Breast Cancer Incidence Trends in Isfahan Province Compared with those in England over the Period 2001-2013

Abstract

Background: Figures from Iranian cancer registries indicate that Isfahan ranks first in female breast cancer incidence. Although few previous studies have examined whether the breast cancer incidence trend in Isfahan province has increased over a given period of time, this study employed a joint point regression analysis to answer the same question. Moreover, it compared the data of Isfahan province, from a developing country, with those of England, as a representative of developed countries, and tried to explain the causes of the differences observed between the trends. Methods: This repeated cross-sectional study was conducted on the data of 6057 women in Isfahan province and of 141,011 women in England with breast cancer over the years 2001-2013. The incidence rates were calculated using direct standardization method and based on the 2013 standard European population. For an analysis of the trends in breast cancer incidence rates, Joint Point Regression program, version 4.3.1.0, released in April 2016, was employed. Results: The mean age-standardized incidence rate (ASR) was calculated to be 34.7 per100,000 population over the years 2001 to 2013, which indicated an increase from 22 to 68 in Isfahan province. The corresponding mean ASR for England has also risen from 147.5 to 170.1 per 100,000 women during the same time period. The average annual percentage changes (AAPCs) for Isfahan and England were also calculated to be 9.6 and 1.1, respectively. This indicated an increasing trend in breast cancer incidence rates for Isfahan province over the period in question. Conclusions: The drastic discrepancy in breast cancer incidence rates between these two regions may be attributed to differences in an improved cancer registry system in Iran and women's developing awareness of the cancer over time.