Study: Cancer Survivors at Higher Risk of Hospitalization, Death from Flu

New data published in EClinicalMedicine found that survivors of a wide range of cancers are more likely than people in the general population to be hospitalized or die from seasonal influenza, even several years after their cancer diagnosis.

Further, the findings suggest that cancer survivors are also likely to be at an increased risk of severe coronavirus disease 2019 (COVID-19) outcomes, given that both influenza and COVID-19 are both epidemic respiratory viruses with broadly similar risk factors, according to the study authors.

Researchers from the London School of Hygiene & Tropical Medicine analyzed medical records from 1990 to 2014 of more than 630,000 people in the UK, including more than 100,000 survivors of a range of cancers. By comparing the rates of influenza hospitalization and death between cancer survivors and the cancer-free population, the researchers discovered that the risk of these outcomes was more than 9 times higher in survivors from lymphomas, leukemia, and multiple myeloma, compared with those with no prior cancer.

The increased risk persisted for at least 10 years after cancer diagnosis, despite the risks being greater than the general population, and the absolute risks of developing severe influenza still relatively low, with approximately 1 in 1000 survivors of these types of cancer hospitalized with influenza each year, according to the study authors.

Additionally, survivors from other types of cancer also had more than double the risk of severe influenza outcomes for up to 5 years from diagnosis. Even after accounting for other risk factors, such as old age, smoking, socioeconomic status, and body mass index, the same findings persisted.

The researchers also found that cancer survivors were more likely to have other diseases that are associated with increased risk of severe COVID-19 outcomes, such as heart disease, diabetes, respiratory disease, and kidney disease.

Current guidance on who should be considered vulnerable to COVID-19 is largely based on policies developed for previous epidemic respiratory viruses such as influenza. In such guidance, cancer survivors with no recent immunosuppressing treatment are not considered high-risk. Findings from this new study, however, suggest that cancer survivors should be included as a vulnerable group for COVID-19 and influenza management policies, according to the study authors.

"We knew that people with cancer are at high risk of severe outcomes from these epidemic viruses soon after diagnosis, but we found that this increased risk also continues for several years after diagnosis,” said study author Helena Carreira in a press release. “This means that vaccination and other preventative strategies are important considerations for the much broader population of longer-term cancer survivors."

There were limitations noted by the study authors, including that it is not certain that risk factors for severe influenza will have the same associations with COVID-19 and a lack of data on cancer treatments the patients had received.

REFERENCE

Cancer survivors at higher risk of hospitalization or dying from flu. EurekAlert! https://www.eurekalert.org/pub_releases/2020-11/lsoh-csa112720.php. Published November 30, 2020. Accessed December 1, 2020.