The Link Between COVID-19 and Cancer
A new study published in JAMA Oncology has found an association between severe COVID-19 infection and underlying, undiagnosed cancer. The findings suggest that screening hospitalized COVID-19 patients for cancer could potentially save lives.
About the Study on COVID-19 and Cancer
The study analyzed electronic health records from over 3 million patients in the United States. Of those patients, just over 35,000 were hospitalized for COVID-19 between March and December 2020. The records were examined for a diagnosis of cancer within 1 year before and 30 days after being hospitalized for COVID-19.
The rate of newly diagnosed cancer after being hospitalized for COVID-19 was compared to two control groups - hospitalized patients who tested negative for COVID-19, and patients hospitalized prior to the pandemic in 2019.
Key Findings: Increased Cancer Diagnoses After COVID-19 Hospitalization
The key findings from the study were:
- Cancer diagnoses were more common in patients hospitalized with COVID-19 compared to those hospitalized without COVID-19
- The most common types of cancers diagnosed after COVID-19 hospitalization were lung, colorectal, breast, pancreatic, and blood (lymphoma/leukemia) cancers
- Blood cancers, including lymphomas like Hodgkin's lymphoma, had the highest risk of being diagnosed after COVID-19 hospitalization compared to hospitalized patients without COVID-19
Based on their findings, the study authors conclude that COVID-19 symptoms may be masking underlying undiagnosed cancers. They suggest that Cancer screening for high-risk patients recovering from severe COVID-19 could improve cancer outcomes.
Can COVID-19 Cause Blood Cancers Like Hodgkin's Lymphoma?
While the study found an association between COVID-19 hospitalization and increased rates of subsequent cancer diagnoses, it does not show that SARS-CoV-2 infection directly causes cancer.
However, COVID-19 does cause changes in the immune system that could potentially enable cancer formation and growth. More research is needed specifically on if and how SARS-CoV-2 may lead to lymphatic cancers like Hodgkin's lymphoma.
How COVID-19 Affects Immune Function
When SARS-CoV-2 infects the body, it triggers an intense inflammatory immune response aimed at eliminating the virus. This involves:
- Increased production of cytokines like interleukin-6 (IL-6)
- Activation of inflammatory cells like macrophages
- Reduced numbers and function of infection-fighting lymphocytes
In severe cases, this dysregulated immune response leads to "cytokine storm" - cell damage, organ failure, and sepsis. The high levels of inflammation, low immune cell levels, and cell damage from COVID-19 could enable cancer formation.
Potential Mechanisms Linking COVID-19 and Lymphoma
While more studies are needed, some potential ways SARS-CoV-2 could contribute to lymphatic cancers like Hodgkin's lymphoma include:
- Increased genomic instability - Cell damage from inflammation could cause errors in cell replication that lead to cancerous mutations
- Disruption of anti-tumor immunity - Lower numbers of lymphocytes like natural killer cells reduces elimination of cancerous cells
- Increased growth signaling - High IL-6 levels promote cell proliferation pathways involved in cancer growth
Additionally, some cancer treatments like chemotherapy significantly impair immune function. This leaves cancer patients more vulnerable to severe outcomes with COVID-19. Disruptions in cancer screening and treatment early in the pandemic may also have enabled progression of undiagnosed Hodgkin's lymphoma.
Screening for Blood Cancers After COVID-19
Based on the study results, the researchers recommend targeted screening for common cancers in patients recovering from hospitalization for severe COVID-19 illness. This includes:
Who Should Be Screened?
Cancer screening should be considered for patients with severe COVID-19 illness requiring hospitalization, especially with:
- Prolonged lack of recovery of normal senses like taste/smell
- Unexplained weight loss
- Fevers without infection identified after recovery
- Night sweats, fatigue, and shortness of breath persisting after recovery
What Screening Tests Should Be Done?
Based on the common cancers identified in the study, the following screening should be considered for appropriate patients:
- Blood tests: Complete blood count (CBC) to scan for leukemia
- Imaging: Chest X-ray or CT scan to check lungs for lesions
- Lab Testing: Examination of blood oxygen for signs of colon cancers
- Endoscopy/Colonoscopy: For patients with risk factors like age, family history of CRC/Pancreatic cancer
Targeted screening of patients recovering from COVID-19 for common cancers could potentially detect cases at earlier stages and improve outcomes.
When Should Cancer Screening Be Done?
The study found cancer diagnoses peaked 12 weeks after hospitalization for COVID-19. Based on this, they recommend initiating screening tests starting at around 90 days after a patient has recovered from acute infection.
Ongoing monitoring for new signs/symptoms for at least 1 year after infection is also advised based on timeframes when study patients were diagnosed with cancer following COVID-19 hospitalization.
Conclusion
In summary - a recent study found increased rates of diagnosed cancers, especially blood cancers like Hodgkin lymphoma, after hospitalization for severe COVID-19 illness. This may be due to COVID-19 symptoms masking underlying cancers, combined with pandemic delays in routine cancer screenings.
While COVID-19 has not been definitively shown to directly cause lymphatic cancers, the cell damage, inflammation, and loss of immune surveillance it triggers could potentially enable formation and growth of lymphomas.
Targeted screening for common cancer types in patients recovering from severe COVID-19 infections could help detect cases at earlier stages and improve outcomes.
Disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult with a healthcare professional before starting any new treatment regimen.
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