Thousands of cancer patients are waiting months for life-saving treatment because of lengthening delays at Britain's cancer centres, doctors said yesterday.

A lack of specialist staff to diagnose and treat cancer patients has resulted in longer waiting times across the whole of Britain, an unpublished study for the Royal College of Radiologists found.

It showed that the number of patients failing to start treatment within the Government's target time has doubled in two years. In 1998, more than two-thirds of patients began treatment within four weeks of a doctor deciding it was necessary, but that proportion fell to 32 per cent in 2000.

The findings, from a survey of the 57 cancer centres in the UK, are embarrassing for the Government, which has made cancer care a top priority for the NHS. While most patients with suspected cancer now see a specialist within two weeks of being referred by their GP, many have to wait weeks for their cancer to be diagnosed and then face further delays for tests showing how far the disease has spread.

Once a consultant has decided on a course of treatment, there is a four-week target for therapy to start. But the study, which looked at 2,500 patients over two years, revealed "widespread failure" to meet this target.

Dr Nick James, of the Institute for Cancer Studies at the University of Birmingham, said long waits for radiotherapy were a "serious problem" that endangered patients' lives.

Dr James issued his warning as a five-year old girl at Birmingham Children's Hospital learnt she would have a life-saving operation that had been cancelled two days earlier because the hospital had spent its budget. Catherine Sharpe, who suffers from the Fanconi anaemia, a blood disease, had expected to start treatment after a bone marrow donor was found. Her parents were told on Friday, less than 24 hours before she was due to have preparatory chemotherapy, that the treatment had been cancelled.

Britain has far lower cancer survival rates than other European nations and a report by the World Health Organisation, due out later this year, is expected to say that 10,000 British people die unnecessarily every year from cancer.

The main reason for the worsening delays is an acute shortage of radiographers, the technicians who operate cancer scanners, with 500 vacancies across Britain. Cancer doctors are also in short supply. Dr James, who ran the Royal College of Radiologists' study, said there were 16 consultancy posts in his department, of which six were vacant.

A Department of Health spokeswoman said measures were being taken to tackle the shortage of radiographers and their numbers had increased by nearly 10 per cent since 1997. She added: "We accept there are still not enough and that people in some places are still waiting too long for treatment."

* Screening for breast cancer could be revolutionised by genetic tests that identify patients who carry a range of genes likely to increase their chance of getting the disease, scientists believe.

At present, women with a strong family history of breast cancer can be tested for a few single high-risk genes. But a study in today's edition of Nature Genetics suggests that testing could be expanded to detect women who are vulnerable to the disease because of the combined effect of many common genes.