Elkrief A, Wu JT, Jani C, Enriquez KT, Glover M, Shah MR, Shaikh HG, Beeghly-Fadiel A, French B, Jhawar SR, Johnson DB, McKay RR, Rivera DR, Reuben DY, Shah S, Tinianov SL, Vinh DC, Mishra S, Warner JL. Learning through a Pandemic: The Current State of Knowledge on COVID-19 and Cancer. Cancer Discovery. 2021 Dec 10. doi: 10.1158/2159-8290.CD-21-1368
The results and/or conclusions contained in the research do not necessarily reflect the views of all CITF members.
Cancer patients have faced severe challenges throughout the COVID-19 pandemic. In addition to being at higher risk of infection from SARS-CoV-2, the burden placed on the healthcare system has led to delays in cancer screening, diagnosis, and treatment, which have had grave consequences. A review article, published in Cancer Discovery and co-authored by CITF-funded researcher Dr. Donald Vinh from the Research Institute of the McGill University Health Centre, provides a comprehensive overview on the current state of knowledge about cancer and COVID-19 and the many obstacles faced in gathering evidence for cancer patients during the pandemic.
Immune response to SARS-CoV-2 infection in cancer patients
Many cancers and cancer therapies cause immunosuppression. Thus, patients have reduced immune responses to COVID-19, and COVID-19 vaccines, and are often unable to clear the infection. The severity and duration of the illness are seen to be dependent on the type of cancer, the nature of their therapy, genetic factors, and the variant of SARS-CoV-2 causing the infection.
Symptoms, severity, and recovery from COVID-19 in cancer patients
While the clinical presentation of COVID-19 is similar to what is experienced by individuals without cancer, cancer patients are more likely to be hospitalized and die from the infection. Individuals with advanced stage cancer and with recent diagnoses (less than 6 months) are at higher risk of severe outcomes. Due to their propensity to severe and prolonged illness, cancer patients are also more likely to suffer from long COVID – a variety of side effects that can last for months beyond recovery from COVID-19 itself – than individuals without cancer.
Impact of cancer therapies on SARS-CoV-2 infection
There is insufficient data to determine whether cancer immunotherapies and cytotoxic chemotherapy influence COVID-19 severity. Accumulating evidence suggests that blood cancer-specific therapies exacerbate disease severity, most likely due to their immunomodulating properties. Overall, the authors write there is limited evidence that any systemic cancer therapies are protective against COVID-19, although several studies examining the effect of cancer therapies on COVID-19 are presently ongoing.
Treatment of COVID-19 in infected cancer patients
Treatment recommendations for cancer patients with COVID-19 mirror the guidelines used for the general population. Special attention to the combination of cancer and COVID-19 therapeutics and palliative care is needed and should be managed at the discretion of medical teams.
Safety and effectiveness of COVID-19 vaccines in cancer patients
Cancer patients were excluded from clinical trials of COVID-19 vaccines. Real-world data has since indicated that the vaccines are safe and well tolerated in cancer patients, irrespective of cancer type, stage, and treatment. However, individuals with cancer, especially blood cancers, are more likely to have impaired immune responses to the vaccines compared to individuals without cancer, putting them at higher risk of disease. Lower levels of binding and neutralizing antibodies and T-cellular immunity in this vulnerable population have led to recommendations for third, and possibly additional, doses of vaccines. The CITF and the former Vaccine Surveillance Reference Group (VSRG) (now the Vaccine Surveillance Working Group) support studies tracking the safety and effectiveness of COVID-19 vaccines in people with blood cancers (lead investigator Dr. Arianne Buchan) and solid tumour cancers (lead investigator Dr. Glenwood Goss).
Cancer care during the pandemic
Delays and cancellations in cancer screening, prevention, therapy, and surgeries due to widespread suspensions of healthcare services during the pandemic have had grave consequences. Examples include extensive underdiagnosis and delayed diagnosis of cases and a marked increase in rates of disease advancement and cancer-related deaths. Furthermore, the psychological impacts of social isolation and pandemic-induced stress in this population intensifies the need for psychosocial support moving forward. Also, while the pivot to telemedicine has been instrumental in continuing the delivery of care, it is not accessible to everyone and may deepen inequalities for those who are disadvantaged and marginalized.
The trials and tribulations of cancer research during the pandemic
As in other areas, cancer research suffered deeply from the effects of the pandemic and misinformation. Moving forward, an emphasis on studies that are reliable, plausible, inclusive, and representative are needed to improve care and outcomes for cancer patients and individuals at risk of cancer during the COVID-19 pandemic.