Low-Dose Radiation Therapy for COVID-19: A Systematic Review

The ongoing COVID-19 pandemic is of great concern for the whole world, and finding an effective treatment for the disease caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is, therefore, a global race. In particular, treatment options for elderly patients and patients with genetic risk factors with COVID-19-associated pneumonia are limited, and many patients die. Low-dose radiotherapy (LDRT) of lungs was used to treat pneumonia many decades ago. Since the first report on the potential efficacy of LDRT for COVID-19-associated pneumonia was published on 1 April, 2020, tens of papers have addressed the importance of this treatment. Moreover, the findings of less than 10 clinical trials conducted to date are now available. We performed a detailed search of PubMed/MEDLINE, Web of Science, Google Scholar, and Scopus and selected the nine most relevant articles. A review of these articles was conducted. The available data indicate that in oxygen-dependent elderly patients with COVID-19-associated pneumonia, whole-lung radiation at doses of 0.5–1.5 Gy can lead to accelerated recovery and progress in clinical status, encephalopathy, and radiographic consolidation without any detectable acute toxicity. Although data collected so far show that LDRT could be introduced as a treatment with promising efficacy, due to limitations such as lack of randomization in most studies, we need further large-scale randomized studies, especially for elderly patients who are at greater risk of mortality due to COVID-19. However, more preclinical work and clinical trials are needed before any clear conclusion can be made.