Proposed changes to breast cancer screening are attracting emotional responses in the media. Kate Woods speaks to the experts to set the record straight.
ALMOST 20 years ago, when state and federal health ministers joined together to fund a national mammography screening program, the age-standardised death rate from breast cancer was 30.6 deaths per 100,000 women.1
For women aged 50-69 years, the rate was even higher: almost 67 deaths per 100,000 women.1 At the time, estimates were that if the new program – which became known as BreastScreen Australia – was able to screen 70% of women aged 50-69 years, it would reduce mortality from breast cancer by 16 per cent.2
BreastScreen Australia is now one of the most comprehensive population-based screening programs in the world. It has helped reduce mortality rates by 21%-28%, despite a participation rate of only 56 per cent.2
While many, including University of Western Australia professor of surgical oncology Christobel Saunders, applaud the success, it hasn’t stopped the program striving for its original goal of a 70% participation rate.
“BreastScreen Australia has done a fantastic job in terms of service delivery,” Professor Saunders says. “This is a significant relative mortality reduction.”
Despite the success, a recent evaluation has led an expert advisory group to recommend several controversial changes to help the program reach its goal.
A major, evidence-based recommendation was to exclude women aged 40-44 years and women 75 years or older. The experts explained that randomised controlled trials had been unable to show a mortality benefit for younger and older women. For this reason, they suggested that screening preference be given to those in the target age group: 50-69 years.
“In 2008-09, an estimated 90,000 women aged 40-44 years... will attend for screening. Not screening women in the 40-44 age group would provide the capacity to increase the participation rate of women aged 50-69 from 56.2% to 60.1 per cent.”
The experts also suggested changes to the screening of women at a higher risk of breast cancer. For example, they suggested women with a previous history of invasive breast cancer or ductal carcinoma in situ wait five years from diagnosis before entering the program.
Some groups are not so sure these recommendations are a step in the right direction. One such organisation is Breast Cancer Network Australia (BCNA). It disagrees with the decision to restrict the availability of mammograms for women with a previous history of breast cancer.
“We think it’s highly inequable [that] women are able to access mammograms at no cost when they are well, but not when they have been diagnosed and have extra medical expenses to contend with,” says Michelle Marven, BCNA policy manager.
But BCNA’s main complaint is with the experts’ recommendation to exclude those younger than 45 and older than 74.
“We agree it’s important to ensure screening numbers are increased, that more women within that target age are attending the BreastScreen program or are undergoing regular screening... but one missed cancer is just one too many.”
While Ms Marven was unsure how many cancers would be missed, evidence from the BreastScreen Australia evaluation indicates screening women aged 40-44 years results in 1.97 cancers detected per 1000 women, compared to 4.46 cancers detected in women 50-69 years.
“We know BreastScreen has been a highly successful program, and we know there are significant benefits to early detection. Excluding [older and younger] women would simply be a step backwards.”
But AMA president Dr Andrew Pesce says it’s important to remember these recommendations are just for the screening of asymptomatic women. “There is nothing to prevent women who feel a breast lump or who are concerned about an abnormality in their breast tissue from approaching their doctor for appropriate follow-up testing,” he says.
To ensure women understand this, he says the AMA would like to see women outside the target age group educated about why these strategies have been implemented and what to do when concerned about risk.
“You can’t just say to these younger or older women there is nothing we can do, especially when there are stories of young women with breast cancer all over the media... We have to address their concerns and allay their fears.”
Along with education, some have suggested the Federal Government provide Medicare rebates for GP examinations and, if necessary, a diagnostic mammogram. However, Associate Professor Liz Wylie disagrees.
Professor Wylie is chair of the Breast Imaging Reference Group at the Royal Australian and New Zealand College of Radiologists. She says there is no evidence to suggest breast self-examination or regular clinical examination reduces breast cancer mortality.
She cites a study of more than 200,000 women aged 50-79 years published only last month, which shows while clinical examination detects more cancers in women, it also leads to higher false-positive rates.3
“That would not be money well invested,” she adds.
Professor Wylie – like the AMA – is unfazed by the recommendation to exclude older and younger women.
“Only a very small number of women 40-44 years actually participate in the program. In fact, I think it would be around only 5% of the women screened.
“So, yes, the program would be withdrawing a service from a small group of women in whom there is no evidence screening significantly reduces mortality, and boosting resources to increase participation in women who do benefit.”
Professor Saunders also agrees with the recommendation to restrict the number of women screened.
“I truly believe what we need to do is get a lot smarter with breast cancer screening by trying to better identify those groups who need more screening and those who need less,” she says.
“This report has gone some way to finding the groups who need less screening, but there are other things we can look at.”
For example, she questions whether there is sufficient evidence to suggest women aged 45-50 should be screened annually and wonders if there is a better way of screening women at higher risk of breast cancer.
“Certainly there is some evidence that surveillance of women at very high risk due to their family history is useful, but I think that is probably best done in high-risk clinics,” she says.
“The problem we have at the moment is, how do we identify women at risk? Our screening program isn’t set up to do that... It is something that needs to be done by a doctor with training, and women don’t see a doctor when they come for a screening mammogram.”
While it is unclear whether these recommendations will be approved, Professor Wylie says in the current financial crisis, it is possible that some services will be reduced anyway.
“In particular, the recommendation to exclude women 40-44 years and 75 years and older,” she adds.
“I think, however, it will be difficult to find the substantial extra funding needed to expand the service in women 50-69 years.”
BreastScreen Australia: the facts
- The program targets women aged 50-69 years, but allows those aged 40-49 and 70 or older to attend
- 56% of women 50-69 years participate, and this is associated with a 21%-28% reduction in breast cancer mortality
- Women in very remote areas, Aboriginal and Torres Strait Islander women, and women who don’t speak English at home have significantly lower participation rates than the national average
- One out of five women recalled for assessment is not assessed within 28 days of a screen-detected abnormality
- Two out of five women do not return within two years for re-screening.
1. Australian Institute of Health and Welfare 2009. BreastScreen Australia monitoring report 2005-2006. Cancer series no. 48. Cat. no. CAN 44. Canberra: AIHW.
2. Australian Government Department of Health and Ageing. Evaluation of the BreastScreen Australia Program - Evaluation Final Report - June 2009.
3. Journal of the National Cancer Institute 2009;101:1236-43.