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| LETTER TO EDITOR |
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| Year : 2020 | Volume
: 3
| Issue : 4 | Page : 830-832 |
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Low-dose radiotherapy for COVID-19 pneumonia: A possible low-cost treatment option for immunomodulation
Namrata Das, Kannan Periasamy
Department of Radiotherapy and Oncology, PGIMER, Chandigarh, India
| Date of Submission | 29-Sep-2020 |
| Date of Decision | 10-Oct-2020 |
| Date of Acceptance | 16-Oct-2020 |
| Date of Web Publication | 25-Dec-2020 |
Correspondence Address:
Kannan Periasamy
Department of Radiotherapy and Oncology, Regional Cancer Centre, PGIMER, Chandigarh - 160 012
India
 Source of Support: None, Conflict of Interest: None
DOI: 10.4103/CRST.CRST_299_20
How to cite this article:
Das N, Periasamy K. Low-dose radiotherapy for COVID-19 pneumonia: A possible low-cost treatment option for immunomodulation. Cancer Res Stat Treat 2020;3:830-2 |
How to cite this URL:
Das N, Periasamy K. Low-dose radiotherapy for COVID-19 pneumonia: A possible low-cost treatment option for immunomodulation. Cancer Res Stat Treat [serial online] 2020 [cited 2021 Jan 20];3:830-2. Available from: https://www.crstonline.com/text.asp?2020/3/4/830/304973 |
The coronavirus disease 2019 (COVID-19) pandemic caused by infection with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continues to spread and has caused more than 1 million deaths worldwide as of October 2020.[1],[2] Mortality rates remain well above 30% in the vulnerable group of patients despite intensive support. This has triggered research in the development of new therapeutic strategies.[3] The number of registered interventional clinical studies stood at 1253 in June 2020, out of which a few studies in India, Spain, Italy, and the United States of America are investigating the role of low-dose radiation as a means of combating COVID-19 pneumonia [Table 1].[4] Understanding the history and mechanism of action of low-dose radiation may help explain the resurgence of interest in this low-cost treatment modality. | Table 1: Registered clinical trials that aim to target COVID-19 pneumonia with low dose radiotherapy[2]
Click here to view |
Low-dose radiation is defined as the delivery of doses below 1 Gy, usually in a single session. Low-dose radiation has been shown to possess immunomodulatory properties in both in-vivo and in-vitro studies. Moreover, a polarization of macrophages to the anti-inflammatory M2 phenotype has been associated with doses of radiation below 1 Gy. Thus, a clinically protective response is observed by decreasing the inflammatory milieu. Care must be taken to avoid irradiation during convalescence where the inflammatory response is helping the recovery of the patient.[5],[6] Historically, high response rates have been seen in over 75% of the patients for benign inflammatory diseases such as pneumonia, arthritis, gas gangrene, etc. Low-dose radiotherapy continues to be used in many European centers. Another pertinent point is the necessity of initiating radiation as soon as the signs of inflammation appear. Initiating treatment within hours can lead to cure rates of over 90%, which subsequently decrease with time.[7.8]
A dose of 0.3–0.5 Gy has been considered by experts as an acceptable dose for COVID-19-associated acute respiratory distress syndrome (ARDS), since early reactions are unlikely with such a low dose while maintaining the anti-inflammatory efficacy.[9],[10] There is also concern about the increased risk of radiation-induced malignancy, but considering the grave prognosis of those being treated, the benefit in all likelihood outweighs the risk.[11],[12] Preliminary reports from two pilot studies have shown clinical response rates of 80% with low-dose radiotherapy for COVID-19 pneumonia.[13],[14] It is a simple, single-session, cost-effective therapeutic option that added to steroids and can be provided as an alternative when other investigational drugs like tocilizumab are not available.[15]
Low-dose radiotherapy holds promise in modulating the unregulated immune response that leads to fatal outcomes in progressive COVID-19 pneumonia. However, clinical trials have to tread with caution and learn from history in choosing the right patients and instituting treatment in the golden window of early progression of symptoms where response is most expected.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
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| 11. | Algara M, Arenas M, Marin J, Vallverdu I, Fernandez-Letón P, Villar J, et al. Low dose anti-inflammatory radiotherapy for the treatment of pneumonia by COVID-19: A proposal for a multi-centric prospective trial. Clin Transl Radiat Oncol 2020;24:29-33. |
| 12. | Kirsch DG, Diehn M, Cucinotta FA, Weichselbaum R. Lack of supporting data make the risks of a clinical trial of radiation therapy as a treatment for COVID-19 pneumonia unacceptable. Radiother Oncol 2020;147:217-20. |
| 13. | Hess CB, Buchwald ZS, Stokes W, Nasti TH, Switchenko JM, Weinberg BD, et al. Low-dose whole-lung radiation for COVID-19 pneumonia: Planned day 7 interim analysis of a registered clinical trial. Cancer 2020;126: 5109-5113. |
| 14. | Ameri A, Rahnama N, Bozorgmehr R, Mokhtari M, Farahbakhsh M, Nabavi M, et al. Low-dose whole-lung irradiation for COVID-19 pneumonia: Short course results. Int J Radiat Oncol Biol Phys 2020;108: 1134-1139. |
| 15. | Lara PC, Burgos J, Macias D. Low dose lung radiotherapy for COVID-19 pneumonia. The rationale for a cost-effective anti-inflammatory treatment. Clin Transl Radiat Oncol 2020;23:27-9. |
[Table 1]
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