Younger cancer patients at particularly increased risk of mortality from COVID-19

In a recent preprint study posted to the medRxiv* preprint server, researchers conducted a systematic review and meta-analysis to determine the impact and risk of severe acute respiratory syndrome-associated coronavirus 2 (SARS-CoV-2) in cancer patients based on age, tumor type, and therapy.

Study: A comprehensive systematic review and meta-analysis of the global data involving 61,532 cancer patients with SARS-CoV-2 infection. Image Credit: PongMoji/Shutterstock

SARS-CoV-2-associated mortality in cancer patients

There is an increased risk of respiratory viral infections in cancer patients due to the immunosuppression resulting from either the underlying illness or the pharmacotherapy. From previous studies on influenza virus and rhinoviruses infection in cancer patients, it is clear that there is an increased risk of mortality in cancer patients associated with these infections.

There was a global effort to understand the impact and outcomes of coronavirus disease 2019 (COVID-19) on cancer patients after the emergence of the SARS-CoV-2 pandemic. Previous studies have shown that cancer patients were found to be associated with an increased risk of severe COVID-19 infection and COVID-19-related deaths. However, these studies have numerous limitations such as a lack of effective control groups and variation in study designs and results.

The study

The present systematic review and meta-analysis were conducted to identify the impact of SARS-CoV-2 in cancer patients based on tumor type, age, and treatment, and any novel risk factors for COVID-19 in cancer patients. The participants were recruited from across five continents and 28 countries including the United Kingdom (UK), China, the United States (US), France, and Italy.

A systematic review of English articles about SARS-CoV-2 in more than 10 cancer patients published in Web of Science, PubMed, and Scopus till June 14, 2021, was performed as per the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. The references of the published articles were also reviewed to avoid duplication of the data. Subsequently, a meta-analysis was conducted by the random-effects model.

The inclusion criteria were full-text English articles on cohort or case-control studies with or without a non-cancer COVID-19 control group, and studies with either the presentation, incidence, outcome, or management of COVID-19 in cancer patients. The abstracts or conference papers, preprints, articles where the full text could not be extracted, studies with less than 10 participants, and animal studies were excluded from the study.

The risk of cancer patients for poor outcome in COVID-19 infection compared with those without the malignancy was determined by the meta-analysis based on the factors such as tumor subtype, patient demographics, and cancer treatments.

Results

There were a total of 61,532 cancer patients from the 81 studies included in the review. However, among the 81 studies, only 10 included both cancer patients and non-cancer patients with COVID-19. The number of cancer patients in the 81 studies varied from 11 to 38,614. The common comorbid conditions identified are pulmonary disease, hypertension, diabetes mellitus, and cardiovascular disease. Among the participants, 51% were hospitalized and the remaining were either unknown or outpatients.

The most common presenting symptoms of COVID-19 were cough, dyspnea, fever, fatigue, myalgia, and diarrhea. The duration between onset of COVID-19 symptoms and hospitalization varied from 1-40 days.

The risk of COVID-19-associated mortality in cancer patients compared to the non-cancer group reduced with age and was not significantly related to gender. The hematological malignancies cases accounted for 22.1% of all cancer cases reported and the relative risk (RR) of hematological malignancies with the non-cancer group was 1.81. Increased risk of mortality was seen in the lung, hematological, and genitourinary cancers; however, the mortality risk was the lowest in gynecological and breast cancers.

Cancer patients receiving endocrine therapy had the lowest overall pooled mortality risk (11%), whereas those who received chemotherapy had the highest overall pooled mortality risk (30%).

Conclusion

According to the authors, this is the largest review and meta-analysis of COVID-19 in malignancy patients based on the cancer types and treatments. The study reports that the COVID-19-associated mortality risk in cancer patients was higher in younger patients compared to the age-matched non-cancer cohorts. Therefore, younger cancer patients must be classified as a high-risk COVID-19 population.

Previous studies reported male gender as a risk factor for COVID-19-associated mortality in cancer patients, whereas this study states that the COVID-19 mortality risk in cancer patients is not related to gender. The outcomes varied based on the cancer types and therapy.

The age, gender, and comorbidity-controlled comparisons between cancer and non-cancer cohorts can be derived from ongoing studies like Clinical Characterization Protocol cancer UK (CCP-cancer-UK). The data from CCP-cancer-UK will also help identify the true risk of different tumor types and therapies possessed towards patient-level factors.

Future studies are essential to determine the impact of COVID-19 prevention and treatment measures between cancer and non-cancer patients. Similarly, individual patient-level meta-analyses on cancer patients are required to maximize the knowledge and to equip the cancer community against any future pandemics.

*Important notice

medRxiv publishes preliminary scientific reports that are not peer-reviewed and, therefore, should not be regarded as conclusive, guide clinical practice/health-related behavior, or treated as established information

Written by

Susha Cheriyedath

Susha has a Bachelor of Science (B.Sc.) degree in Chemistry and Master of Science (M.Sc) degree in Biochemistry from the University of Calicut, India. She always had a keen interest in medical and health science. As part of her masters degree, she specialized in Biochemistry, with an emphasis on Microbiology, Physiology, Biotechnology, and Nutrition. In her spare time, she loves to cook up a storm in the kitchen with her super-messy baking experiments.