Stage at diagnosis and stage-specific survival of breast cancer in Latin America and the Caribbean: A systematic review and meta-analysis

BACKGROUND: Female breast cancer is the most common cancer in Latin American and Caribbean (LAC) countries and is the leading cause of cancer deaths. The high mortality-to-incidence ratio in the regions is associated with mainly the high proportion of advanced stage diagnosis, and also to inadequate access to health care. In this study we aimed to systematically review the proportion of advanced stage (III-IV) at diagnosis (p(as)) and the five-year stage-specific survival estimates of breast cancer in LAC countries. METHODS: We searched MEDLINE, Embase, and LILACS (Latin American and Caribbean Health Science Literature) to identify studies, in any language, indexed before Nov 5, 2018. We also conducted manual search by reviewing citations of papers found. p(as) was summarized by random effects model meta-analysis, and meta-regression analysis to identify sources of variation. Stage-specific survival probabilities were described as provided by study authors, as it was not possible to conduct meta-analysis. PROSPERO CRD42017052493. RESULTS: For p(as) we included 63 studies, 13 of which population-based, from 22 countries comprising 221,255 women diagnosed from 1966 to 2017. The distribution of patients by stage varied greatly in LAC (p(as) 40.8%, 95%CI 37.0% to 44.6%; I(2) = 99%; p<0.0001). The heterogeneity was not explained by any variable included in the meta-regression. There was no difference in p(as) among the Caribbean (p(as) 43.0%, 95%CI 33.1% to 53.6%), Central America (p(as) 47.0%, 95%CI 40.4% to 53.8%) and South America (p(as) 37.7%, 95%CI 33.1% to 42.5%) regions. For 5-year stage-specific survival we included 37 studies, comprising 28,988 women from ten countries. Seven of these studies were included also for p(as). Since we were unable to adjust for age, comparability between countries and regions was hampered, and as expected, the results varied widely from study to study. CONCLUSIONS: LAC countries should look to address concerns with early detection and diagnosis of breast cancer, and wherever viable implement screening programs and to provide timely treatment.