Disease Severity in Cancer Patients Infected With SARS-COV-2: An Ambiguous Issue.

Abstract

To the Editor: Patients with cancer are considered more susceptible to SARS-CoV-2 infection. One of the serious complications of COVID-19 is hyperactivation of the immune system, which induces an uncontrolled production of cytokines that poses a high mortality. Although a weakened immune system may be harmful in the initial phase of COVID-19, the phase that the immune response is necessary to inhibit viral replication, in immunocompromised patients, an attenuated inflammatory response may not be associated with development of severe COVID-19 and also cytokine storm, due to suppression of some pathway of cellular or humeral responses1; hence, immunosuppression might have a beneficial effect on the cytokine release storm phase of COVID-19 in these groups of patients. On the other hand, several immunosuppressive drugs and chemotherapeutic agents used in these patients that have direct inhibitory effects on SARS-CoV-2 replication in vitro or induce potentially increased vulnerability to this virus are known.2 With the onset of the coronavirus pandemic, studies on the relationship between viral load and disease severity have been performed. It is unknown whether viral load really affects the disease severity or not. Some studies showed that viral load has important prognostic implications and could therefore help identify patients who are at highest risk for adverse outcomes. In addition, it was shown that, compared with patients with mild disease, those with severe disease showed higher viral load and a later shedding peak.3,4 On the other hand, it has been shown that viral load based on cycle threshold values seem to be different in solid tumors versus hematologic malignancies in patients undergoing chemotherapy. One study showed that patients with hematologic malignancies had higher viral loads than did patients with solid tumors or patients without cancer. This finding may be from the underlying immunodeficiencies and therapies administered that confer a decreased ability to inhibit the proliferation of a virus without a statistically significant increase in mortality among patients with hematologic malignancies versus patients with solid tumors or patients without cancer.5 In another study, Ju et al6 reported 2 cancer patients, 1 with critical type and 1 asymptomatic carrier, who were undergoing or just completed chemotherapy treatment, respectively, with favorable outcomes after being infected with COVID-19. The authors reported a low viral load level in both patients despite receiving chemotherapy. Whether cancer itself is an independent risk factor for severe COVID-19 remains to be clarified. What seems to be important is not a single factor, but the host immune system, viral load, immunosuppressive drugs' effects on virus replication and phase of disease, and chemotherapy may play a role that determines the severity of the disease. More studies are needed to clarify this association. Masoud Mardani, MDAtousa Hakamifard, MD Infectious Diseases and Tropical Medicine Research Center Shahid Beheshti University of Medical Sciences Tehran, Iran [email protected]