Cancer patients, treated as an “at-risk” group throughout the pandemic, may actually have a heightened ability to fight the coronavirus, according to Israeli scientists.
COVID-19 is believed to hit hardest when it turns the body’s best weapon — the immune system — on itself, triggering a potentially lethal immune overreaction called a cytokine storm.
But among cancer patients, drugs often make the immune system weaker than normal, and Haifa researchers think this limits the impact of the virus, because it has less of an arsenal to turn on the patient.
“Our hypothesis is that because the immune system is weakened, reaction to the virus is much less than in the general population,” Prof. Yuval Shaked, a cancer expert from the Technion-Israel Institute of Technology, told The Times of Israel.
He said that a small study conducted at Rambam Medical Center in Haifa and published in the peer-reviewed journal Cancers provides early indication that cancer isn’t the risk factor for serious COVID-19 that people assume.
The Technion-Rambam research comes as oncologists internationally are reassessing some assumptions about the coronavirus and cancer. Rachel Kerr, medical oncologist at the University of Oxford, recently remarked that data being gathered on cancer during the pandemic in the UK will help doctors to “more precisely define the risk to a given cancer patient and move away from a blanket ‘vulnerable’ policy for all cancer patients.”
Shaked’s study found that not even one of Rambam’s 8,000 oncology patients who had appointments between December and June had suffered from coronavirus symptoms and been diagnosed during Israel’s first wave. This includes patients who had appointments booked but didn’t show up.
If the cancer patients reflected the national average at the time, there would have been around two dozen people confirmed as coronavirus-positive.
The Haifa region, which Rambam serves, was affected in the first wave less than other places in Israel, but Shaked, head of the Rappaport Technion Integrated Cancer Center, was still “surprised.” He suspected that cancer patients weren’t avoiding infection, but rather getting infected like others and showing good ability to fight the virus, to the extent they were likely to remain asymptomatic.
To test that hunch, he conducted antibody blood tests on 164 of the oncology patients. He found that 2.4% had fought off coronavirus without even realizing they had become infected.
The bottom line, according to Shaked, appears to be that cancer patients are catching the virus just like others, and in many cases efficiently fighting it.
“I would have expected, based on assumptions about COVID-19 and cancer, to see oncology patients who had been symptomatic, but we found they are likely to be asymptomatic, which is unexpected and interesting,” he said.
Shaked’s team found that cancer patients had almost the same likelihood of unknowingly catching and fighting the coronavirus as staff of a similar age from the Rambam oncology department, which they visit. This 100-strong control group was chosen because it had been exposed to the same environment.
There were no patients with blood cancer in the study, and Shaked said that results would have probably been different if there were, as blood cancers have been shown to be a risk factor for coronavirus.
Shaked and his fellow researchers, including Rambam’s Oncology head, Irit Ben Aharon, are now testing larger numbers of patients to check the theory that cancer patients aren’t only free of additional risk, but actually have a level of protection against the worst effects of COVID-19.
“The treatment for cancer modulates the immune system in a way that the virus may work differently,” said Shaked. “And in the patients we tested, they successfully minimized the symptoms.”
He elaborated: “Cancer patients get drugs that often weaken the immune system. Given the fact that the immune system is relatively low on a regular basis, and the virus uses a strong immune system to start a cytokine storm, the chances of developing such symptoms is low.”