Linking data from hospital and cancer registry databases: should this be standard practice?

BACKGROUND: Varying amounts of data related to cancer diagnosis, treatment and/or outcome are routinely collected by many disparate groups. Routinely combining data from these sources could improve data quality and utility for audit and research purposes. The aim of this study is to demonstrate the benefits of linkage between oncology databases. METHODS: We examined colorectal cancer (CRC) data recorded by the Victorian Cancer Registry and two hospital clinical databases between January 2000 and December 2005. Where data were in common, the completeness and accuracy of each dataset were examined. Where content differed, the potential value of making this additional data available to the other database was examined. RESULTS: Of the 831 cases recorded at the hospitals, 822 (98.9%) were also recorded on the cancer registry. Eight of the 913 cases (0.87%) recorded as having CRC by the registry did not have CRC. Errors in recording of tumour site and tumour or nodal stage were frequent in both databases. Metastasis stage was recorded in only 29 of 822 (3.5%) registry cases examined. Discordance for diagnosis date and death date was also frequent, although the difference was typically minor. Adding additional death data from the registry to the clinical database significantly altered stage-specific and overall survival figures. CONCLUSION: A multidirectional flow of data between hospital and registry databases provides multiple opportunities to improve data quality and utility. While issues around data ownership and usage need to be considered, the advantages of routine data linkage are readily apparent.

Monitoring interval cancers in an Australian mammographic screening programme.

OBJECTIVE: To report the interval cancer rate for BreastScreen Victoria. DESIGN: Electronic linkage of Breast Screen Victoria records with those of the Victorian Cancer Registry. Interval cancers were expressed as a proportion of the underlying incidence (proportional incidence), and the sensitivity as the number of screen detected invasive breast cancers divided by the total number of invasive breast cancers diagnosed in the screening interval. SETTING: Victoria, Australia where biennial screening is provided to women aged 40 and older. SUBJECTS: Victorian women aged 40-79 who attended first round screening in 1994 (103,023 women) and 1995 (107,057 women). RESULTS: The sensitivity of screening mammography for the two year interval increased with age (p for trend < 0.001) and was 49.4% in women aged 40-49, 68.6% in 50-59 year old women, 80.7% in 60-69 year old women, and 85.2% in women aged 70-79. The proportional incidence in the first year after screening was 59% in 40-49 year old women and 27% in women aged 50-69. In the second year the proportional incidence was 93% in 40-49 year old women and 54% in women aged 50-69. CONCLUSIONS: Interval cancers comprise such a large proportion of the expected number of cancers in 40-49 year old women that the benefit of screening is likely to be low. For women aged 50-69, the proportional incidence found in this study was similar to those found in the UK programmes.

Childhood cancer in Victoria, Australia, 1970-1989.

The incidence of cancer between 1970 and 1989 in children aged less than 15 years and resident in the state of Victoria, Australia, was ascertained using records held by the Victorian Cancer Registry. Altogether, 1,189 children in the 1970s and 1,261 children in the 1980s were registered with new diagnoses of cancer and these were followed up until 30 June 1993. Between 1970-1979 and 1980-1989 the incidence of childhood cancer rose by 14%, but this was not statistically significant. Part of this apparent increase may have been due to improved registration of cases in the 1980s, particularly of certain tumour types, and of tumours in older children who may have been treated outside the major paediatric treatment centres. Between the 2 decades, 5-year survival increased from 49% to 67%, with improvements in almost all tumour types. Only in Ewing's sarcoma did survival proportions decrease, and this may be related to histological misclassification and to an increased proportion of Ewing's arising in the pelvis during the 1980s. There is evidence already that with new treatment regimens introduced during the 1980s survival in the 1990s will show increased gains.

Primary tumors of the brain, cranial nerves and cranial meninges in Victoria, Australia, 1982-1990: patterns of incidence and survival.

This report presents for the first time a detailed analysis of the distribution of primary brain tumors in a population in Australia. Data on 3,575 cases of benign and malignant tumors of the brain, cranial nerves and cranial meninges diagnosed among residents of the state of Victoria from 1982 to 1990 are used to calculate incidence rates and survival by histologic type, age and sex and to compare incidence of birthplace, socioeconomic status and year of diagnosis. No sharp decline in incidence rates is seen among those over age 60 and only small increases in incidence over the 9-year period have been observed. The overall incidence rates, distributions by histologic type, and patterns of excess incidence among those born in Southern and Eastern Europe and the Middle East are similar to observations in other geographic areas. No clear trend relating incidence and socioeconomic status is observed. Survival after brain tumor diagnosis is better among women then men (52 vs. 37% survive 5 years); this difference is attributable to the greater frequency among men of the more aggressive tumor types. The most striking male over female excess is for medulloblastoma, a type that occurs predominantly in the pediatric age group. This excess coupled with the fact that this tumor occurs at a much younger age in males may suggest the presence of a genetic predisposition in some patients with this disease.