Validation of primary and outcome data quality in a Swedish population-based breast cancer quality registry

Sofia Palmér; Carl Blomqvist; Marit Holmqvist; Henrik Lindman; Mats Lambe; Johan Ahlgren

doi:10.1186/s12885-024-12073-4

Validation of primary and outcome data quality in a Swedish population-based breast cancer quality registry

BMC Cancer. 2024 Mar 11;24(1):329. doi: 10.1186/s12885-024-12073-4.

Authors

Sofia Palmér¹, Carl Blomqvist^{2

3}, Marit Holmqvist⁴, Henrik Lindman⁵, Mats Lambe^{4

6}, Johan Ahlgren^{2

4}

Affiliations

¹ Department of Oncology, Faculty of Medicine and Health, Örebro University Hospital, Örebro University, Örebro, SE-70182, Sweden. sofia.palmer@oru.se.
² Department of Oncology, Faculty of Medicine and Health, Örebro University Hospital, Örebro University, Örebro, SE-70182, Sweden.
³ Comprehensive Cancer Center, Helsinki University Hospital and University of Helsinki, Helsinki, Finland.
⁴ Regional Cancer Center Central Sweden, Uppsala University Hospital, Uppsala, Sweden.
⁵ Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden.
⁶ Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden.

Abstract

Background: Population-based cancer quality registries are of great importance for the improvement of cancer care. However, little is known about the quality of recurrence data in cancer quality registries. The aim of this study was to evaluate data quality in the regional Breast Cancer Quality Registry of Central Sweden, with emphasis on the validity of recorded information on recurrence.

Methods: Validation by re-abstraction was performed on a random sample of 800 women with primary invasive breast cancer stage I-III diagnosed between 1993 and 2010, of which 400 had at least one registered recurrence and 400 had no registered recurrence. Registry data were compared with data from medical records. Exact agreement, correlation and kappa values, sensitivity and specificity were calculated.

Results: Seven hundred forty-seven women (93%) were available for analysis. Exact agreement was high for diagnostics, tumor characteristics, surgery, and adjuvant oncological treatment (90% or more for most variables). The registry's sensitivity was low for regional recurrence (47%), but higher for local and distant recurrence (80% and 75%), whereas specificity was overall high (≥ 95%). Combining all recurrence categories irrespective of localization improved sensitivity to 90% with a specificity of 91%. In 87% of women, the date of first recurrence according to medical records fell within ± 90 days of the date recorded in the registry.

Conclusions: While the quality of data in the regional Breast Cancer Quality Registry was generally high, data accuracy on recurrences was lower. The overall precision of identifying any recurrence, irrespective of localization, was high. However, the accuracy of classification of recurrences (local, regional or distant) was lower, with evidence of underreporting for each of the recurrence categories. Given the importance of recurrence-related outcomes in the assessment of quality of care, efforts should be made to improve the reporting of recurrences.

Keywords: Breast cancer; Data accuracy; Follow-up studies; Quality registry; Validation.

MeSH terms

Breast Neoplasms* / diagnosis
Breast Neoplasms* / epidemiology
Breast Neoplasms* / therapy
Data Accuracy
Female
Humans
Neoplasm Recurrence, Local / epidemiology
Neoplasm Recurrence, Local / pathology
Registries
Sensitivity and Specificity
Sweden / epidemiology