Narrowing the therapeutic window?-A case-control study on the influence of the COVID-19 pandemic on the primary UICC stage of NSCLC.

Background: General clinical perception suggests a decline in the diagnosis and treatment of lung cancer during the SARS-CoV-2 pandemic. Early diagnosis of non-small cell lung cancer (NSCLC) is crucial in therapeutic regimes as early stages are potentially curable by operation alone or with combined therapy. Pandemic-triggered overload of the healthcare system may have prolonged the diagnosis of NSCLC, possibly leading to higher tumor stages at first diagnosis. This study aims to identify how COVID-19 affected the distribution of the Union for International Cancer Control (UICC) stage in NSCLC at first diagnosis. Methods: A retrospective case-control study was conducted, including all patients receiving their first diagnosis of NSCLC in the regions of Leipzig and Mecklenburg-Vorpommern (MV) between January 2019 and March 2021. Patient data were retrieved from the clinical cancer registries of the city of Leipzig and the federal state of MV. Ethical approval for this retrospective evaluation of archived, anonymized patient data was waived by the Scientific Ethical Committee at the Medical Faculty, Leipzig University. Three investigation periods were defined to study the effects of high incidences of SARS-COV-2: the curfew period as an enacted security measure, the period of high incidence rates and the period of the aftermath of high incidences. Differences in the UICC stages between these pandemic periods were studied by Mann-Whitney-U-Test. Pearson's correlation was calculated to examine changes in operability. Results: The number of patients diagnosed with NSCLC dropped substantially during investigation periods. There was a significant difference in the UICC status in the aftermath of high incidences and imposed security measures in Leipzig (P=0.016). N-status differed significantly in the aftermath of high incidences and imposed security measures (P=0.022) with a decrease of N0- and an increase of N3-status, respectively, while N1- and N2-status remained relatively unaffected. No pandemic phase showed a significant difference in operability. Conclusions: The pandemic led to a delay in the diagnosis of NSCLC in the two examined regions. This resulted in higher UICC stages upon diagnosis. However, no increase in inoperable stages was shown. It remains to be seen, how this will affect the overall prognosis of the involved patients.