Thousands of people could have undiagnosed lung cancer, health officials have said.

The health service in England said it has only seen around three quarters of the lung cancer patients that it would usually expect to since the start of the pandemic.

Professor Pete Johnson, national clinical director for cancer at NHS England said that this means “a few thousand” fewer people have sought care.

NHS leaders have raised concerns that people are keeping their problems “to themselves” and not coming forward for help because they do not want to put pressure on the health service.

People may also think that some of the symptoms of lung cancer, such as a persistent cough or breathlessness, may also be Covid-19.

Anyone with worrying symptoms, including a cough lasting more than three weeks, persistent breathlessness, weight loss, coughing up blood or chest pain, is being urged to seek help, with health leaders saying that they have a better chance of survival if they are seen early.

Late diagnosis of lung cancer has significantly worse chances of survival compared to cases caught at the earliest stages.

The campaign to encourage people to come forward by the NHS in England and Public Health England is being backed by ex-England cricket captain Sir Andrew Strauss, whose wife Ruth died from a rare form of lung cancer aged 46 in 2018.

Sir Andrew said: “Lung cancer is a risk for everyone – Ruth had never smoked a cigarette in her life and was unbelievably fit and healthy.

“It’s so important that if you notice any loved ones showing symptoms that could be a sign of cancer that you encourage them to contact their GP practice.”

NHS England said more people were coming forward for cancer checks since the first peak of the pandemic, but lung cancer referrals were “at 73% of the same point last year”.

Prof Johnson told Sky News: “We’ve worked really hard in the NHS, even while we’ve dealt with the coronavirus pandemic to make sure that cancer diagnosis and treatment has continued.

“We’re really up to normal except in lung cancer where we’ve only seen about three quarters of the normal numbers of people we would expect to see during that time.

“And I think a lot of that is because the symptoms of Covid, cough and breathlessness, are very similar to those of lung cancer.

“So we want to really make sure that if people have had a cough that’s gone on for more than three weeks if they’ve got any of the other worrying signs such as losing weight, coughing up blood or pain in the chest, that they really do come forward for help.

“We know that people are reluctant to seek help, they’re worried about putting more of a stress on the NHS, but it is very important that we catch lung cancer early because if we do catch it early that’s when we have a really good chance of curing it – if we find it at the earliest stage, more than half of people can actually be cured with something like an operation.

“But if it’s spread around the body when we first catch it then less than 5% of people are alive five years later.”

When asked whether he could identify how many cases have been missed, he said: “It’s about three quarters of the numbers that we would expect to have seen being referred.

“And so that’s probably a few thousand people over the course of the pandemic that we haven’t seen that we would expect to.

“There isn’t a big waiting list or difficulty in getting investigations done.

“The main problem is we just haven’t been seeing people because they’ve been keeping it to themselves.”

NHS England said more than 39,000 people are diagnosed with lung cancer each year.

People whose cancer is caught early at stage one have a 57.7% chance of living for another five years, compared to 3.1% for those diagnosed later at stage four.