Certain cancer treatments may heighten danger from Covid-19

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  • A study found that Covid-19 patients with cancer had a higher risk of dying
  • Patients treated with immunotherapy and chemotherapy had the highest risk of dying after contracting Covid-19
  • This finding should, however, not deter patients from getting cancer treatment as cancer is more deadly than Covid-19

People with cancer are at increased risk for severe Covid-19. Now, a preliminary study suggests that certain cancer therapies may heighten those odds even further.

Researchers found that of 3 600 US cancer patients who contracted Covid-19, the highest risk of death was among those who'd received cancer treatment within the past three months.

And the type of therapy mattered: Patients treated with immunotherapy plus chemotherapy faced the highest risk of dying after contracting Covid-19.

Experts stressed that the findings should not deter cancer patients from getting lifesaving or life-prolonging treatment.

Cancer more deadly than Covid

"We don't want people delaying care," said lead researcher Dr Trisha Wise-Draper, an oncologist at the University of Cincinnati Cancer Center. "The cancer is more deadly than Covid."

Instead, she said, the findings offer more insight into which patients are at greatest risk of becoming severely ill should they contract Covid-19.

Cancer immunotherapy includes various approaches to boosting the immune system's tumour-fighting abilities.

Severe cases of Covid-19, meanwhile, often involve an out-of-control immune reaction called a cytokine storm. That raised concerns that cancer patients on immunotherapy might be at particular risk of dying if they contract the infection.

But earlier research showed no clear evidence that immunotherapy alone made Covid-19 complications worse, according to Wise-Draper.

These latest findings, she said, suggest it's the combination of immunotherapy and chemo drugs that carries the biggest risk.

A need for vigilance

Among patients on both therapies who contracted the new coronavirus, 29% died. High risks were also linked to chemotherapy alone, and to "targeted therapies" – particularly drugs that deplete the immune system's B cells, Wise-Draper said.

Those drugs – including rituximab and obinutuzumab – are used to treat certain cancers that arise in B cells. The problem is, B cells also make antibodies that help the body fight off infection.

Of all patients who'd had targeted therapy in the past year, 20% died after contracting Covid-19 – the same death rate as patients on chemo alone. Meanwhile, the death rate among immunotherapy patients was 18%.

To put those numbers into some context, the researchers also looked at Covid-19 patients who'd had cancer but received no treatment for it in the previous year. Of those patients, 14% died.

That rate is still high, Wise-Draper pointed out. She said it underscores the need for vigilance even among people not on active cancer treatment: Physical distancing, mask-wearing and other preventive steps are critical.

Results highly actionable

The study found no evidence that current or recent hormonal therapy added to cancer patients' risks. In fact, those patients had the lowest death rate after contracting Covid-19, at 11%.

The findings were presented on 19 September at the virtual annual meeting of the European Society for Medical Oncology, held online due to the pandemic. Like most research presented at meetings, the study is considered preliminary until it is published in a peer-reviewed journal.

But the results are important, said Dr Joshua Brody, director of the Lymphoma Immunotherapy Program at Mount Sinai, in New York City.

The study "illuminates critical statistics that cancer patients and doctors need to be aware of," Brody said.

"Fortunately," he added, "the results here are highly actionable."

'Each person is different'

Cancer patients on either chemo or drugs that deplete B cells should be monitored closely before and during treatment, according to Brody. And that, he said, should include routine Covid-19 screening, plus a quick response if a patient does become sick – which could mean hospitalisation and treatment with the drug dexamethasone.

The findings are based on about 3 600 Covid-19 patients from across the United States who'd ever received systemic cancer treatments (therapies other than surgery or radiation).

More than half of all patients ended up in the hospital. Overall, those treated for cancer within the past year had a higher risk of dying than those whose treatment was farther into the past – except when it came to hormonal therapy. Treatment within the previous three months generally carried the greatest risk.

According to the American Cancer Society, most people treated for cancer in the past – especially if it was years ago – are likely to have normal immune function. But, the group added, "each person is different", and it urges cancer patients and survivors to talk to their doctor about their situation.

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