Characteristics of Synchronous- and Metachronous-Type Multiple Primary Neoplasms: A Study of Hospital-Based Cancer Registry in Turkey

PurposeThe 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 MethodsFive 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. χ2 and Student t test were performed.ResultsOne 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).ConclusionField 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.