Screening can halve the chance of breast cancer death: study

The case for regular breast screening has been strengthened by a study including 4,000 Australian women. AAP

Breast screening can help women halve their risk of dying from breast cancer, a new Australian study has found.

The research, published today in Cancer Epidemiology, Biomarkers and Prevention, is the largest of its kind in Australia, including almost 4,000 women from Western Australia aged 50-69 years.

“It’s a really solid finding, not just in Australia, but globally,” said Carolyn Nickson, who conducted the study together with colleagues from the University of Melbourne’s School of Population and Health.

The study included 427 cases where women had died from breast cancer and 3,650 control women who were still alive when the other women died.

The researchers also undertook a meta-analysis of similar studies, showing an average estimate of a 49% reduced risk of dying.

Dr Nickson said she hoped the findings helped people to move on from the debate about whether screening reduces mortality to focusing on how to improve the program for women who choose to participate.

“It certainly presents evidence that the breast screening program as it has been in place for the last 20 years should continue. It’s definitely a worthwhile program,” Dr Nickson said.

The study comes after Queensland Health Minister Lawrence Springborg was forced to issue a statement assuring the future of BreastScreen Qld following a decision to restructure the organisation.

Some previous studies have shown that although breast screening may reduce a woman’s chance of dying from breast cancer, it also causes major harms.

Dr Nickson and her colleagues write in their paper that while a recently published European ecological study found no mortality benefit from screening, it paid little heed to numerous contrary results from randomised trials and previous observational studies.

However Robin Bell, deputy director of the Women’s Health Program at Monash University’s School of Public Health and Preventive Medicine, said the study’s case controlled design meant it was hard to eliminate bias.

“Say if not going to screening was also linked to not taking your medication, then women who died of breast cancer would look like they weren’t screened, but also died because they didn’t take treatment,” Professor Bell said.

She added that the study doesn’t address the issue of overdiagnosis at all, which is a problem given the harm that can occur as a result.

“If you’ve got an uncertain amount of benefit and at least a minimum amount of harm then you’ve got an enormous amount of responsibility when it comes to advising women.”

Professor Bell said while she couldn’t say there was no benefit from screening, inviting healthy people to do something meant there was a responsibility to make sure that the balance of benefits and harms was very favourable.

Dr Nickson acknowledged the issue of overdiagnosis, but said focusing on tailoring treatment appropriately was the best thing that could be done to address the problem.

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