Sociodemographic determinants of incidence of primary fallopian tube carcinoma, Finland 1953-97

Primary fallopian tube carcinoma is very rare. In Western countries, it accounts for about 1% of all female genital malignant tumors. Its etiology remains poorly known, but high parity is considered to be protective. We studied determinants of incidence of primary fallopian tube carcinoma in Finland. Incidence rates for primary fallopian tube carcinoma, according to the population based Finnish Cancer Registry, from 1953- 97 were assessed by age, year of diagnosis, and type of residential area. Standardized incidence ratios (SIRs) for the years 1971-95 were calculated by occupation and social class variables taken from the 1970 Population Census. There were 485 cases of primary fallopian tube carcinoma registered during 45 years. The age-adjusted incidence rate increased from 1.2/1,000,000 in 1953-57 to 5.4/ 1,000,000 in 1993-97. This 4.5-fold increase in incidence rate corresponds to a 7-fold increase in the number of new cases. The increase is attributable to the age group beyond 55 years, the peak incidence occurring between 60-64 years. Although the relative increase in incidence rate has been larger in rural areas than in cities, the rate in the latter remains 2-fold. Women in the 2 highest social classes had a 1.8-fold incidence (95% CI = 1.2-2.6) as compared to the lowest social class. Women in agriculture and those not working outside the home had only half the cancer incidence of those in academic or clerical occupations. The incidence of primary fallopian tube carcinoma increases in Finland. Evidently, the incidence has increased simultaneously with the affluence of urban life. Part of the variation in incidence correlates with variation in parity. (C) 2003 Wiley-Liss, Inc.