Cost-effectiveness of diagnostic tests during follow-up in lung cancer patients: an evidence-based study

Background: Many patients with non-metastatic non-small cell lung cancer (NSCLC) are cured by surgery but part of them develop recurrence. Strategies are needed to identify these relapses. Currently, there is no consensus on the follow-up schedule after curative resection for patients with NSCLC. The objective of this study is to analyze the diagnostic capacity of the tests performed during follow-up after surgery. Methods: We retrospectively reviewed 392 patients with stage I-IIIA NSCLC who underwent surgery. Data were collected from patients diagnosed between January 1st, 2010 and December 31st, 2020. Demographic and clinical data were analyzed, as well as the tests performed during their follow-up. We identified as relevant in the diagnosis of relapses those tests that prompted further investigation and change of treatment. Results: The number of tests matches those included in clinical practice guidelines. A total of 2,049 clinical follow-up consultations were performed, of which 2,004 were scheduled (0.59% informative). A total of 1,796 blood tests were performed, of which 1,756 were scheduled (0.17% informative). A total of 1,940 chest computer tomography (CT) scans were performed, of which 1,905 were scheduled and 128 were informative (6.7%). A total of 144 positron emission tomography (PET)-CT scans were performed, 132 of which were scheduled, of which 64 (48%) were informative. In all cases, the tests performed by unscheduled request exceeded the informative result of the scheduled ones several fold. Conclusions: Most of the scheduled follow-up consultations were not relevant for the patients' management, and only body CT scan exceeded the threshold of 5% profitability, without reaching 10% even in stage IIIA. The profitability of the tests increased when performed in unscheduled visits. New follow-up strategies based on scientific evidence must be defined and follow-up schemes should be tailored focused on agile attention of the unscheduled demand.