One in four GPs (25%) had seen a referral on the two-week pathway bounced back or refused over the past year and 38% had seen a referral downgraded as less urgent, a GPonline poll found.
Overall, 46% of the 507 GPs who responded said they had had a referral either bounced back or downgraded - and of these, almost a quarter said the patient later turned out to have cancer.
The findings suggest that more GPs are struggling to refer patients for urgent cancer scans now than two years ago, when a similar GPonline survey found that one in three had cancer referrals blocked.
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GPs are also being denied direct access to key diagnostic tests for cancer, the survey found. This is despite national directives – such as those set out by the Independent Cancer Taskforce established as part of the NHS Five Year Forward View – that practices should have access to these scans.
GPs, charities and NHS officials condemned delays to cancer treatment, warning that rapid diagnosis was vital. NHS England warned that GP referrals in line with NICE guidance 'should generally not be passed back to the GP for further assessment'.
Most GPs have direct access to blood tests, chest x-ray and ultrasound, the poll found. But only around half have direct access to MRI, CT or endoscopy. In parts of the country, GPs reported that cancer scan access was being reduced.
GPC chair Dr Richard Vautrey said: 'At a time when there is an increased focus on reducing any unnecessary delays in diagnosing cancer, it is a concern that there remains so much variability in the ability of GPs to access appropriate diagnostic services.
'More work needs to be done to remove barriers that are still placed in the way of GPs getting quick direct access to important tests in order to better help and support their patients.'
Dr Richard Roope, Cancer Research UK’s GP expert, said: 'GPs have been working hard to help diagnose cancers earlier, and it would be a shame if this is reversed due to a lack of resources. Investing in diagnostics will not only help cancer patients get an earlier diagnosis, but it could also reduce the demands on general practice, save money in the long run and improve patient outcomes.
'GPs need the support and systems in place so they can use the NICE referral guidelines, helping more patients receive an early diagnosis and a better chance of surviving cancer. To achieve this, diagnostic capacity is key and more must be done to improve access to diagnostic tests in the NHS.'
An NHS England spokeswoman said: 'Rapid and accurate diagnosis is vital for all cancers and NICE has produced detailed guidance for GPs on the warning signs for cancer. If a GP makes a referral in line with this guidance, this should generally not be passed back to the GP for further assessment.
'Across all cancers, patients are now being tested sooner with investment in greater diagnostic capacity including the roll out of one-stop cancer diagnostic services across the country.'