BREAST-CANCER AS CAUSE OF DEATH - A STUDY OVER THE VALIDITY OF THE OFFICIALLY REGISTERED CAUSE OF DEATH IN 2 631 BREAST-CANCER PATIENTS DYING IN MALMO, SWEDEN 1964-1992

The validity of registered official cause of death (GOD) concerning br east cancer patients in Malmo 1964-1992 was analysed, There was a high frequency of autopsy in the material and, therefore, the number of di agnostic errors should be low, Found discordance thus mostly reflect t he quality of certifying and registration of GOD. Of 2 631 deaths disc ordance was found as to underlying COD in 121 cases (4.6%), Ninety-fou r of these represent outright errors, In 27 there was doubt about the reported GOD. The number of discordant cases increased with age at dea th, Two kinds of systematic bias were found, One was a tendency to rep ort breast cancer as contributing COD in patients with clinical cure, The other was a practice at the Registry to register breast cancer as underlying COD in cases with breast cancer reported as contributing GO D. This practice was changed in 1981 causing an artificial decrease in registered breast cancer mortality.