Systematic screening of COVID-19 disease based on chest CT and RT-PCR for cancer patients undergoing radiotherapy in a coronavirus French hotspot.

ABSTRACT Background Cancer patients are presumed to be more vulnerable to COVID-19. We evaluated a screening strategy combining chest computed-tomography (CT) and reverse transcription polymerase chain reaction (RT-PCR) for patients treated with radiotherapy (RT) in our cancer center located in a COVID-19 French hotspot during the first wave of the pandemic. Methods Chest CT images were proposed during the radiotherapy CT simulation. Images were reviewed by an expert radiologist according to the CO-RADS classification. Nasal swabs with RT PCR assay were initially proposed in case of suspicious imaging or clinical context and were eventually integrated into the systematic screening. A dedicated radiotherapy workflow was proposed for COVID-19 patients to limit the risk of contamination. Results From March 18, 2020 to May 1, 2020, 480 patients were screened by chest CT, with 313 patients having both chest CT and RT-PCR (65%). Cumulative incidence of COVID-19 was 5.4%, 95%CI [3.6, 7.8] (26 patients out of 480). Diagnosis of COVID-19 was made before RT for 22 patients (84.6%) and during RT for 4 patients (15.3%). Chest CT directly aided the diagnosis of 7 cases for whom the initial RT-PCR was negative or not feasible; out of a total of 480 patients (1.5%) and 517 chest CT acquisition. Four patients with COVID-19 at the time of the chest CT screening had a false negative CT. Sensitivity and specificity of chest CT screening in patients with both RT-PCR and chest CT testing were estimated to be 0.82, 95% CI [0.60, 0.95] and 0.98, 95% CI [0.96, 0.99] respectively.Adaptation of the radiotherapy treatment was made for all the patients with seven postponed treatments (median=5 days, IQR [1.5, 14.8]). Conclusion The benefit of systematic use of chest CT screening during CT simulation for patients undergoing radiotherapy during the COVID-19 pandemic seemed limited.