1675MO - 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.

Clinical trial identification

Editorial acknowledgement

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.