Incidence trends and patterns of breast cancer in Sri Lanka: An analysis of the national cancer database

Abstract

Background: A gradual decline in the incidence of breast cancer is documented in developed countries especially over last two decades, while in developing countries the incidence continues to rise. We conducted this study to examine trends in incidence of breast cancer in a developing country, Sri Lanka. Methods: A retrospective cohort evaluation of patients with breast cancer during 2001-2010 was performed using population based data from the Sri Lanka National Cancer Registry. Trends in incidence were analysed using Joinpoint regression analysis. Results: The age standardized incidence of female breast cancer in Sri Lanka appears to have increased from 17.3 per 100,000 in 2001 (95% confidence interval [95% CI] 16.5-18.2) to 24.7 per 100,000 in 2010 (95% CI 23.7-25.7); a 1.4-fold increase (p<0.05) with an estimated annual percentage change (EAPC) of 4.4 (95% CI 3.3-5.5). Highest incidence of breast cancer was seen among women of 60 to 64-year age group which has increased from 68.1 to 100.2 per 100,000 over this period (EAPC 4.6%, 95% CI 3.9-5.2, p<0.001 for trend). A substantially greater increase was observed among women older than 50 years (from 50.4 to 76.9 per 100,000; EAPC 5.5, 95% CI 4.1-7.0, p<0.05) compared with women younger than 50 years (from 32.0 to 39.6 per 100,000; EAPC 2.3, 95% CI 1.1-3.5, p<0.05). Conclusions: A gradual but a significant increase in the incidence of female breast cancer is observed in Sri Lanka. A rapid rise in the breast cancer incidence among post-menopausal women appears to be the major contributor towards this increase. Improving cancer data collection appears to have been a contributor to the observed increase. However, an inherent increase is also likely as differential rates of increase were observed by age groups. Further research is needed to identify the reasons for the observed increase which may help with future cancer control efforts in Sri Lanka.