Q. I have cancer and am being treated with chemotherapy. Am I at increased risk of getting sick and dying from Covid-19?
A. People with cancer, and particularly those with leukemia, seem to have a higher death rate from Covid-19 than the general population, though cancer chemotherapy does not appear to further increase the risk of dying from Covid. Studies, however, have been limited and results are sometimes difficult to interpret.
Many types of chemotherapy work by disrupting the cancer cell’s machinery that allows it to divide and grow so rapidly. Unfortunately, chemotherapy can also disrupt healthy cells that grow rapidly in the body, including the bone marrow cells that make our immune system. Consequently, people receiving chemotherapy are at risk of becoming immunocompromised. The immune system, our body’s primary line of defense against microbes, can also be corrupted directly by blood and bone marrow cancers such as leukemia, which can prevent the immune system from maturing, rendering it incompetent to fight infections.
It’s a logical assumption that people with compromised immune systems would be more susceptible to catching the novel coronavirus and getting sick from it. In one recent study, patients with cancers of the blood and bone marrow had higher coronavirus viral loads, which was associated with higher mortality. But there have been a paucity of population-based studies of coronavirus infection rates in people with cancer, so we don’t know for sure.
A few studies have explored the severity of Covid-19 infections in people with cancer. One study from Britain of more than 1,000 cancer patients seen over a seven-week period during the pandemic found a twofold higher death rate for patients with leukemia, but not for those with other cancers, compared to a similar group of cancer patients from three years earlier, before Covid.
In another study of more than 900 patients with ongoing or previous cancers and Covid-19 infections from the United States, Canada and Spain, 13 percent died and 26 percent either died or had illness severe enough to require intensive care. These rates are much higher than for the general population; among those with Covid-19, the estimated case-fatality rate is about 3 percent in the United States. Cancer patients receiving chemotherapy did not appear to have higher death rates or more severe disease than other cancer patients, though in patients with cancers of the blood or bone marrow, such as leukemia and lymphoma, 14 percent died and 35 percent developed severe illness.
Another international study of almost 200 patients with chronic leukemia found even higher death rates from Covid-19, 33 percent, though again, rates were no greater for those receiving chemotherapy. Interestingly, patients receiving palliative cancer care, which focuses on improving quality of life and providing symptom relief rather than active cancer treatment, were more likely to die outside of an intensive care unit, likely because they declined aggressive therapy given their cancer prognosis.
In an ongoing Covid-19 registry through the American Society of Hematology, the death rate among almost 600 patients with blood and bone marrow cancers was high, at 20 percent. More than half of patients were hospitalized, and 23 percent were sick enough to require a stay in an intensive care unit. More than 50 patients decided to forego I.C.U. admission and chose a palliative treatment approach, illustrating the difficulty in interpreting Covid-19 severity and death rates in patients who have other serious illnesses like cancer.