Patterns of Radiation Therapy During the COVID-19 Pandemic: Results from the Multicenter, Cross-Sectoral Registry of the German National Pandemic Cohort Network (NAPKON)

Background: Cancer patients receiving or having received radiotherapy (RT) represent a clinically vulnerable group during the COVID-19 pandemic. However, systematic data on their clinical course, comorbidities, and vaccination status are limited. The German National Pandemic Cohort Network (NAPKON), established to systematically collect comprehensive clinical data on COVID-19 patients nationwide, provides a unique opportunity to address this gap. This study aimed to describe radiation therapy patterns and COVID-19-related clinical characteristics among patients documented within the NAPKON Cross-Sectoral Platform (SUEP). Methods: This multicenter, descriptive analysis was conducted within the framework of the German National Pandemic Cohort Network (NAPKON). All patients with documented RT and confirmed SARS-CoV-2 infection were identified in the SUEP database. RT was classified relative to the documented infection date as occurring before, during, or after infection. Demographic, clinical, laboratory, imaging, and vaccination data were extracted and analyzed descriptively. Due to the small sample size, no correlation or multivariable analyses were performed. Results: A total of n = 90 patients were included in the analysis. The median age was 65 years (range 22–90), and 56% were male. Most patients (93%) received one course of RT, most frequently targeting specific organ systems (54%), while total body irradiation was performed in 4%. The median radiation dose was 45 Gy (IQR 30–60). Among 68 patients with evaluable timing information, RT had been administered before infection in 53 patients (77.9%), during infection in 3 patients (4.4%), and after infection in 12 patients (17.6%). At the time of SARS-CoV-2 detection, 76% of patients experienced a phase without complications, 19% a phase with complications, and 2% a critical phase. The majority of vaccinated individuals had received Comirnaty (BioNTech/Pfizer; 80%). COVID-19-typical findings were identified in 18% of chest X-rays and 27% of CT scans. Clinical and laboratory characteristics showed no substantial differences by hospital length of stay. Conclusions: Patients with documented RT and SARS-CoV-2 infection in the NAPKON registry predominantly experienced mild or moderate COVID-19 courses and showed a relatively high vaccination uptake. However, due to the descriptive study design and the absence of a control group, these findings should not be interpreted as being attributable to RT itself but rather as a characterization of this registry cohort. Importantly, the cohort mainly comprised patients with a history of RT before SARS-CoV-2 infection, whereas only a small minority received RT during infection. Although the analysis was descriptive and limited by missing data, it demonstrates the feasibility and scientific value of integrating oncologic subcohorts within national pandemic research networks. Continued longitudinal analyses will be essential to further characterize outcomes of patients with cancer and RT in future pandemics.