Abstract 1596P
Background
Breast is the most frequent cancer in Europe among women. Stage is a powerful indicator of prognosis and for understanding cancer outcomes. Screening programmes aims at detecting tumours at an early stage so affecting the stage distribution of cases. The aims of this study are to validate the stage information as directly collected from European cancer registries (CRs), and analyse breast cancer stage migration over time.
Methods
Female invasive breast carcinomas in the age group 50-69 were selected from 37 population-based CRs contributing to the European Cancer Information System, covering a registration period of at least 10 years and reporting stage. Data related to stage were: TNM stage grouping - pathological/clinical TNM values - condensed TNM - summary extent of disease. After the harmonisation of these variables, stage was computed as a summary indicator following priorities previously established. The “calculated stage” was compared with the stage provided by CRs.Trends of the proportions of stage I and stage IV were analysed and the Average Annual Percent Change (AAPC) was calculated using the Joinpoint Trend Analysis Software.
Results
813,286 cases were extracted, ranging from year 1976 to 2014. From the variables submitted, it was computed stage for 91% of the cases.The concordance between calculated stage and the stage reported by the CRs was 61%. Discordance was explained for 34% of cases due to stage missing values reported by the CRs which could be completed considering other variables. In 2013, the proportion of stage I in the selected CRs ranged 27% - 63%. The AAPC of stage I increased over time in 22 CRs. The AAPC increase ranged from 0.6% (0.1-1.1) to 7% (5.6-8.5). The proportion of stage IV ranged 3.3% - 27%. A decrease in the AAPC of stage IV was observed in 30% of the CRs (11). The AAPC decrease ranged from 2.1% (0.2-4.0) to 5.8% (0.6-10.8).
Conclusions
Calculated stage was in agreement with stage reported by the CRs when not missing values. This study showed variations in stage migration among the European CRs. Further studies are needed to explain such differences and their possible association with factors related to screening programmes. Harmonisation of stage data is needed to improve comparability among European countries and regions.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
Joint Research Centre. European Commission.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.