Abstract

Cancer affects millions of people each year worldwide and represents a major challenge for healthcare systems. Information based on populational data, such as Cancer Registries, are essential to endorse health planning and provision of cancer care services. This paper aims to present a data quality evaluation of breast cancer incidence data from the Population Based Cancer Registry of the Municipality of São Paulo, Brazil. The study included 46 311 new breast cancer cases recorded during a two 5-year periods (1997–2001 and 2002–2006). Data analysis was focused on variables such as: date and age at diagnosis, clinical stage, topographic distribution and tumour morphology. For women aged between 40 and 69 years, the most common diagnosis was the malignant neoplasm of breast, unspecified (ICD-10 C50.9), (87,6% of all cases), which does not specify clearly the topography and extent of disease. Problems of information completeness for important variables such as clinical and pathological staging were identified on time-series analysis. Hence, data quality of cancer registries are crucial for breast cancer survival analysis as well as for planning cancer control policies, enhancements on data collection are required.