RESUMEN
PURPOSE: The aim of this study was to evaluate the demographic, histologic, and topographic characteristics, and the association of synchronous and metachronous multiple primary neoplasms. PATIENTS AND METHODS: Five hundred seventy-two multiple primary tumors (n = 286) of 20,895 tumors recorded from 1993 to 2005 by the office of Izmir Cancer Registry at the Izmir Ataturk Training and Research Hospital were analyzed. chi(2) and Student t test were performed. RESULTS: One hundred fifty-eight patients had synchronous tumors whereas 128 had metachronous tumors. Both groups were more frequent among men and among patients aged > 50 years. The distribution of synchronous and metachronous tumors between sex and age groups was similar (P = .462 and P = .479, respectively). Carcinomas were more frequent and histologic compositions of both of the groups were significantly different (P = .009). Pairs of the same topographic origin were significantly more frequent in synchronous tumors (P = .019). The urogenital system was the most frequent location in all groups. The leading tumoral association was between urogenital-urogenital tumors, also. Detailed evaluation of the metachronous group revealed that the most frequent organ associations were of breast-ovary (n = 7) and bladder-larynx (n = 5). CONCLUSION: Field cancerization in the epithelium, theory of a common clonal origin, or the screening effect might account for the relatively frequent association of urogenital tumors. The association of the tumors of breast-ovary might be related to the endocrine effect. Further studies complying with international rules and using data from different population-based tumor registries are necessary to elucidate site correlation.