Because people with cancer have largely been excluded from the clinical trials to evaluate the efficacy of COVID-19 vaccines, there is ongoing discussion about whether people with cancer therefore have similar immune responses to people without cancer.
It's led by Matthias Preusser, MD, Head of the Division of Oncology in the Department of Medicine I at the Medical University of Vienna, and his colleagues to collect data on SARS-CoV-2 antibody levels in people with cancer who have been vaccinated against COVID-19, and compare them to antibody levels of vaccinated individuals without cancer. Their findings were published in JAMA Oncology online ahead of print in September (2021; doi: 10.1001/jamaoncol.2021.5437).
And the study did indeed find wide differences between SARS-CoV-2 antibody levels in people with cancer and healthy health care workers without cancer (who served as the control group in the study). Here's more on what Preusser told Oncology Times about the findings and their significance.
1 What were the key findings from your work and what populations did you study to reach these conclusions?
"Our key findings are that SARS-CoV-2 antibodies can be detected in patients with solid and hematological cancers after vaccination, although at lower levels than in healthy people. Furthermore, we saw that some types of cancer treatment, particularly chemotherapy and CD20-depleting therapies, suppress the production of SARS-CoV-2 antibodies after vaccination.
"After full vaccination, antibody levels were significantly higher in healthy people than in patients with cancer. While the median anti-S antibody levels were 2,500 U/mL in healthy controls, it was 117 U/mL in patients with cancer. At this point, it is unclear what this difference means in terms of level of protection from infection with SARS-CoV-2 or the severity of COVID-19 disease, but it does indicate that patients with cancer may be less protected by vaccinations than healthy persons.
"Our data are in line with previous reports, but come from the largest cohort investigated so far. We included a total of 595 patients with a wide range of solid and hematological cancers and antineoplastic treatments, and 58 health care workers.
"We included a wide spectrum of tumor types treated at two large hospitals: one academic center in Vienna, Austria, and a communal hospital in a rural area of Meran, Italy. Our cohorts included patients with cancers of the respiratory, gastrointestinal, and genitourinary tracts, as well as lymphomas, myelomas, and leukemias, among others. Our data, therefore, reflect the real-life situation at many cancer centers worldwide."
2 What then are the implications of the results of your study for people with cancer and the doctors and clinicians managing their care?
"Our advice is that patients with cancer and health care workers should undergo vaccination regardless of their tumor type, but the type of cancer therapy needs to be considered. In patients undergoing active chemotherapy and patients with CD20-depleting therapies such as rituximab, obinutuzumab or ibrutinib, the level of protection by vaccination seems to be impaired.
"And we recommend strict safety measures, including regular testing for SARS-CoV-2 infection, social distancing, and appropriate hygienic behavior for such patients.
"Patients with cancer develop antibodies after COVID-19 vaccination, but at lower levels than healthy persons. Importantly, chemotherapy and anti-CD20 therapy limit the immune response and patients undergoing such treatments should be protected from SARS-CoV-2 exposure."
3 What's the next step of your work?
"The next steps are to better understand how antibody levels, and also measures of cellular immunity, can be used to make clear statements about the level of protection from COVID-19 in individual cancer patients.
"In addition, we need dedicated clinical trials that define the optimal SARS-CoV-2 vaccination strategies for cancer patients, particularly those with impaired response to conventional vaccination regimens."
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