The Impact of the COVID-19 Pandemic on New Lung Cancer Diagnosis in Mureș County, Romania: A 5-Year Retrospective, Comprehensive Study

<i>Background and Objectives</i>: Lung cancer (LC) remains a significant global health issue with poor prognosis. The COVID-19 pandemic has caused delays in cancer patient management worldwide. However, its impact on the incidence of LCs in Romania has not yet been discussed. We aimed to evaluate the impact of lockdown restrictions during the COVID-19 pandemic on new LC diagnoses in a Romanian cohort and the potential associations between demographic characteristics and histological features. <i>Materials and Methods</i>: This retrospective study analyzed 750 patients with lung tumors diagnosed in the Pathology Department, Mureș County Clinical Hospital, Romania, between 2018 and 2022. The target population was divided in two cohorts: pre-COVID-19 (1 January 2018-15 March 2020) and COVID-19 (16 March 2020-31 December 2022). <i>Results</i>: The temporal trend of LC diagnosis followed a descending pattern over the study period, with a significant 72% reduction (<i>p</i> < 0.001) in the first year of the COVID-19 pandemic (2020 vs. 2019). In terms of histology, several subtypes displayed a notable reduction in the COVID-19 cohort compared to the pre-pandemic period: squamous carcinoma (SQC) (<i>p</i> < 0.001), adenocarcinoma (ADK) (<i>p</i> < 0.001), and lung metastases (<i>p</i> = 0.0008). On the other hand, cases of non-small-cell lung carcinomas not otherwise specified (NSCLCs NOS) experienced a significant increase in the pandemic years (<i>p</i> = 0.0406). SQC was the most frequent subtype of LC and was significantly more frequent in men (<i>p</i> < 0.001, RR = 1.3004, 95% CI [1.1786-1.4347]). Furthermore, a notable shift in the male-to-female ratio was observed between the two cohorts, caused by a larger decrease in the incidence of LC among men compared to females in the COVID-19 period (<i>p</i> = 0.0002; pre-COVID-19 M/F = 4/1 versus COVID-19 M/F = 2/1). <i>Conclusions</i>: COVID-19-related restrictions led to a significant drop in new LC diagnoses during the first year of the pandemic, which was followed by a slight upward trend in the subsequent years. Additionally, the sharp decline in the number of cases among men narrowed the gender gap in LC patients.