our sample is small, our findings suggest that patients with multiple nevi or dysplastic nevi and a history of high intermittent exposure to UVR are at a higher risk of developing a secondary primary melanoma. Familial history was not a predominant feature in our MPM patients.