Projected cancer incidence rates in Bulgaria, 1968-2017.

Background: Incidence predictions are applicable when planning preventive or screening health care programmes, diagnostic, treatment and rehabilitation facilities. The aim of this study was to predict future (1993-2017) incidence rates of the most common sites of cancer in Bulgaria: breast, cervix and corpus uteri in females, and lung, prostate and stomach in males.

Method: Observed numbers of incident cases in the period 1968-1992 and observed (predicted) population size were employed. Age-cohort and age-cohort-period log-linear models were fitted to the observed data, assuming no change in the observed trends.

Results: The incidence rates for all the studied primary sites, except stomach cancer, were predicted to increase. The observed rates in the period 1988-1992 and the predicted rates in the period 2013-2017 per 100000 were in females: breast-from 38.8 to 64.6, cervix-from 12.8 to 19.3, corpus uteri-from 12.4 to 26.5. In males similar rates were: lung-from 41.0 to 73.8, prostate-from 10.1 to 15.0 and stomach-from 17.5 to 10.2. Due to the increasing incidence rates and ageing of the population the predicted number of new cases in the studied sites of cancer in the period 2013-2017 is 62% higher than that observed in the period 1988-1992.