Section 4: Discussion (from DOI: 10.1016/j.adro.2020.04.015)
From publication: "Need for Caution in the Diagnosis of Radiation Pneumonitis in the COVID-19 Pandemic" published as Adv Radiat Oncol; 2020 May 05. DOI: https://doi.org/10.1016/j.adro.2020.04.015
Section 4: Discussion
This report illustrates the overlapping symptoms and imaging features of RP and COVID-19, and the need for diagnostic caution in the management of these findings.
COVID-19 and RP are both characterized by similar symptoms including cough, dyspnea and fever. Ground-glass opacities and consolidations are characteristic Chest CT radiographic findings of both pathologies, but data indicate differences in the distribution of these features between these pathologies. Chest CT findings of COVID-19 are present in approximately 80% of symptomatic patients. Early reports indicate up to 85% of patients have imaging findings in more than one lobe and 90% of patients have bilateral chest CT findings. This contrasts to RP, where opacities are classically noted mostly within the radiation field.
Currently available diagnostic testing for COVID-19 commonly identify viral RNA in nasopharyngeal and/or oropharyngeal samples through nucleic acid amplification. These tests, while mostly specific, have a clinical sensitivity that is yet to be fully determined. Early reports indicate a significant false negative rate and the potential for higher sensitivity using lower respiratory track samples. Therefore, clinical judgement and continuous reassessment of pulmonary symptoms remains critical in patients who test negative for COVID-19.
The treatment of RP and COVID-19 are substantially different. The treatment for symptomatic RP includes a high-dose corticosteroid taper. However, there is data-driven concern that corticosteroids can worsen COVID-19-associated lung injury, with prior studies finding corticosteroid therapy to delay clearance of Middle East Respiratory Syndrome (MERS) coronavirus and Severe Acute Respiratory Syndrome (SARS) coronavirus from the respiratory track and plasma. This may have been the case in the first two patients presented, where the use of empiric high-dose corticosteroids may have contributed to their clinical deterioration.
Review of imaging findings to characterize the nature and distribution of pulmonary changes in relation to the radiation treatment field.
Prioritization of COVID-19 testing prior to starting high-dose corticosteroids to prevent potential exacerbation of COVID-19 in these high-risk patients.
Close monitoring of pulmonary symptoms, particularly among patients who initially test negative for COVID-19, to assess for superimposed conditions including COVID-19.
We, therefore, recommend these steps in the managements of patients with a differential diagnosis that includes RP (Figure 2 ):
As the pandemic continues, this diagnostic dilemma will become increasingly present for providers. Given that cancer patients, particularly those with lung cancers, are at increased risk for severe events, close monitoring of these patients and the impact of their oncologic therapies on COVID-19 outcomes are warranted.
