2ND PRIMARY CANCERS IN PATIENTS WITH CARCINOMA IN-SITU OF THE UTERINECERVIX - THE NORWEGIAN EXPERIENCE 1970-1992

Multiple primary cancers in the same individual occur rarely. Conseque ntly, a large number of cancer patients have to be followed for long p eriods to obtain adequate information about their risk of subsequent t umour development. Studies of multiple malignancies are of interest, s ince they may provide information on common or opposite risk factors. In the present study, the risk of second primary cancers following car cinoma in situ of the uterine cervix diagnosed in Norway in the period 1970-1992 was examined and quantified. Altogether, 37,001 patients wi th carcinoma in situ were followed from the date of diagnosis until 31 December 1992. The follow-up period was divided into 5-year intervals . The results were expressed as standardized incidence ratios (SIR = O /E), and their 95% confidence intervals were given. A total of 1,037 s econd primary cancers in 989 individuals were identified. There was no overall excess of second primary cancers. However, there were differe nces depending on the site: cancers of the oesophagus, nose, nasal cav ities, trachea, bronchus, lung, vulva, vagina, bladder and other urina ry organs, and other skin cancers, excluding basal-cell carcinoma, occ urred move frequently. A lower risk than expected was noted for cancer of the cervix uteri and cancer of the corpus uteri. There was a risin g trend with time in the observed/expected ratio for cancer of urinary organs. In the group of patients evaluated, the likelihood of subsequ ent tumour development was no greater than in the general female popul ation. Nevertheless, cancer sites of higher and of lower risk than exp ected weve identified among the carcinoma-in situ patients. (C) 1995 W iley-Liss, Inc.