After a completed cancer treatment, cancer cells that do not die can lie dormant in the body for years, hidden in organs such as lungs, liver, and brain.
The study shows that respiratory infections such as influenza and covid-19 can awaken the "sleeping" cells according to National Geographic, as referred to by TV4 News.
Researchers have studied mice with dormant cancer cells in the lungs. When the mice were infected with influenza or coronavirus, the cells were activated and began to grow rapidly – only to then return to dormancy. Despite this, the cancer cells had managed to increase a hundredfold, which can increase the risk of recurrence.
Studies of cancer patients during the pandemic also show the connection. For those who got covid-19, the risk of lung metastases and cancer-related death increased, even several years after the original cancer diagnosis.
The reason appears to be the protein interleukin-6, which the immune system uses to combat infections. When the protein encounters the sleeping cancer cells, it helps them to grow instead of remaining dormant.
Many patients can live their entire lives without the cells waking up, but for some, an infection can trigger the cancer again. The researchers therefore urge cancer patients to keep up to date with vaccinations against respiratory diseases.
