The National Cancer Intelligence Network said 23 per cent of all cancer cases went undetected until the emergency admission stage.
Pensioners and the poor were most at risk of being diagnosed late. The detection rate is even worse among sufferers of brain tumours or acute leukaemia, with more than half of these cancers diagnosed only in an emergency.
The figures were described as “shocking” last night by leading cancer charities. Spokesmen said a lack of awareness of symptoms among the general population and a failure by doctors to identify the early warning signs were largely to blame.
They called for new screening programmes as quickly as possible and for public awareness campaigns to highlight the symptoms of cancer.
Patients whose cancers are diagnosed only when they reach A&E departments are more likely to have advanced forms of the disease, making it often impossible to treat.
Experts say England’s poor detection rates could explain why the country has much lower survival rates than other countries in Europe. They believe that many hundreds of lives could be saved each year if more early diagnoses were made.
The study comes after the Office for National Statistics disclosed that the cancer death rate among British women was higher than in countries such as France, Italy and Portugal.
Britain has national screening programmes for only three types of cancer: cervical, bowel and breast cancer. Tests are not yet accurate enough for other forms of the disease.
Harpal Kumar, the chief executive of Cancer Research UK, said: “The figure for diagnoses via emergency presentations is way too high.
“This statistic helps explain why we have lower survival rates than we would hope to have, lower than the best countries in Europe.
“We need screening programmes to be rolled out as early as possible and GPs given rapid access to the tests that will enable patients to be moved quickly through the system.” Mr Kumar said people should be better educated about the possible signs and symptoms of different types of cancer.
Prof Sir, the National Cancer Director, who acted as clinical director to the project, said the overall figure of 23 per cent had been “quite a surprise”.
“We need to look at this group of patients and see what we can do to reduce the proportion coming in as emergencies,” he said.
The NCIN, part of the NHS-run National Cancer Programme which coordinates national information on cancer, looked at all English patients diagnosed in 2007 and worked through their files to find when their disease was diagnosed.
The proportion of cancers identified during an emergency varied widely between different types, depending on how easy they are to identify and on general awareness.
Only a small number of skin and breast cancers – 3 and 4 per cent respectively — were diagnosed at emergency, with most identified by doctors or screening programmes.
Overall, 23 per cent of cancer cases were diagnosed during an “emergency presentation” by the patient, most often to A&E departments. Of those with brain or central nervous system cancer, 58 per cent were not picked up until they were seen in hospital, along with 57 per cent with acute leukaemia and 47 per cent with pancreatic cancer.
Patients under 25 and over 75 were the most likely to present as emergencies, as well as poorer ones. These patients were less likely to survive for a year than those whose illness was detected in the doctor’s surgery.
The authors of the study said: “One-year relative survival rates were lower for patients presenting as emergencies than for those presenting via other routes.”
A spokesman for the Department of Health said: “We are committed to improving cancer outcomes. Earlier diagnosis is crucial to match the best survival rates in Europe.”