Barbara Clark, threatened to take her primary care trust to court after they refused to fund Herceptin on the NHS.
Barbara Clark has been campaigning for Herceptin to be available on the NHS
The trust eventually agreed to fund the treatment and she is now in remission.
She said the decision by NICE to fund the treatment was "fantastic news".
"It's almost exactly a year since I started this fight and back then almost nobody had heard of Herceptin", she said.
"Is it not remarkable what can be achieved in a year?
"Look at me now I'm in remission, I'm well. I'm not saying it's a cure but at least I've been given a chance."
Ms Clark, a nurse from Bridgwater, Somerset, had threatened to take her case to the European Court of Human Rights to obtain the drug.
She had been faced with the prospect of selling her home to pay privately for the drug.
However, Somerset Primary Care Trust agreed to fund treatment last October.
Ms Clark has continued to campaign for Herceptin to be available across the NHS and earlier this year was honoured for her work at Tesco magazine's Mum of the Year awards.
"I found out about a drug that could save thousands of lives and there was no way I was not going to let it be available to everyone.
"I carried on the fight and I'm really pleased."
She plans to celebrate today's news by going out for dinner with her two sons, Richard, 19, and Ash, 12.
"I know exactly how all those women who will now get the drug will be feeling.
"They will now be able to sleep at night. The most dreadful thing in the world is being told there is a drug but you cannot have it - especially when you have got children.
"It's like dangling a carrot before a donkey, it's the most dreadful thing. "The postcode lottery of who can get the drug is so wrong and hopefully we have managed now to put that right."
More than 5,000 women in the UK with early stage HER2 positive breast cancer will now be suitable to use Herceptin at an estimated cost to the NHS of £100m a year. "NICE have proved its cost effective which is what I've been saying from the start," she said.
"If you don't have to have women come back with late stage breast cancer who will need to be on Herceptin for the rest of their lives it is cost effective to give it for early stage."