Free breast screening through mammograms has helped lift survival rates from breast cancer in the ACT over the past 20 years, but women should never be complacent about breast changes - even if they have had a clear mammogram.
Women under 50 and those with dense breast tissue are at a higher risk of a mammogram not identifying potential cancers and need to be more alert for lumps - particularly if they have a family history of the disease.
The clinical co-ordinator of BreastScreen ACT, Anne Bicknell, said mammography was the most effective way to detect cancer in healthy women between 50 and 74 and had reduced the mortality rate of breast cancer by up to 30 per cent.
But it was not a failsafe test and women going through the screening process were urged to seek medical advice on any breast changes, even if their mammogram came back clear.
Radiologist Jeremy Price said breast image specialists in Australia were reconsidering how they dealt with breast density and mammography screening among younger women, given legislative changes in the US.
Some American states have legislated that women with dense breast tissue are warned that mammograms may be less effective and that they should seek supplemental screening with either MRI or ultrasound.
This followed the efforts of American Nancy Cappello, who was diagnosed with breast cancer in 2003 despite having a clear mammogram. She set up the areyoudense.org website to begin lobbying for change.
Dr Bicknell said there was clear acknowledgement that a mammogram was not a failsafe test and women were advised during the mammogram, and again in writing after receiving their results, that any breast changes should be checked by a professional.
"Women do need to be aware of any breast changes even if they receive a normal result,'' Dr Bicknell said.
''If they find a lump or notice changes to their breast, we advise them to go straight to their doctor for review as further tests may be required."
The sensitivity of screening mammography in the target age group was about 90 per cent as not all cancers could be detected.
Dr Price said women with dense breast tissue needed to be more wary of the limitations of mammograms.
"The inconvenient truth here is that the sensitivity, or detection rate, of x-ray mammography falls to well under 50 per cent in the densest breasts so only half of the cancers that might be present are likely to be detected," Dr Price said.
"Guidelines generally recommend avoiding mammography at least until the mid-30s and there is still some debate about whether routine screening mammography is worthwhile in the 40 to 50 age group."
MRI was not offered as part of routine screening in the population of women eligible for the BreastScreen program.
Women considered at a higher risk of developing breast cancer because
of a strong family history of the disease were referred for risk assessment through the Canberra Hospital Genetic Counselling Service.
They were encouraged to attend for annual screening and benefited from a tailored screening strategy which may include ultrasound and MRI. Since 2009, annual breast MRI has only been covered by a Medicare rebate for women under the age of 50 who face the highest risk of breast cancer based on family history.
Typically this would be a young woman who has at least two first- or second-degree relatives with breast cancer, with at least one of these diagnosed under the age of 40. Women who have tested positive for the faulty BRCA gene are also covered by Medicare.
Dr Price said women with a significant family history or who had extremely dense breasts and were under the age of 50 needed to consider whether to incorporate an MRI into their breast surveillance.
The MRI involves an injection of a contrast agent and lying still inside a magnet bore for about half an hour. These studies took some time to read and results might take a few days, Dr Price said.
The ACT has the highest early breast cancer detection rate and the highest five-year survival rate for breast cancer in Australia.