Covert Covid-19: CBCT Lung Changes in An Asymptomatic Patient Receiving Radiotherapy

Youssef, Irini; Donahue, Bernadine; Flyer, Mark; Thompson, Sharon; Huang, Alice; Gallant, Fleure

INTRODUCTION: COVID-19 profoundly impacted the United States, with New York City (NYC) rapidly becoming the epicenter of the disease. Cancer patients represent a vulnerable population in this pandemic, with data suggesting a higher risk for severe events and unfavorable outcomes. Timely identification of COVID-19 in cancer patients has been thwarted by the lack of outpatient testing for SARS-CoV-2. Chest computed tomography (CT) plays a major role in the identification of COVID-19 pneumonia, with radiologic hallmarks including bilateral, peripheral ground-glass opacities (GGOs) and consolidation. Cancer patients undergoing radiotherapy (RT) commonly have daily cone beam computed tomography (CBCT) obtained for image-guided radiotherapy (IGRT), and such imaging frequently includes the chest. METHODS: We retrospectively reviewed the CBCTs of an initially asymptomatic patient undergoing IGRT for breast cancer, who developed COVID-19 symptoms during the second week of RT. Lung windows of daily CBCTs were reviewed with Diagnostic Radiology to survey for changes consistent with COVID-19. Diagnostic CTs obtained at the time of recovery were obtained and compared with the CBCTs. RESULTS: Five consecutive CBCTs were retrospectively reviewed. Bilateral, peripheral GGOs were noted on the 4(th) and 5(th) CBCTs in the two days prior to symptom onset. CBCT on the day of RT resumption demonstrated substantial worsening of the GGO compared with those obtained during the asymptomatic phase. Diagnostic CTs demonstrated bilateral, peripheral GGOs and mediastinal lymphadenopathy, findings suggesting COVID-19 pneumonitis. Repeat diagnostic CT three days later showed improved pulmonary findings and the patient resumed RT without incident. CONCLUSION: Familiarity with typical CT changes of COVID-19 pneumonitis may allow for early detection in cancer patients undergoing CBCT for RT treatment. Prompt review of the lung windows is recommended in order to identify such changes, with the hope that pre-symptomatic diagnosis leads to expedited patient management, improved outcomes, and a reduction of inadvertent COVID-19 dissemination.