Key words: cancer registry, inci- dence, multiple primary cancers, prostate cancer. Acknowledgments: This work was supported by the Department of Health, Regional Government of Um- bria, Italy. Correspondence to: Dr Tiziana Casset- ti, Department of Medical-Surgical Specialities and Public Health, Public Health Section, University of Perugia, Via del Giochetto, 06100 Perugia, Italy. Tel +390755857335; fax +390755857317; e-mail tiziana.cassetti@unipg.it Received January 10, 2007; accepted March 2, 2007. Metachronous malignancies in men with previous prostate cancer in Umbria, Italy, 1994-2003 Tiziana Cassetti, Fabrizio Stracci, Liliana Minelli, Massimo Scheibel, Ida Elena Sapia, and Francesco La Rosa Umbrian Population Cancer Registry, Department of Medical-Surgical Specialties and Public Health, Public Health Section, Perugia University, Perugia, Italy ABSTRACT Data about second primary tumors after prostate carcinoma are controversial. Some authors emphasize an increased incidence of some cancer sites, others an overall diminution. With the aim to provide further information to define the issue, we have analyzed the frequency of second metachronous primary malignancies in patients with diagnosed prostate cancer in the Umbria region of Italy. A total of 410 metachronous cancers among 4528 prostate cancer patients were abstracted from incident cases of the RTUP, over the period 1994-2003. This cohort was compared with all cases (except prostate cancers) recorded in the RTUP archive. The expected number of cases was obtained from indirect standardization with regional inci- dence rates of several sites. The significance of the observed/expected ratios and the corresponding 95% confidence intervals were based on the Poisson distribu- tion. A significant standardized incidence ratio was found for all sites but prostate, with 410/351 observed/expected cases. The significance disappears considering all sites except prostate and skin non-melanomas. Among several sites, significant standardized incidence ratios were found for skin non-melanomas, for bladder, for rectum, but not for colon cancers. Kidney, ureter and urethra showed a nonsignifi- cant standardized incidence ratio. Nasopharynx showed a significant standardized incidence ratio, but the result was based on a very small number of cases. In our da- ta, the increase in urinary bladder and rectal cancers, after prostate cancer diagno- sis, seems to be real: it is plausible that the number of second cancers may be due to increased urologist surveillance, which, in our Region, does not seem to be re- duced in elderly men. Introduction The last report of the Italian Association of Cancer Registries 1 indicated that prostate cancer incidence in Italy currently accounts for 14.4% of total newly diag- nosed cancers, second only to skin cancer (15.2%), whereas the mortality is second to lung cancer (14.5% vs 28.3%). In the age group over 65 years, prostate cancer inci- dence ranks first. Very similar patterns in incidence and mortality were reported by the Umbrian Population Cancer Registry (RTUP) for the Umbria region of Italy in the last few years 2 . In the period 1994-2003, the RTUP registered 4228 new cases and 1500 deaths from prostate cancer, with an increasing trend of crude rates in both incidence and mortality, due mainly to aging of the male population and to diffusion of oppor- tunistic screening practices 2-4 . Data about second primary tumors after prostate carcinoma are controversial, es- pecially regarding the increased incidence of some sites deriving from irradiation of the prostate, particularly bladder cancer 5-9 . Singh et al. 10 reported a statically signifi- cant standardized incidence ratio (SIR) of 5.63 of a second cancer of the bladder in men affected by prostate cancer, not related to irradiation. In contrast, a reduction in overall risk of multiple tumors has been reported by several authors 11-13 . Levi et al. 11 Tumori, 94: 7-10, 2008