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

Background: The coronavirus disease (COVID-19) pandemic has caused 180,000 confirmed cases in France with more than 28, 000 deaths as of May 19. A large part of COVID-19 patients seem asymptomatic and cancer patients may be more vulnerable. We evaluated a screening strategy combining chest computed tomography (CT) and PCR for patients treated with radiotherapy (RT). Methods: A screening strategy was organized from March 18, in our RT department. An inspiratory breath hold chest acquisition was proposed during the CT simulation for RT. Images was reviewed by a radiologist according to the CO-RADS classification. A nasal swab with a polymerase chain reaction (PCR) assay was proposed by the radiation oncologist in case of evocative imaging or clinical context. For patients who were already undergoing RT at this time, a PCR was proposed in case of evocative symptoms and before concomitant chemotherapy. Results: From March 18 to May 1, 2020, 507 CT simulation were performed for 449 patients, including 445 chest acquisition. 237 of the chest CT (53%) showed lung abnormalities, of which 34 (8%) were COVID-19 compatible (CO-RADS ≥ 3). 102 patients were tested by PCR after the chest CT. 24 of the 449 (5.3%) patients were considered as COVID-19 patients: 19 had positive PCR, and five were considered positive on the basis of imaging despite PCR-negative PCR. Four of the patients (17%) were diagnosed during RT: 3 on routine screening before chemoradiotherapy, and one on symptoms. Four patients needed several PCR for the diagnosis of COVID-19 with six confirmed false negative PCR (Sensitivity (Se)= 76 % (19/25)). Three PCR positive patients had no evocative lung images (Se = 84%). During this period, an additional 169 patients whose CT simulation was prior to March 18, were also undergoing RT. Among them, six patients (3.6%) were diagnosed with COVID-19 by PCR during RT, performed for symptoms in 4 cases and on screening for the other 2. Of the 30 COVID-19 patients, only 8 (27%) had symptoms at the time of diagnosis. Twelve patients (40%) reported no symptoms and benefited from screening. Conclusions: This study confirms the high proportion of asymptomatic patients with COVID-19 and suggests the value of screening by CT and PCR during COVID-19 pandemics. Legal entity responsible for the study: The authors. Funding: Has not received any funding. Disclosure: R. Sun: Travel/Accommodation/Expenses: AstraZeneca. E. Deutsch: Advisory/Consultancy: Roche, BMS, Boehringer, Astrazeneca, Lilly Amgen and Merck-Serono. All other authors have declared no conflicts of interest.