Rectal cancer incidence in Arkhangelsk region: trends and short-term prognosis by the data of the Arkhangelsk regional cancer registry

Introduction. More than 1 million new cases of rectal cancer (RC) are annually detected worldwide, and together with colon cancer this tumor is the 4th most frequent cause of cancer death. objective: To analyze short-term prognosis of RC incidence for certain population subgroups in the Arkhangelsk region, Russia. material and methods. The data on all primary RC cases in the Arkhangelsk region in the time period from 2000 to 2015 were selected. Crude (whole population) and age-standardized incidence rates were calculated depending on gender and place of residence (urban or rural). The ARIMA model (autoregressive integrated moving average) was chosen to analyze the variations of the time series and to estimate prognosis. To transform the series to a stationary form and to reduce dispersion, the first or second differences of their values and the natural logarithms were taken. The incidence values for the period 2016-2018 were predicted on stationary series of RC incidence from 2000 to 2015. results. Crude and age-standardized RC incidence rates in Arkhangelsk region increased from 14.4 and 11.4 in 2000 to 23.5 and 15.1 per 100,000 in 2015. Age-standardized RC incidence rates for males, females, urban and rural populations increased from 14.8, 10.1, 9.3 and 15.1 to 20.3, 12.6, 12.3 and 20.4 per 100, 000, respectively. Actual values of incidence rates among all population, male/female and rural/urban population in 2015 were within the confidence interval of the prognosis. The constructed prognosis model assumes an increase in the RC incidence among all population groups, which may cause the detection of 279 new cases by 2018; i.e. 16 cases (6%) more than in 2015. conclusion. The incidence rates of RC have been steadily increasing in all population groups, and the rate of growth depends only partly on the population ageing. The number of new patients is expected to increase by 6 % in 2018.