Australian women in their 20s and 30s are more likely to die from breast cancer than older women.
They're also more likely to suffer physical and psychosocial distress than women over 40, and face greater financial implications from their illness.
The Australian Institute of Health and Welfare Breast Cancer in Young Women report released on Monday shows more than two breast cancers are diagnosed every day among women aged 20 to 39, and at least one young woman dies every week from the disease.
Young women are expected to account for five per cent of new breast cancer cases in Australia in 2015, and 2.1 per cent of breast cancer deaths.
This year, an estimated 795 young women will be diagnosed, and 65 will die.
And while breast cancer is still relatively rare among young women, the report shows those diagnosed have a lower survival rate than women over 40.
The five-year relative survival rate for women aged 20 to 29 is 86 per cent, compared with 90 per cent for women over 40.
Institute spokesman Justin Harvey said there tended to be a higher proportion of very large breast cancers in young women than older women, associated with a lower survival rate.
But even when it comes to small breast cancers, women aged 20 to 39 have a survival rate of 93 per cent, compared with 99 per cent for older women.
The reason for the poorer survival rate is unclear, the report says, but is likely related to differences in cancer characteristics, such as larger cancers and higher grades.
And while all survivors often face emotional, physical and financial challenges as a result of their illness, in the long term young women tend to be more at risk of physical and psychosocial distress, the report says.
"These young women are at a life stage in which they are building careers, establishing relationships and planning for a family," Cancer Australia chief executive Professor Helen Zorbas said.
The report says young victims of the disease feel "too young" to have cancer, have higher levels of fear that the cancer could return than older women and are afraid of loss of fertility and early menopause as a result of treatment.
The financial implications are also greater, because they're more likely to be at the start or middle of their careers, and may find it difficult to re-enter the workforce after treatment.
