Tens of thousands of suspected cancer patients are facing waits of more than a month to find out if they have the disease because of delays in analysing scans and x-rays.

Radiologists and cancer experts have warned that the hold-ups could endanger patients’ chances of survival if the tests confirm they have a malignant tumour.

The Royal College of Radiologists (RCR) said that the NHS’s “chronic shortage” of specialists who can interpret CT and MRI scans and x-rays lies behind the problem.

Cancer charities criticised the delays in diagnosis as “unacceptable” and said that they produced anxiety for patients and could affect how long a patient lives for.

A “snapshot survey” the RCR conducted on 16 October of 50 NHS radiology departments in England, about a quarter of the total, found that while a few had no delays, others faced “major issues”.

The sample, which included both large urban teaching hospitals and small rural hospitals, were asked how many imaging examinations – x-rays and CT and MRI scans – had waited more than 30 days to be read, or “reported”, by a radiologist.

It found that 81,137 X-rays and 1,697 CT and MRI scans had not been analysed for at least 30 days, even though the expectation in the NHS is that such potentially vital diagnostic tests should be examined within a week at most, in case they prove significant.

“If this reflects the national picture, about 300,000 patients are currently waiting more than a month for their x-rays to be analysed and about 6000 patients have waited more than a month for the results of CT and MRI scans,” the college said.

The implications of these long waits include: “Potential to cause delays in diagnosing cancer and other serious illnesses; anxiety for patients waiting for test results; wasted journeys for patients expecting test results; [and] waste of time and other resources, not just in radiology but throughout the healthcare system”, the RCR added in a statement.

“This snapshot survey raises serious concerns for patient safety,” said Dr Giles Maskell, the RCR president. “Although most of these X-rays and scans will not show serious abnormalities, some will show findings which would allow an expert to diagnose cancer or another serious condition at a stage at which it could be cured.”

Maskell highlighted the fact that the UK has only 48 trained radiologists per million population, while Germany has 92, Spain has 112 and France has 130. He called on NHS England and Health Education England, which runs NHS workforce planning, to urgently boost radiologists’ numbers.

Professor Mary Evans, a lay member of the RCR’s ruling council, said: “If the RCR’s survey is representative of what is happening around the country, then this is unacceptable for patients. The stress and worry patients suffer while waiting for radiology test results is considerable and the NHS should not be allowing that to happen.”

The Care Quality Commission, the watchdog of NHS standards in England, recently decided to examine analysis times for diagnostic imaging as a routine part of the more robust inspections it has been carrying out since the Mid Staffs scandal. That may ultimately shorten waiting times.

Harpal Kumar, the chief executive of Cancer Research UK, said: “Reporting delays of this magnitude are unacceptable for patients and urgent action must be taken. We know that in some other countries in Europe, scans are reported in as little as 24 hours. Timely diagnosis and prompt access to treatment for cancer, and other diseases, can make all the difference in improving survival. Patients need the assurance that suspected cancer is taken seriously and is prioritised by the NHS.” The NHS must start training more radiologists as an urgent priority, he added.

Dr Rosie Loftus, a GP who is Macmillan Cancer Support’s joint chief medical officer, said: “It is incredibly worrying that thousands of patients are facing significant delays in receiving their x-ray and scan test results. Macmillan Cancer Support has recently undertaken a survey of our GP leads which supports the findings of the Royal College of Radiologists in terms of these lengthy and variable waiting times for cancer patients.

“It is vital that people with cancer have rapid access to test results so they are diagnosed early, are treated quickly and have the best possible chance of survival. Of course, lengthy delays can also cause extra worry and concern for people at a time when they are most vulnerable,” Loftus added.