Adjustment of incidence rates after an estimate of completeness and accuracy in registration of acute leukemias in a Swedish population

Earlier studies have revealed undernotification of hematological malignanci es in Swedish and other Cancer Registries. We present epidemiological data on AML, ALL and unspecified AL in adults diagnosed 1987-1992 in a well-defi ned population, Blast crises of CML were excluded. The Swedish Cancer Regis try and Cause of Death Registry were compared and patient records reviewed for validation. When available, listings of pathology bone marrow reports a nd inpatient discharge diagnoses were utilized for casefinding. 260 cases o f acute leukemias could be verified in a population of 663,135 adults, corr esponding to a yearly incidence of 6.5/100,000. The median age of the patie nts was 69.2 years, 214 cases were AML, 38 ALL and eight unspecified AL. Un dernotification in the Cancer Registry was found to be 15.4%, greater for A ML and unspecified AL than for ALL. In addition the coding was not uniform, resulting in an incidence rate in adults of 5.3/100,000 for the Cancer Reg istry which is 18.5% lower than that of our study. A significant survival a dvantage was seen for notified patients. Combination of the Cancer Registry and Cause of Death Registry gave acceptable coverage, omitting only four p atients. As the incidence of acute leukemias in our study is comparatively high, we hypothesize that underestimation of incidence and overestimation o f survival are general problems for cancer registries.