At just 39, Ms Williams is not considered to be in the main age risk group for developing breast cancer. But nearly 10 per cent of breast cancer sufferers are under 40 when diagnosed.

The nation was shocked to learn of actor Belinda Emmett's diagnosis at 24 and death at just 32, while singer Kylie Minogue was 36 when diagnosed and is in remission.

With no family history of the disease, Ms Williams had given herself the odd breast self-examination but never considered breast cancer a possibility. The tissue of her breasts had always felt a bit dense and she didn't really know what she was feeling for.

She asked her GP to check her breasts in June during a routine Pap smear, and she mentioned her left nipple seemed inverted, which she had put down to losing 25 kilograms.

The only reason she even brought up the issue was because she had experienced a sharp pain when one of her children knocked her in the chest.

An eight-centimetre tumour was the reason.

Ms Williams is now having intensive chemotherapy to shrink the tumour before a likely mastectomy.

Her oncologist is confident it is working, but like most cancer patients she waits for the next round of scans and measurements that will decide the next step.

Ms Williams is only too happy to see more women have routine screening - particularly through the free BreastScreen program that operates in the ACT and nationally.

But she worries the focus on regular screening from the age of 50 - with free mammograms for those over 40 - may breed complacency among younger women.

''All woman, from the time they are teenagers, need to be getting their breasts checked by a doctor. Don't wait until you get to the age of 40,'' she said.

''I don't think any age is too young. It needs to become routine. It can happen to anyone and any changes whatsoever that a woman might notice in her breasts need to be checked by a professional.''

According to the most recent statistics, the median age for breast cancer diagnosis in the ACT is 57 years while the median age at death is 63. Just over 20 per cent of cases are diagnosed at 40 to 49 while 53 per cent are diagnosed at 50 to 69.

Breast cancer is the most common cancer among females in the ACT and the ACT also has the highest rate of breast cancer in the nation.

The chief executive of Breast Cancer Network Australia, Maxine Morand, said: ''Mammograms are not effective on younger women's breasts. Breast cancer is most common in women aged over 50. However, this doesn't mean younger women aren't at risk. Younger women should regularly self-check their breasts for any changes and see a GP if they notice any changes.''

Women under 40 without a family history of breast cancer do not have access to the free public screening process. Private screening can cost up to $500 with associated hospital costs and gap payments for any treatment on top of that.

Ms Williams, who has private health insurance, said she had been surprised by the thousands of dollars in out-of-pocket expenses her family had faced in the wake of her diagnosis. ''We are very fortunate we have the means to pay, but it is another burden at a time we are dealing with so much.''

She felt a responsibility to stay in the private system so as not to add weight to the already burdened public system.

Her children Caitlyn, 11, Joel, 7, and Hannah, 5, are quite matter of fact about their mum's battle and life goes reassuringly on with school and homework, meals and play.

Her husband, Dan, has taken long-service leave to help look after the family, and the only good thing to come out of the trauma of the past few months has been spending time together and being supported by loving friends who have stacked the freezer to breaking point.

Privately, Ms Williams quells her terror about not seeing her children grow up. ''The five-year survival rates are very good in the ACT, but 44 is nowhere near enough for me. I need to know I am going to be around for a lot longer than that,'' she said.

While breast cancer fund-raising and awareness is symbolised by the colour pink, Ms Williams said there were few diseases more ugly.

''I stand here with no hair, no eyebrows, no eyelashes, my nails painted black to stop them falling off. This is a brutal, nasty, nasty disease. I don't think people really understand how awful it is.

''I'd hate for any woman to assume she was too young for this. We all need to be alert, no matter what age we are.''