Retrospective cohort study of breast cancer incidence, health service use and outcomes in Europe: a study of feasibility.

Background: Comparisons of outcomes of health care in different systems can be used to inform health policy. The EuroHOPE (European Healthcare Outcomes, Performance and Efficiency) project investigated the feasibility of comparing routine data on selected conditions including breast cancer across participating European countries.

Methods: Routine data on incidence, treatment and mortality by age and clinical characteristics for breast cancer in women over 24 years of age were obtained (for a calendar year) from linked hospital discharge records, cancer and death registers from Finland, the Turin metropolitan area, Scotland and Sweden (all 2005), Hungary (2006) and Norway (2009). Age-adjusted breast cancer incidence and 1-year survival were estimated for each country/region.

Results: In total, 24 576 invasive breast cancer cases were identified from cancer registries from over 13 million women. Age-adjusted incidence ranged from 151.1 (95%CI 147.2-155.0) in Hungary to 234.7 (95%CI 227.4-242.0)/100 000 in Scotland. One-year survival ranged from 94.1% (95%CI 93.5-94.7%) in Scotland to 97.1% (95%CI 96.2-98.1%) in Italy. Scotland had the highest proportions of poor prognostic factors in terms of tumour size, nodal status and metastases. Significant variations in data completeness for prognostic factors prevented adjustment for case mix.

Conclusion: Incidence of and survival from breast cancer showed large differences between countries. Substantial improvements in the use of internationally recognised common terminology, standardised data coding and data completeness for prognostic indicators are required before international comparisons of routine data can be used to inform health policy.