Clinical Epidemiology (Mar 2023)
A Validated Register-Based Algorithm to Identify Patients Diagnosed with Recurrence of Surgically Treated Stage I Lung Cancer in Denmark
Abstract
Linda Aagaard Rasmussen,1 Niels Lyhne Christensen,2 Anne Winther-Larsen,3 Susanne Oksbjerg Dalton,4,5 Line Flytkjær Virgilsen,1 Henry Jensen,1 Peter Vedsted1 1Research Unit for General Practice, Aarhus, Denmark; 2Department of Pulmonary Medicine and Allergy, Aarhus University Hospital, Aarhus, Denmark; 3Department of Clinical Biochemistry, Aarhus University Hospital, Aarhus, Denmark; 4Survivorship and Inequality in Cancer, Danish Cancer Society Research Center, Copenhagen, Denmark; 5Department of Clinical Oncology & Palliative Care, Zealand University Hospital, Næstved, DenmarkCorrespondence: Linda Aagaard Rasmussen, Research Unit for General Practice, Bartholins Allé 2, Aarhus C, 8000, Denmark, Tel +45 8716 8365, Email [email protected]: Recurrence of cancer is not routinely registered in Danish national health registers. This study aimed to develop and validate a register-based algorithm to identify patients diagnosed with recurrent lung cancer and to estimate the accuracy of the identified diagnosis date.Material and Methods: Patients with early-stage lung cancer treated with surgery were included in the study. Recurrence indicators were diagnosis and procedure codes recorded in the Danish National Patient Register and pathology results recorded in the Danish National Pathology Register. Information from CT scans and medical records served as the gold standard to assess the accuracy of the algorithm.Results: The final population consisted of 217 patients; 72 (33%) had recurrence according to the gold standard. The median follow-up time since primary lung cancer diagnosis was 29 months (interquartile interval: 18– 46). The algorithm for identifying a recurrence reached a sensitivity of 83.3% (95% CI: 72.7– 91.1), a specificity of 93.8% (95% CI: 88.5– 97.1), and a positive predictive value of 87.0% (95% CI: 76.7– 93.9). The algorithm identified 70% of the recurrences within 60 days of the recurrence date registered by the gold standard method. The positive predictive value of the algorithm decreased to 70% when the algorithm was simulated in a population with a recurrence rate of 15%.Conclusion: The proposed algorithm demonstrated good performance in a population with 33% recurrences over a median of 29 months. It can be used to identify patients diagnosed with recurrent lung cancer, and it may be a valuable tool for future research in this field. However, a lower positive predictive value is seen when applying the algorithm in populations with low recurrence rates.Keywords: lung neoplasms, recurrence, algorithms, validation study, registries, Denmark
