Women are being denied surgery for breast cancer that could give them an extra three years of life, a cancer charity said yesterday.

The Cancer Research Campaign said older women were often not given the option of surgical removal of a tumour, but instead given only hormonal anti-cancer drugs. Younger women were routinely offered surgery. Scientists claim there is evidence that women over 70 who have surgery live an average of three years longer than women treated only with drugs, prompting the charity to support calls by Age Concern for an end to age discrimination in breast cancer treatment.

"While an operation won't suit everyone over the age of 70, it seems ridiculous that we should continue to deny older women the chance of a longer life," the director general of the campaign, Professor Gordon McVie, said. The treatment of older women was based on "outdated misconceptions", and the report should lead to a "sea change" in attitudes.

Each year about 13,000 women over 70 are diagnosed with breast cancer, and they are the group most at risk from the disease. Butmany doctors believe older women are too frail to have tumours surgically removed and instead prescribe only tamoxifen, a breast cancer drug. There are no clear guidelines on the best course of treatment.

In a clinical trial, scientists from University College London, Charing Cross Hospital and the William Harvey Hospital in Ashford, Kent, monitored 455 women aged over 70 diagnosed with breast cancer. One group was offered surgery and Tamoxifen, while the second was given the drug only. After 12 years, 66 of 225 women in the group that received surgery were still alive, while 42 of 230 patients who received only tamoxifen had survived.

Surgery reduced the risk of dying from breast cancer by 10 to 15 per cent, and extended life expectancy by three years.

Professor Mike Baum, who led the research, said: "Part of the reason older women have been denied surgery is that we've underestimated their life expectancy and undervalued their lives. A healthy woman of 70 can now expect another 14 years of life, and that's surely a period that's worth preserving if we can."

Professor Robert Mansel, a cancer surgeon in Cardiff and chairman of the British Association of Surgical Oncology's breast group, said he thought the study would lead to more women aged over 70 being offered surgery.

"This is usually a matter for the doctor's own discretion, but I certainly think more women should have operations. The reality is that breast cancer surgery is very safe."

He said doctors were bound by training that could be out of date. New guidelines on breast cancer treatment are due to be issued shortly by the NHS Clinical Outcomes Group and are expected to recommend more surgery for older women.

The Cancer Research Campaign and Age Concern called on the Government to end age discrimination in the health service. Dr June Crown, chairman of Age Concern, said: "The prospect of having the fundamental choice of treatment taken away from you on the basis of your age is quite simply age discrimination – whatever the intentions might be."