Women with a family history of breast cancer are being driven to have their breasts surgically removed without knowing the result of genetic tests because of NHS delays.
Some have waited more than two years for results and have opted for surgery because they could not cope with the anxiety, a survey has found.
Others have been forced to go private in order to get test results quickly.
The test detects the presence of the breast cancer genes BRCA1 and BRCA2, which increase the risk of the disease to 80 per cent in affected women.
It takes a month to complete the tests in the private sector but a survey of 27 genetic counsellors by the charity Breakthrough Breast Cancer found a fifth said they had NHS patients who had waited two years or longer for the results.
Half (55 per cent) had patients who had opted for surgery rather than wait. A similar proportion (59 per cent) had women who had opted to go private.
The delays were due to a backlog of cases that had built up in the health service and changes to the test ordered by the Government, the charity said.
Jeremy Hughes, chief executive of Breakthrough Breast Cancer, said: "It is unacceptable that women are forced to put their lives on hold as they wait so long to get these vital test results. The decision to take such a test is extremely personal, complex and difficult. That some then feel compelled to make crucial healthcare decisions out of fear of developing breast cancer while waiting for the test results is appalling."
The Conservatives' health spokesman, John Baron said: "Labour likes to boast about its bureaucratic cancer targets, but these are useless unless patients benefit from the results. Like radiotherapy waiting times, genetic test results have been subject to delays in recent years. This is despite Labour's promise that by 2006, all results would be received within two to eight weeks.
"It is time for a more holistic approach to cancer treatment which looks at the whole patient pathway rather than creating bottlenecks in the system."
The survey found wide variations between laboratories. Some women who had been tested in 2002 were still waiting for their results, it found.
Genetic testing for breast cancer is a two-stage process. A living relative with breast cancer must be tested first before healthy relatives can be tested to see if they have inherited a genetic fault.
Around 5 per cent of the 41,000 cases of breast cancer diagnosed in the UK each year are due to inherited faults in genes associated with a strong family history of the disease.
The Government's genetics White Paper, which was published in June 2003, committed a total of £3.5m to fund laboratory staff and up to £18m for capital investment to modernise the service. The White Paper set a target of an eight-week wait for diagnostic testing and a wait of two weeks for predictive testing by 2006.
A spokeswoman for the Department of Health said that the Government recognised the importance to patients of obtaining prompt test results. "The laboratories are making excellent progress towards this important goal," she said.
'Your life is waiting in limbo': Oonagh Wilson, mother of two, 39
Oonagh Wilson had a double mastectomy because she could wait no longer for results that would show if she was at a higher risk of contracting breast cancer.
The mother of two lost both her mother and grandmother to breast cancer. Two of her aunts have also been diagnosed with the illness.
Mrs Wilson, 39, from Elgin in Moray, had tests in 2002 to establish if she had a faulty gene, but decided to undergo preventive surgery - a mastectomy and a hysterectomy - in 2003.
More than three years later, she is still waiting for the results of a test to find if her mother had a faulty gene.
"When I went to the geneticist I was told the test results would take about two years but I chose not to wait," she said. "You feel as if you are on your own, just waiting in limbo, but it is actually your life that's waiting in limbo and your children's lives and the rest of your family's lives.
"I wanted to have a full and happy life without having to worry every day about the prospect of having breast cancer."
Mrs Wilson said the results would have a major impact on her life, as well as those of her two children, who may need to consider preventive surgery themselves in the future.
"I think it is absolutely horrendous to have a three-year wait - these are life-threatening and life-changing results," she said.Reuse content