GOING through a severe bout of Covid or the flu trigger lung cancer years or even months later, scientists say.
Serious viral infections “reprogram” immune cells in the lungs, making it easier for tumours to grow, an American study shows.
But Covid-19 and flu vaccines – dished out to at-risk groups in the UK – could help prevent these harmful effects, researchers suggested.
Dr Jie Sun, from the University of Virginia (UVA) School of Medicine, said: “A bad case of COVID or flu can leave the lungs in a long-lasting ‘inflamed’ state that makes it easier for cancer to take hold later.
“The encouraging news is that vaccination largely prevents those harmful changes for cancer growth in the lung.”
Researchers urged doctors to keep an eye on patients who’ve recovered from severe Covid, flu or pneumonia.
This may help catch lung cancer early, when it’s still treatable, they said.
Lung cancer is one of the most common types of cancer in the UK, affecting more than 43,000 people a year, according to the NHS.
It’s also one of the most serious, causing more deaths than any other cancer.
It’s often caught when it is more advanced, as the early stages of lung cancer usually cause no signs or symptoms.
Smoking is the most common driver, with targeted lung cancer screening rolled out to ex- and current smokers in England aged 55 to 74.
But people who’ve never picked up a cigarette can also get the disease.
Dr Jeffrey Sturek, who also worked on the study, said: “These findings have important immediate implications for how we monitor patients after severe respiratory viral infection.
“We’ve known for a long time that things like smoking increase the risk for lung cancer.
“The results from this study suggest that we may need to think about severe respiratory viral infection similarly.”
Writing in the journal Cell, UVA researchers explained flu and Covid can injure the lungs.
The team studied the long-term effects of lung injury from respiratory infections in both mice and humans.
Mice that suffered severe lung infections were more likely to develop lung cancer.
They were also significantly more likely to die from the disease.
Serious viral lung infections caused dramatic changes to immune cells called neutrophils and macrophages, which are supposed to protect the organs.
Following illness, neutrophils in the mice’s lungs created an inflamed, “pro-tumour” environment that made it easier for cancer to thrive.
Next, researchers examined data from patients who’d been in hospital with Covid.
They found a significant link between Covid hospitalisation and the development of lung cancer in patients.
Patients were at increased risk of the disease whether or not they were smokers or had other health conditions that might make them more likely to get cancer.
But the increased cancer risk was seen in patients with severe Covid-19, not those who had suffered mild cases.
Those patients actually saw a slight decrease in risk.
Meanwhile, vaccination against Covid and flu appeared to prevent cancer-causing lung changes.
But researchers warned survivors of severe flu and Covid may need to be monitored, as they could face an increased risk of developing lung cancer in the years to come.
“With tens of millions of people globally experiencing long-term pulmonary consequences [from Covid-19], these findings carry significant implications for clinical care,” they wrote.
Dr Sturek suggested: “In some patients who are at high risk for lung cancer based on smoking history, we recommend close monitoring with routine screening CT scans of the lungs to catch cancer early.”
The UK grappled with an earlier than usual surge in flu cases, beginning in November last year.
Infections have since decreased and the virus is now “circulating at baseline levels”, according to the UK Health Security Agency – the same goes for Covid.
But many vulnerable people still end up in hospital with the two infections every year.
UVA scientists said their findings on the biological changes brought on by severe lung infections could lead to better treatments and save lives.
Source : https://www.the-sun.com/health/16069942/severe-covid-flu-may-trigger-lung-cancer/