A “brave and selfless” breast cancer patient has become the first person to trial a pioneering new treatment at the Royal Free Hospital that could save thousands of women.

Despite facing a mastectomy operation and weeks of debilitating chemotherapy Kathe Baker signed up for the trial knowing she had nothing to gain personally from tests that could end breast cancer surgery.

Initially the 79-year-old did not think she could put herself through the trial treatment that took place just 48 hours before she had an operation to remove her breast.

But her mind was changed when she saw a young mother attending her clinic at the hospital in Pond Street, Hampstead.

She said: “Outside there was a mother coming into the clinic with a baby in a pram and that turned me.

“I thought that my life is finished and hers is just beginning and I thought if that would have been me, I would have been devastated.

“A young person beginning her life with a little baby and she’s got breast cancer and I thought yes, I’m going to do the trial and if it saves one person it’s worth it.”

The Royal Free is thought to be the first place in the world to conduct research into the use of photodynamic therapy to treat early breast cancer, which could end the need for invasive surgery.

Patients are given an infusion of a drug which makes cancer cells sensitive to light and a beam of light is then targeted into the infected area through a needle, destroying the cancer cells.

The process takes less than half an hour and is painless, Mrs Baker revealed.

Professor Mo Keshtgar, consultant breast cancer surgeon at the Royal Free, who is pioneering the research, welcomed her brave decision to be the first to trial the treatment.

He said: “The phase one trial is only being done on patients undergoing surgery. We have to have all the evidence before we can begin treatment.

“It was a very brave and selfless act from her because she was not gaining any direct benefit.”

After the treatment Mrs Baker had to lie in a dark room for 48 hours as daylight can affect the skin.

“They put me in a private room on the 12th floor and treated me like a queen, they were brilliant to me,” she said.

“On Sunday I came out, Monday was a Bank Holiday, on Tuesday they operated on me and removed my breast.”

Since the operation the mother-of-three has undergone eight chemotherapy sessions which ended last week, but she hopes the new treatment may eventually save others from the “devastation” of losing a breast.

“I believe Professor Keshtgar will get through his research,” she said. “I’m sure if more people offer to help, they’ll get there. “I would do it again. If you can help somebody, even if it is one person, that would be something.”

The trial has been funded by donations from organisations such as the Royal Free Charity and Killing Cancer.

The public also raised more than £70,000 for the cause when Professor Keshtgar ran the London marathon earlier this year.