The number of people being referred to consultants with suspected cancer has fallen by about 50% during lockdown, it has emerged.
A report by the BBC revealed that during April and May there were 7,500 fewer “red flag” referrals than in the same months in 2019.
They also reported that the number of hospital referrals by GPs for all conditions fell by 48,278.
The study came as England's top cancer doctor urged people to get checked if they are worried about any symptoms.
A poll found one in 10 people would not contact their GP even if they had a lump or a new mole which did not go away after a week, while a third are worried about seeking help during the epidemic.
Professor Peter Johnson, the NHS clinical director for cancer, said failure to get help could have serious consequences for patients and put a greater burden on the NHS.
Why is there a backlog?
Health Minister Robin Swann acknowledged the damage done to normal services by the need to fight coronavirus.
“I don’t think there’s any reason to think that the incidence of cancer has dropped over the last few months, so I think there’s a big backlog.
“I think a lot of doctors are beginning to feel extremely proud of everything that’s been done to cope with the crisis.
“I think we now need to deal with those undiagnosed or untreated cancers.”
Macmillan Cancer Support says the virus has “wreaked havoc” on cancer care nationally, with service disruption and fears over Covid-19 leading to a huge backlog of patients requiring vital treatment.
Lynda Thomas, Macmillan’s chief executive, said the figures are a “sobering demonstration” of the impact of Covid-19 on cancer services.
Sarah Woolnough, executive director of policy and information at charity Cancer Research UK, said the national statistics are “hugely concerning”, and thousands of patients are now in a backlog needing cancer care.
What effect could the backlog have?
Delays in diagnosing new cancers and getting treatment for those who already have the disease could significantly impact survival, according to a study from University College London (UCL) and DATA-CAN, the Health Data Research Hub for Cancer.
When looking specifically at England and analysing data from more than 3.5 million patients, experts estimated that pre-Covid-19, about 31,354 newly diagnosed cancer patients would die within a year in England.
But as a result of coronavirus, they found there could be at least 6,270 extra deaths in newly diagnosed cancer patients - a rise of a fifth.
When all people currently living with cancer are included, the figure jumps to 17,915 excess deaths.
Senior author Professor Harry Hemingway, director of the UCL Institute of Health Informatics, said: "The overall impact of the Covid-19 emergency on deaths in cancer patients could be substantial.
"There are many factors operating here, including rapid changes to diagnosis and treatment protocols, social distancing measures, changes in people's behaviour in seeking medical attention and the economic impact of Covid-19, as well as deaths due to Covid-19 infection."
What can be done?
Professor Peter Johnson, the NHS clinical director for cancer, has pointed to "Covid-free cancer hubs" set up to provide surgery, while independent sector hospitals have signed a deal with the NHS to offer treatment.
Prof Johnson said: "NHS staff have made huge efforts to deal with coronavirus but they are also working hard to ensure that patients can safely access essential services such as cancer checks and urgent surgery.
"From online consultations to the roll-out of cancer treatment hubs, we are doing all we can to make sure patients receive the lifesaving care that they need.
"The wishes of patients and their families will always come first, and we have to make sure that people feel safe coming to hospitals, but my message is clear: people should seek help as they always would."