Effect of improved data collection on breast cancer incidence and survival: reconciliation of a registry with a clinical database.

In 1998 a project was undertaken to improve cancer registration in the Trent region by establishing a direct link between Trent Cancer Registry and a breast cancer clinical database for Leicestershire patients at Glenfield Hospital. This provided an opportunity to study registrations for 1997 to determine how many and who were missed. We then estimated the effect of improved ascertainment on incidence and survival.

Methods and results

Throughout 1998 Trent Cancer Registry sent registrations for 1997 to Glenfield Hospital for comparison. We investigated three main issues.

* Differences in recorded date of diagnosis, including identification of an earlier date of diagnosis for patients registered as diagnosed at the time of death (that is, where diagnosis is based solely on death …