Being diagnosed with breast cancer has changed Hollywood star Shannen Doherty's life "for the better", she has said - because it showed her who were her true friends.

The Charmed and Beverly Hills, 90210 actress was honoured with the American Cancer Society's Courage Award in Los Angeles on Saturday, where she revealed she was due to begin radiotherapy after completing chemotherapy.

Doherty, aged 45, has shared her battle with the disease through her social media accounts since being diagnosed last year.

Speaking after she received the award, she said she felt "ridiculously lucky and very blessed".

She thanked her mother Rosa, husband Kurt Iswarienko and friends including actress Sarah Michelle Geller and comedienne Chelsea Handler for their support during her treatment.

"It's this amazing thing where you look at people and realise their worth and what good hearts they have because they're not running," she said.

"That's what cancer does. It strips everything where everyone, including you, is laid bare."

Buffy the Vampire Slayer star Geller presented Doherty with the award at an event at the charity's Giants of Science gala at the Four Seasons hotel.

Fighting back tears, she said Doherty had "always been a courageous person" - but over the past year had become "a one-woman army".

"Fearless yet full of heart, crushing cancer like a slayer - takes one to know one," she said.

"In an age when celebrities are afraid to walk out of the house without make up, Shannen is proudly displaying her shaved head, telling the world if this can happen to me, it can happen to anyone."

Doherty had filed a lawsuit against her former business managers, claiming they left her without health insurance and caused a delay in doctors diagnosing her with the disease. The case was settled in August this year.

Earlier this year she told Entertainment Tonight her cancer had spread to her lymph nodes and in May, she underwent a single mastectomy.