National and regional breast cancer incidence and mortality trends in Mexico 2001-2011: Analysis of a population-based database

Introduction: Breast cancer is the most common malignancy in Mexican women since 2006. However, due to a lack of cancer registries, data is scarce. We sought to describe breast cancer trends in Mexico using population-based data from a national database and to analyze geographical and age-related differences in incidence and mortality rates.

Methods: All incident breast cancer cases reported to the National Epidemiological Surveillance System and all breast cancer deaths registered by the National Institute of Statistics and Geography in Mexico from 2001 to 2011 were included. Incidence and mortality rates were calculated for each age group and for 3 geographic regions of the country. Joinpoint regression analysis was performed to examine trends in BC incidence and mortality. We estimated annual percentage change (APC) using weighted least squares log-linear regression.

Results: We found an increase in the reported national incidence, with an APC of 5.9% (95% CI 4.1-7.7, p<0.05). Women aged 60-65 had the highest increase in incidence (APC 7.89%; 95% CI 5.5 -10.3, p<0.05). Reported incidence rates were significantly increased in the Center and in the South of the country, while in the North they remained stable. Mortality rates also showed a significant increase, with an APC of 0.4% (95% CI 0.1-0.7, p<0.05). Women 85 and older had the highest increase in mortality (APC 2.99%, 95% CI 1.9-4.1; p<0.05).

Conclusions: The reporting of breast cancer cases in Mexico had a continuous increase, which could reflect population aging, increased availability of screening, an improvement in the number of clinical facilities and better reporting of cases. Although an improvement in the detection of cases is the most likely explanation for our findings, our results point towards an epidemiological transition in Mexico and should help in guiding national policy in developing countries.