title: Melanoma density and relationship with the distribution of melanocytic naevi in an Italian population: a GIPMe study--the Italian multidisciplinary group on melanoma.
abstract: The most frequent site for melanoma is the back in men and the lower limbs in women, where intermittent sun exposure has been reported to be an environmental agent, although studies on age-specific incidence have suggested that melanoma in chronically sun-exposed areas, such as the face, increases with age. To identify the preferential development of melanoma in chronically or intermittently sun-exposed areas and the relationship between body site distribution and parameters such as sex, age, distribution of melanocytic naevi, atypical naevi and actinic keratoses, a prospective epidemiological multicentre study was carried out on all the consecutive melanoma cases diagnosed in a 2-year period from 27 Italian GIPMe centres (GIPMe: the Italian Multidisciplinary Group on Melanoma). Both the relative density of melanoma (RDM), defined as the ratio between observed and expected melanoma for a specific body site, and the average nevi density were identified. The most common melanoma site was the back, a factor that was not affected by either age or sex, even if men had higher density values. Statistically significant higher RDM values were observed in women aged more than 50 years for leg lesions and in the anterior thighs for young women (<50 years), whereas the lowest values were observed in the posterior thighs in women of any age. Facial RDM was statistically significantly higher than expected in both male and female patients more than 50 years of age. Melanoma was associated with a significantly higher atypical naevi density only for the back, chest and thighs. Indeed, facial melanoma was related to the presence of more than four actinic keratoses and not naevi density. To the best of our knowledge, the RDM method was applied for the first time together with naevus density calculation to obtain these data, which strongly substantiate the 'divergent pathway' hypothesis for the development of melanoma, but not find a direct correlation between melanoma and nevi for each anatomical site.
authors.affiliation: aSecondary Prevention and Screening Unit bClinical and Descriptive Epidemiology Unit, Institute for Study and Cancer Prevention (ISPO) cDepartment Surgery and Translational Medicine, Dermatology Division, University of Florence Medical School dPlastic Surgery Unit, Regional Melanoma Referral Centre, S. Maria Annunziata Hospital, Florence eSection of Dermatology, Department of Biomedical Sciences and Human Oncology, University of Turin, Turin fDepartment of Dermatology, University of Brescia, Brescia, Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Chiarugi
authors.forename: Pietro
authors.initials: P
authors.lastname: Quaglino
authors.forename: Emanuele
authors.initials: E
authors.lastname: Crocetti
authors.forename: Paolo
authors.initials: P
authors.lastname: Nardini
authors.forename: Vincenzo
authors.initials: V
authors.lastname: De Giorgi
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Borgognoni
authors.forename: Paola
authors.initials: P
authors.lastname: Brandani
authors.forename: Gianni
authors.initials: G
authors.lastname: Gerlini
authors.forename: Ausilia Maria
authors.initials: AM
authors.lastname: Manganoni
authors.forename: Maria Grazia
authors.initials: MG
authors.lastname: Bernengo
authors.forename: Nicola
authors.initials: N
authors.lastname: Pimpinelli
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D005260:Female; D006801:Humans; D015994:Incidence; D007558:Italy / Q000453:epidemiology; D008297:Male; D008545:Melanoma / Q000453:epidemiology / Q000473:pathology*; D008875:Middle Aged; D009508:Nevus, Pigmented / Q000453:epidemiology / Q000473:pathology*; D011446:Prospective Studies; D012307:Risk Factors; D012737:Sex Factors; D012871:Skin Diseases / Q000453:epidemiology / Q000473:pathology; D012878:Skin Neoplasms / Q000453:epidemiology / Q000473:pathology*; D016896:Treatment Outcome