INCIDENCE OF CUTANEOUS MELANOMA IN THE CENTER OF ITALY - ANATOMIC SITE DISTRIBUTION, HISTOLOGIC TYPES AND THICKNESS OF TUMOR INVASION IN A REGISTRY-BASED STUDY

The majority of epidemiological data on cutaneous melanoma (CM) derive s from studies carried out in a predominantly fair-skinned population. On the contrary, little is known of the epidemiological figures (incl uding incidence data) in mediterranean populations. The aim of this st udy was to investigate the incidence rates of CM in a geographically-d efined area of the centre of Italy, with particular attention to anato mic site distribution, histologic types and thickness of tumour invasi on. After revision of the data base of the Tuscany Cancer Registry con cerning the period 1985 to 1987, 282 incident cases of invasive CM (13 5 males, 147 females) were found in a resident population of 1,174,121 inhabitants. The mean annual age-standardized rates were 6.7/100,000 for males and 7.0/100,000 for females. Site-specific incidence rates s howed an almost three-fold higher incidence of CM of the trunk in male s than females (3.7/100,000 vs 1.4/100,000). Conversely, a four-fold h igher incidence in females than in males was observed for the lesions of lower limb (2.1/100,000 vs 0.5/100,000). A statistically significan t difference of incidence rates was also observed for the thigh (femal es 1.1/100,000, males 0.2/100,000), a normally sun-exposed area. Conce rning histologic types of CM, the incidence of the nodular type was hi gher in males than in females (1.8/100,000 vs 1.3/100,000), even if th e difference was not statistically significant in any class of age. Th e most interesting finding of this study was related to the difference of the thickness of tumour invasion between sexes at the time of diag nosis: lesions with favourable prognosis (less than 0.75 mm in thickne ss) were more frequent in females than in males (1.4/100,000 vs 0.3/10 0,000); on the other hand, incidence rates of poor prognosis CM (> 3.0 mm) were higher in males than in females (2.1/100,000 vs 1.0/100,000) . This study shows that in mediterranean populations the specific inci dence rates for age and anatomic site are similar to a predominantly f air-skinned population, whereas the overall incidence is lower. In res pect of the peculiarity of each sex, the striking difference between m ales and females of the thickness of tumour invasion at diagnosis shou ld be considered to better tailor further information for secondary pr evention.