A total of 106,535 people with suspected cancer symptoms were referred by their GP for diagnostic checks in May – just over half the 200,599 referred a year earlier.
Experts would have expected the total number of cancer tests in May to have risen by about 10,000 year-on-year had Covid-19 not been a factor.
About seven per cent of patients sent for tests normally end up requiring treatment – suggesting 7,000 people with cancer may have gone undiagnosed.
The problem is likely to result from patients being scared of being sent for hospital tests due to concerns about contracting coronavirus.
However, a Cancer Research survey yesterday revealed that a quarter of GPs said that some referrals were being “inappropriately turned down” by hospitals because of a lack of capacity and the reduced number of diagnostic tests being done during the pandemic.
Today’s figures showed that the number of monthly cancer referrals increased by 26,962 on the 79,573 in April, when coronavirus deaths were peaking.
Urgent breast cancer referrals also rose month-on-month to 5,371 in May but this was only about a third of the 15,802 in May 2019.
The NHS England figures also showed that the number of people waiting more than 18 weeks for all types of hospital treatment increased by 315,755 in a month to 1,448,357.
The number waiting more than a year for treatment increased to 26,029 in May – up from 11,042 in April and the highest figure since 2009.
A&E attendances remained well below normal levels but the number of people prepared to seek emergency care is increasing.
A total of 1,411,300 people went to casualty in June, 33 per cent down on the 2.1 million in the same month a year earlier, but almost 150,000 more than in May.
The number of patients admitted for routine treatment in hospitals in England was down 82 per cent in May compared with the previous year.
NHS England said this was “likely to be a result of the Covid-19 response”.
In London, A&E attendances rose month-on-month from 219,265 in May to 253,344 in June. But this is down 40 per cent on the 426,528 in June 2019.
Dr Nick Scriven, immediate past president of the Society for Acute Medicine, said: “Clearly NHS performance across the board continues to be hugely affected by Covid-19, though we must also remember performance has been poor for a lot longer than that and questions need to be answered as to how we ensure the sustainable future of the service.
"We are very concerned about the growing crisis in accessing diagnostic tests, with the total number of patients waiting six weeks or more from referral for one of the 15 key tests at 571,500 - 58.5 per cent of the total number of patients waiting - which is shocking given the target is one per cent."
Michelle Mitchell, Cancer Research UK’s chief executive, said monthly referrals were down 47 per cent on a year ago.
She said: “This is yet more worrying evidence of the impact Covid-19 has had on cancer patients and services. While it’s encouraging that the number of urgent cancer referrals has started to recover since the steep decline in April, the latest figures for May are still worryingly low.”