Mongolian Breast Cancer Incidence: A Follow-up Report.

Objective: Understanding variance in global breast cancer incidence rates may help identify risk factors and could lead to increased efforts for prevention. In our previous study on breast cancer in Mongolia from 1998-2005, we reported that the incidence of breast cancer, though on the rise, remains lower in Mongolia than in adjacent Asian countries. Through the addition of almost a decade of data (2006-2014), we provide a study update and describe trends in breast cancer incidence and staging distributions within Mongolia, with further analyses examining women in urban and rural regions. Methods: Age-standardized breast cancer incidence and staging distributions were obtained from the Mongolian National Oncology Center and were used to describe trends in cancer over time. Results: Our findings indicate that the overall incidence of breast cancer has continued to increase in Mongolia, with rural women still experiencing lower risk than their urban counterparts. Given similarities in cancer staging, the observed geographic variation does not appear to result from differences in cancer stage at diagnosis over time or by region. Conclusions: Considering the variation in rural and urban populations, data from this study could be used to better understand the influence of westernization on cancer risk in Asian countries and beyond. Further research on demographic shifts in breast cancer incidence within Mongolia may elucidate novel risk factors explaining variations active among other populations.