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

Abstract

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.

Effect of Low-Dose Radiotherapy on the Circulating Levels of Paraoxonase-1-Related Variables and Markers of Inflammation in Patients with COVID-19 Pneumonia

“…These results agree with those published previously. Several groups, including our own, have shown that whole-lung radiation at doses of 0.5–1.5 Gy can accelerate the recovery in clinical and radiographic status without acute toxicity [ 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ]. The appearance of new variants and the high degree of vaccination in most high-income countries has changed the scenario since 2020, towards a less severe disease and therefore, the usefulness of LDRT may be lower in the future than in these recent years.…”

Revisiting the Paradox of Smoking: Radioactivity in Tobacco Smoke or Suppressing the SARS-CoV-2 Receptor, Angiotensin-Converting Enzyme 2, via Aryl-Hydrocarbon Receptor Signal?

“… 39 - 41 Therefore, the anti-inflammatory effects of localized radiation via alpha particles as well as the effect of low doses of radiation on reducing the risk of thrombosis are possibly involved in the lower number of hospitalized smokers than expected. 23 , 42 , 43 …”

Impact of X-radiation in the management of COVID-19 disease

“…The sudden outbreak of SARS-CoV-2 infections results in COVID-19 disease, which is associated with compromised immunological defense and lung damage[ 38 ]. Therefore, the COVID-19 patients were isolated/quarantined and provided with medication and supplements to boost their immune mechanism to overcome the disease[ 39 ]. In addition to the boosters to immune mechanisms, several therapy strategies were tested to prevent viral entry, inhibition of virus replication, immunomodulatory agents, immunoglobulin therapy, vaccines, and potential control measures[ 28 ].…”

“…One of those therapy strategies is the use of LDRT for COVID-19-infected patients because it has been proven to cure pneumonia in the early 20 th century[ 40 ]. The treatment with low-dose X-rays complements other treatment modalities and has a profound role in minimizing COVID-19 infection severity[ 39 ]. Low dose comprises doses below 100 mGy as defined by UNSCEAR and has the characteristics such as accelerated immune senescence, altered immune fitness, a shift in peripheral lymphocyte, balance in favor of B-cells, and pro-inflammatory responses[ 39 ].…”

“…The treatment with low-dose X-rays complements other treatment modalities and has a profound role in minimizing COVID-19 infection severity[ 39 ]. Low dose comprises doses below 100 mGy as defined by UNSCEAR and has the characteristics such as accelerated immune senescence, altered immune fitness, a shift in peripheral lymphocyte, balance in favor of B-cells, and pro-inflammatory responses[ 39 ]. The first attempt on the use of LDRT for COVID-19-related pneumonia was made by Italian and American scientists for which the patients received a single dose of either 0.10, 0.18 or 0.25 Gy[ 38 ].…”