Abstract P3-07-15: Recent changes in breast cancer incidence and mortality trends in Mexico: A population-based study
Authors: Soto-Perez-de-Celis Enrique , Mohar Alejandro , Chavarri-Guerra Yanin 
Published: May 2015

Background: Breast cancer (BC) is the most common malignancy in Mexican women since 2006, with a high number of cases reported in the more developed northern states. However, the analysis of national BC incidence in Mexico has not been previously reported. We sought to describe BC trends in Mexico using recent population-based data and to analyze geographical differences in BC incidence and mortality rates.

Methods: This population-based retrospective cohort study included all incident BC cases registered in the National Epidemiological Surveillance System and all BC deaths registered by the National Institute of Statistics and Geography in Mexico from 2001 to 2011. Yearly populations were obtained from national census data. The age-standardized (AS) incidence rate of BC was calculated using the female population over 15 years of age and standardized to the World Standard Population. AS incidence rates were calculated for 3 geographic regions of the country (North, Center and South). 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: From 2001 to 2011, 69,651 new cases of BC were registered in Mexico. The AS incidence of BC significantly increased, rising from 14.2/100,000 person-years (PY) (Standard Error [SE] 0.23) in 2001, to 25.2/100,000 PY (SE 0.25) in 2011, with an APC of 5.9% (95% CI 4.1-7.7, p&lt;0.05). Regional AS incidence rates were significantly increased in the Center and in the South, with a non-significant increase in the North (Table 1). For the same period, 48,817 deaths attributed to BC were registered. AS mortality rate also had a significant increase, rising from 14/100,000 PY (SE 0.23) in 2001 to 14.6/100,000 PY (SE 0.2) in 2011, with an APC of 0.4% (95% CI 0.1-0.7, p&lt;0.05). Regional AS mortality rates were significantly increased in all three regions (Table 1).

Table 1. Regional BC incidence and mortality ratesRegion2001 AS rate per 100,000 PY (SE)2011 AS rate per 100,000 PY (SE)APC% (95% CI)pSouthIncidence6.1 (0.42)16.57 (0.53)10.5 (6-15.2)&lt;0.05Mortality7.8 (0.46)9.56 (0.43)2 (1-3.2)&lt;0.05CenterIncidence12.9 (0.27)26.9 (0.33)7.6 (5.7-9.6)&lt;0.05Mortality14 (0.29)14.4 (0.25)0.3 (0-0.6)&lt;0.05NorthIncidence24.2 (0.64)26.8 (0.54)1 (-1.6-3.7)NSMortality17.6 (0.57)18.8 (0.48)0.7 (0-1.3)&lt;0.05

Conclusions: BC trends in Mexico show a continuous increase in incidence and mortality from 2001 to 2011, which could reflect population growth, ageing, lifestyle modifications and changes in access to diagnosis and treatment. These changes could be an expression of epidemiological transition in developing countries such as Mexico. A significant growth in both incidence and mortality was found in both the Center and the South. In the North, incidence rates remained unchanged while mortality rates had a significant rise, which was comparable to that of the other regions. One possible unexplored explanation for this observation could be the recent wave of drug-related violence and high criminality rates in the north of the country, which may perhaps cause underreporting of cases and disrupt availability of medical attention and access to healthcare in an otherwise developed and wealthy region.

Citation Format: Enrique Soto-Perez-de-Celis, Alejandro Mohar, Yanin Chavarri-Guerra. Recent changes in breast cancer incidence and mortality trends in Mexico: A population-based study [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P3-07-15.