By: Kathy Hubbard
First off, I want to encourage all women over the age of 40 to make an appointment to have their yearly mammogram. It’s October. October is Breast Cancer Awareness Month. If you’re between 40 and 74 you should get screened. If you’re older than that, talk to your primary care provider.
Now that I said that, I want to tell you about a report published on BreastCancer.org’s website by journalist Jamie DePolo that headlined, “COVID and Flu May Activate Breast Cancer Cells in Lungs.” What? Since many of my cohorts are breast cancer survivors, I read on.
“Common respiratory infections caused by viruses may be able to activate sleeping breast cancer cells in the lungs and lead to metastatic disease, according to database and mouse studies,” DePolo wrote. “People with a history of breast cancer may want to consider COVID and flu vaccinations.”
I’m not going to get into the political discussion on vaccinations. I respect your personal decisions. But I will tell you what this study first published in highly technical language in the journal Nature said, as told by DePolo.
“According to the researchers, people with a history of cancer may benefit from protecting themselves against respiratory infections. This includes receiving available vaccines, if possible, and wearing a face mask when in large crowds or enclosed spaces,” she said.
So, how did this study come about? DePolo explained, “During the first two years of the COVID pandemic, scientists noticed an increase in cancer deaths. This increase wasn’t due to deaths from COVID or to delays in cancer screening and treatment. So many researchers began to wonder if there was a link between respiratory infections and the development of metastatic cancer in the lungs.”
Researchers used a mouse model and analyzed information from two databases to find a link between respiratory infections and metastatic cancer. The data was collected before the COVID shots existed.
The senior study author was James DeGregori, PhD, the deputy director of the University of Colorado Cancer Center. He said, “Dormant cancer cells are like the embers left in an abandoned campfire, and respiratory viruses are like a strong wind that reignites the flames.”
DePolo explained that “researchers found that the cancer cells’ activation was caused by a protein called interleukin-6. Immune cells release this protein in response to infections or injuries. Medicines that target interleukin-6, which are available, might be able to prevent or slow the waking of cancer cells after an infection. But more research is needed to see if this approach works.”
The researchers then looked at records from the Flatiron Health database regarding women who had been diagnosed with breast cancer in January 2011 or later, to find out how many of them had developed lung metastases after testing positive for the coronavirus, between then and August 2023.
“During about eight years of follow-up, women who had COVID-19 were about 50 percent more likely to be diagnosed with metastatic breast cancer in the lungs than women who didn’t have COVID-19,” DePolo reported.
“From the Biobank database, the researchers analyzed information from 4,837 people who were diagnosed with early-stage cancer before Jan. 1, 2015 — five years before the start of the pandemic. People who tested positive for COVID-19 before December 2020 had almost double the risk of dying from cancer than people who tested negative,” she said.
The result of this study’s finding is that people with a history of cancer should definitely have a conversation with their healthcare providers to ascertain if preventive vaccinations such as a flu shot or COVID-19 shot can reduce their risk of metastatic breast cancer in their lungs.
DePolo offers three takeaways from the study. 1. “Among women with a history of early-stage breast cancer, those who tested positive for COVID-19 were nearly 50 percent more likely to develop metastatic breast cancer tumors in their lungs than women who tested negative.”
2. “Among women with a history of early-stage breast cancer, those who tested positive for COVID-19 were nearly 50 percent more likely to develop metastatic breast cancer tumors in their lungs than women who tested negative.”
3. “When mice with dormant breast cancer cells in their lungs were exposed to either the COVID or flu virus, both respiratory infections woke up the cancer cells. Metastatic tumors appeared within two weeks.”
Kathy Hubbard is a member of the Bonner General Health Foundation Advisory Council. She can be reached at [email protected]. This article was written for publication in the Bonner County Daily Bee on October 1, 2025.
