Time trends of breast cancer survival in Europe in relation to incidence and mortality

Abstract

Increasing breast cancer survival, observed in most western countries, is not easily interpreted: it could be due to better treatment, more effective treatment due to earlier diagnosis or simply lead-time bias. Increased diagnostic activity (e.g., screening) can inflate both incidence and survival. To understand interrelations between incidence, mortality and survival trends and their consequences, we analyzed survival trends in relation to mortality and incidence. Starting with observed survival from EUROCARE, mortality from WHO and using the MIAMOD method, we estimated breast cancer incidence trends from 1970 to 2005 in 10 European countries. To smooth out peaks in incidence and survival due to early diagnosis activity, survival trends were assumed similar to those observed by EUROCARE in 1983-1994. The following patterns emerged: (1) increasing survival with increasing incidence and declining or stable mortality (Sweden, Finland); (2) slight survival increase, marked incidence increase and slight mortality decrease (Denmark, the Netherlands and France); (3) increasing survival, marked decrease in mortality and tendency to incidence stabilization (UK); (4) marked survival increase, steady or decreasing mortality and moderate increases in incidence (Spain, Italy); (5) stable survival, increasing incidence and mortality (Estonia). In most countries survival increased, indicating a real advantage for patients when accompanied by decreasing or stable mortality, and attributable to improved cancer care (Sweden, UK, France, Italy and Spain). In Finland (with high survival), the Netherlands and Denmark, increasing mortality and incidence indicate increasing breast cancer risk, probably related to life-style factors. In Estonia, low and stable survival in the context of increasing incidence and mortality suggests inadequate care.