Breakthrough ... an Australian study has found young breast cancer survivors can boost their chance of remaining cancer-free by inducing artificial menopause. Picture: Thinkstock Source: ThinkStock

The idea is to reduce levels of oestrogen, the female sex hormone known to fuel the regrowth of hormone-sensitive tumours, which account for about 80 per cent of breast cancers in under-50s.

Standard treatment for survivors is a drug called tamoxifen that suppresses the hormone.

However, researchers found that by adding ovarian suppression to this treatment, they were able to further reduce a patient’s risk of tumour recurrence by 22 per cent over five years.

Four to five extra women out of every 100 treated would remain cancer-free under the new regimen, researchers led by Dr Prudence Francis of the Peter MacCallum Cancer Centre wrote in the New England Journal of Medicine on Friday.

Research method ... the diagram shows the treatment of 2033 patients in the primary analysis (shaded) of tamoxifen plus ovarian suppression, compared with tamoxifen alone. Picture: New England Journal of Medicine Source: Supplied

Ovarian suppression was even more effective when tamoxifen was replaced with a drug called exemestane, which blocks oestrogen synthesis, they found.

“For young women, and women who still produce oestrogen after chemotherapy, this is a practice-changing study,” Dr Francis told AAP.

She predicted artificial menopause would become standard practice for survivors of hormone-sensitive breast cancer aged under 35, for whom it was especially effective.

“We have been concerned in the past about the outcomes for the really young women,” she said.

“This study has shown that ovarian suppression for those women under 35 seems to make quite a big difference.”

Check-up ... a technician checks a woman’s breasts for cancer. Picture: Thinkstock Source: News Limited

Most of the 3000 women in the study, a tenth of whom were Australian, were given monthly injections to induce a temporary menopause.

A few opted to have their ovaries removed while others had them permanently suppressed with radiation.

Dr Francis said the benefits of artificial menopause appeared to apply only to survivors who had undergone chemotherapy. Standard tamoxifen treatment appeared equally effective in those who had not.

She added that artificial menopause can induce side-effects such as decreased libido, but appeared quite safe overall.