Thousands of women in Oxfordshire are being denied vital three-yearly breast cancer checks that could save their lives.

All women aged 50-70 are entitled to screening every 36 months, but staff shortages at Oxford's Churchill Hospital has meant that almost 14,000 women in the last 18 months were not called back for routine appointments within the time limit.

The Oxford Radcliffe Hospitals NHS Trust, which provides the service, has blamed the delays on a national shortage of mammographers, trained breast x-ray staff, which left them short of almost half their 12-strong workforce.

The problem started in June-September 2006, when only 28 per cent of women, about 1,200, entitled to a screening were called for an appointment within three years.

It hit an all-time low in October 2006 to March this year, when 12 per cent, about 1,050, received 36 monthly screenings - well below the Government's target that 90 per cent should be seen within three years.

Despite improvements, managers said only 14.2 per cent of women due for their three-yearly checks, about 256, were invited for screening last month.

The situation has been branded as appalling by former breast cancer patients.

Gwen Mason, 62, of Woodstock, discovered she had the disease during her first screening 11 years ago.

The former Mayor of Woodstock said: "It's absolutely imperative people pick this cancer up quickly. I was lucky, but I know people who within three years would have died because their cancer was so aggressive."

Oxford City Councillor Susanna Pressel, who battled against the disease in 2005, has asked the Oxford committee of the Oxfordshire Joint Health Overview and Scrutiny Committee to investigate.

She said: "As a woman who's had breast cancer I feel particularly strongly tat screening is important to women. It can mean the difference between life and death."

The screening service uses mammogram x-rays to monitor women for breast cancer.

According to Cancer Research UK, regular checks are important because the earlier breast cancer is discovered, the easier it is to treat.

Clinical trials director Kate Law said: "Many lives are saved every year across the UK by the NHS Breast Screening Programme. Breast cancer is easiest to treat when caught early and we continue to encourage women over 50 to go for screening appointments when invited.

"Cancer Research UK has launched an ambitious set of goals for the year 2020.

"One of these is for two thirds of all cancer cases to be diagnosed at a stage when the cancer can be successfully treated. A fully effective breast screening programme is vital in helping to achieve this."

In Oxfordshire, the ORH service is provided at the Churchill Hospital and in a mobile unit travelling around the county. It is paid for by Oxfordshire Primary Care Trust.

In a PCT report, county public health director Dr Jonathan McWilliam explained that a "significant drop in performance" had been noticed in September last year.

Dr McWilliam said the ORH had now recruited more staff and doubled the amount of hospital screening from one day a week to two. The PCT was monitoring the situation every fortnight.

He added: "There've been many difficulties within the breast screening service over the last six months.

"Early identification by the PCT and a significant effort by the breast screening service has minimised the impacts these difficulties have had on patients and staff alike.

"There's now an active plan in place which will ensure the recovery continues."

It is not the first time staff shortages have impacted on breast screening in Oxfordshire.

In 2003, the Oxford Mail reported that a third of 50-64 year olds were not being seen every three years.

Linda Soderberg, ORH directorate manager of radiology, said it was particularly difficult to recruit radiographers to Oxford, where the cost of living was high.

To encourage them to join the trust, they are offered a 10 per cent pay premium over the national NHS salary of about £27,000.

Mrs Soderberg added: "We had 5.5 vacancies for breast screening radiographers and we also had two people on long-term sick leave.

"We now only have one vacancy and are screening back to our full capacity of about 4,000 women a month."

Breast screening ensured Gwen Mason discovered her cancer quickly.

During her first appointment in 1996, at the age of 51, radiographers saw a tumour.

Three months later she had surgery to combat the disease.

In the five years following her illness, Mrs Mason was given regular checks to ensure the cancer had not returned before she was finally given the all-clear.

Since then she has had one routine screening and is scheduled to have another in the next few years.

Part-time office manager Mrs Mason, 62, of Plane Tree Way, Woodstock, said: "Screening should be a priority in the NHS.

"Even three years is a long time to wait for some people.

"An awful lot can happen in a year.

"The opportunity to be screened should be there even if a women doesn't want to take up the invitation."