A new systematic review and meta-analysis finds that unvaccinated cancer patients who contracted COVID-19 last year, were more than two times more likely – than people without cancer – to develop a case of COVID-19 so severe it required hospitalization in an intensive care unit.
“Our study provides the most precise measure to date of the effect of COVID-19 in cancer patients,” wrote researchers who were led by Paolo Boffetta, MD, MPH, a specialist in population science with the Stony Brook Cancer Center in New York.
Dr. Boffetta and colleagues also found that patients with hematologic neoplasms had a higher mortality rate from COVID-19 comparable to that of all cancers combined.
Cancer patients have long been considered to be among those patients who are at high risk of developing COVID-19, and if they contract the disease, they are at high risk of having poor outcomes. Other high-risk patients include those with hypertension, diabetes, chronic kidney disease, or COPD, or the elderly. But how high the risk of developing severe COVID-19 disease is for cancer patients hasn’t yet been documented on a wide scale.
The study, which was made available as a preprint on medRxiv on Oct. 23, is based on an analysis of COVID-19 cases that were documented in 35 reviews, meta-analyses, case reports, and studies indexed in PubMed from authors in North America, Europe, and Asia.
In this study, the pooled odds ratio for mortality for all patients with any cancer was 2.32 (95% confidence interval, 1.82-2.94; 24 studies). For ICU admission, the odds ratio was 2.39 (95% CI, 1.90-3.02; I2 0.0%; 5 studies). And, for disease severity or hospitalization, it was 2.08 (95% CI, 1.60-2.72; I2 92.1%; 15 studies). The pooled mortality odds ratio for hematologic neoplasms was 2.14 (95% CI, 1.87-2.44; I2 20.8%; 8 studies).
Their findings, which have not yet been peer reviewed, confirmed the results of a similar analysis from China published as a preprint in May 2020. The analysis included 181,323 patients (23,736 cancer patients) from 26 studies reported an odds ratio of 2.54 (95% CI, 1.47-4.42). “Cancer patients with COVID-19 have an increased likelihood of death compared to non-cancer COVID-19 patients,” Venkatesulu et al. wrote. And a systematic review and meta-analysis of five studies of 2,619 patients published in October 2020 in Medicine also found a significantly higher risk of death from COVID-19 among cancer patients (odds ratio, 2.63; 95% confidence interval, 1.14-6.06; P = .023; I2 = 26.4%).
Fakih et al., writing in the journal Hematology/Oncology and Stem Cell Therapy conducted a meta-analysis early last year finding a threefold increase for admission to the intensive care unit, an almost fourfold increase for a severe SARS-CoV-2 infection, and a fivefold increase for being intubated.
The three studies show that mortality rates were higher early in the pandemic “when diagnosis and treatment for SARS-CoV-2 might have been delayed, resulting in higher death rate,” Boffetta et al. wrote, adding that their analysis showed only a twofold increase most likely because it was a year-long analysis.
“Future studies will be able to better analyze this association for the different subtypes of cancer. Furthermore, they will eventually be able to evaluate whether the difference among vaccinated population is reduced,” Boffetta et al. wrote.
The authors noted several limitations for the study, including the fact that many of the studies included in the analysis did not include sex, age, comorbidities, and therapy. Nor were the authors able to analyze specific cancers other than hematologic neoplasms.
The authors declared no conflicts of interest.