Impact of the COVID-19 Pandemic on Lung Cancer Epidemiology in Portugal: updated disease burden and survival profiles

Abstract

Background: The COVID-19 pandemic impacted healthcare services worldwide, delaying the processes of referral, diagnosis, staging and treatment. Consequently, oncologic patients are vulnerable to increased morbimortality. The standardised use of thoracic computed tomography (CT) as a diagnostic tool for both lung cancer (LC) and COVID infection led to an increase in incidental LC diagnoses during this period. Objective: To determine the impact of the COVID-19 pandemic on LC patients' management and outcomes. Methods: Retrospective cohort study from a tertiary centre including all patients diagnosed with LC in 2019 (pre-pandemic), 2020 (pandemic) and 2023 (post-pandemic). Total LC diagnoses and proportion of each stage were compared across the 3 years of study, as well as other metrics of overall disease burden. Results: 914 patients were diagnosed with LC. During the pandemic, there was an absolute decrease in total LC diagnoses (187 vs. 259 in the same period of 2019; p<0.001) and the proportion of metastatic LC increased from 42.8% to 57.7% (p<0.001). Urgent referrals registered a significant increase from 2019 to 2020 (31.2% versus 45.7%; p<0.001). ECOG-PS at diagnosis was significantly worse in 2020 (17.9% of patients with an ECOG-PS 2-4 in 2019 versus 27.4% in 2020; p=0.007). Compared to the pre-pandemic period, in 2023, the number of referrals after an incidental chest CT finding significantly increased (32.6% versus 53.5%; p<0.001) with an increase of ~8% in elective referrals (p=0.031) and in limited-stage disease diagnoses from 2019 to 2023 (25.9% versus 39.1%; p<0.001). Between the pre- and post-pandemic periods, the diagnosis of limited-stage LC (IIB or lower) was significantly more frequent (25.9% versus 39.1%; p<0.001. Even though 12-month survival rates did not differ significantly, patients diagnosed in 2020 displayed the lowest overall survival rates of the three groups. Conclusion: The pandemic caused more advanced LC staging and higher rates of emergent referrals, leading to worse survival. However, the post-pandemic use of lung CT increased the diagnosis of localized disease, resulting in increased survival rates.