Study: Cancer treatment not a major COVID-19 risk
BOSTON – People with cancer are far more likely to die from COVID-19 than the general population, though for the same basic reasons – because of their older age, male gender, smoking history and multiple health problems, according to a study published Thursday in The Lancet.
While COVID-19 has killed about 6% of Americans diagnosed with it, the study found 13% of cancer patients died within a month of catching the coronavirus that causes the disease.
But some of the factors researchers worried might increase patients’ risk of death – such as recent cancer treatment – turned out not to play a major role, the study found.
Launched as a result of Twitter conversations among cancer researchers in the U.S., Canada and Spain, the study was intended to better understand extra risks cancer patients may face, and to help guide treatment, said co-author Toni Choueiri, a genitourinary oncologist at the Dana-Farber Cancer Institute in Boston.
The research also highlights questions about how being immunocompromised, from cancer treatment or other causes, affects the risk of a serious infection or even death from COVID-19.
Pregnant women, people with autoimmune diseases, those with blood cancers and organ transplant recipients would be expected to be the most vulnerable to a lethal virus because of their reduced ability to fight off infection. Instead, some early studies suggest many fare OK when infected.
“They’re not sitting ducks and, in fact, they may do better” than people with typical immune systems, said Carl June, an immunologist and oncologist at the Perelman School of Medicine of the University of Pennsylvania.
It’s not yet clear why this is the case. In many people with the most serious reaction to COVID-19 infections, their immune systems go into overdrive, attacking organs, instead of the virus. Perhaps bodies with a reduced ability to fight disease don’t overreact in this way.
“It’s raised at least the hypothesis that there may be some protective effect of a modest degree of immunosuppression,” said George Daley, dean of Harvard Medical School.
This idea, along with the findings of the new study, mean cancer patients should worry more about missing their treatments than the possible dangers of catching COVID-19, said Antoni Ribas, a cancer doctor at the University of California, Los Angeles.
Their cancer, he said, poses a much greater threat to them than the virus does.
“Many cancer treatments do not weaken the immune system to a level that it could not fight the virus, so the notion that patients with cancer are all immunocompromised is troubling to me,” he wrote in an email. “In fact, many modern cancer treatments do not weaken the immune system at all, and some of them are immunotherapies that help fight cancer, and in mouse models, the same therapies also fight viral infections.”
People in the new study who had active cancer – about 40% of the total – seemed to fare worse than those whose cancer was in remission. But specific treatments such as surgery or a type of immune therapy called checkpoint inhibitors did not increase risk, said the co-author, Choueiri.
That should make patients feel better about getting whatever treatment their oncologist recommends, said Tobias Hohl, chief of infectious diseases at Memorial Sloan Kettering Cancer Center in New York City, who was not involved in the new research.
The study “didn’t see an impact of recent cancer surgery or an impact of cancer therapies on severe COVID outcomes,” he noted.
The findings from the first published research to examine whether cancer patients are better off getting treatment even if going outside raises their risk of infection, squared with data from 400 patients in his own hospital, Hohl added.
“We also don’t see that major cancer surgery is a risk factor for COVID severity," he said.
The Lancet study looked at 928 cancer patients who caught COVID-19 from mid-March to mid-April in the United States, Canada and Spain.
Advanced age had a significant effect on risk, Choueiri said. “Even in sick young patients compared to healthy old, the healthy old do worse.”
COVID-19 killed 6% of infected cancer patients under age 65, the study showed, but 25% of those who were older. Men were more likely to die than women, as were people who had ever smoked versus nonsmokers, and people with multiple health problems.
Patients who took the drug hydroxychloroquine, often in combination with azithromycin, seemed to suffer to worse outcomes, but that might have been because the drugs were mainly given to the sickest people, Choueiri said.
“We do not know for a fact how real is this,” he said, but the data was suggestive enough that he wouldn’t give either drug to his cancer patients with COVID-19.
Roughly 20% of the study participants had breast cancer and another 16% had prostate cancer – the two most common cancers in the group. The researchers did not find a link between cancer type and death, though Hohl said at Memorial Sloan Kettering, people with lung cancer were more likely to die from the respiratory virus than those with other types of cancer.
“In very general terms, I do feel that patients with lung cancer are at higher risk,” he said, often because of their smoking history and because they have other lung conditions in addition to cancer.
The researchers also looked at obesity, but found no connection between excess weight and risk of death for cancer patients with COVID-19; nor did cancer patients of different races seem to fare differently when they caught the disease.
Funding for the study was largely provided by the National Institutes of Health and the American Cancer Society. Future studies looking at more patients will help improve treatment for cancer patients with COVID-19, Choueiri said.
The relationship between a weakened immune system and COVID-19 outcomes remains unclear. Early in the pandemic, research from China suggested that tamping down the immune system might help patients whose immune systems seem to dangerously overreact to the virus. But treatment with steroids, which limits the immune response and helped combat the SARS virus in the early 2000s, didn’t seem to make a difference.
In Italy, which was extremely hard-hit by the outbreak, patients who had organ transplants – presumably among the most vulnerable – seemed to fare no worse, and sometimes even better, than people with no immune issues, Daley said.
That may be because of an immune system overreaction in many people who suffer the worst effects of COVID-19. Instead of turning off when the virus is mostly vanquished, their immune systems go into overdrive and destroy their own organs.
People who take drugs that tamp down their immune system may be able to avoid this overreaction, June and Daley speculated, though both said it’s still too early to know for sure.