Twelve contiguous regional cancer registries are responsible for collecting and collating data on all incident cancers in the UK using data supplied by hospitals, including pathology departments.¹ All death certificates mentioning cancer are returned to the appropriate registry to enable date of death to be recorded. In the event that this procedure identifies a cancer that has not been previously entered on the register, a death certificate initiated registration occurs and attempts are made to collect clinical data retrospectively. If no such data can be found (for example, if medical records have been lost or destroyed), a death certification only (DCO) registration occurs.

A recent review of UK cancer registry data concluded that “there are clear grounds for supposing that cancer registry records are largely complete, accurate and reliable”.² Although there is some evidence that DCO registrations are more common in deprived populations,³ little previous research has investigated whether there are socioeconomic variations in the quality of other aspects of cancer registration data. Such variations may reflect socioeconomic variations in cancer care—one area of concern highlighted by the white paper, Our Healthier …