Breast cancer screening ‘doesn’t make much of a difference’ to death rates, says oncologist

Ireland should screen women for the disease on the basis of risk not age, says expert

Mammogram: Breast cancer is the most common cancer in Irish women, with about 3,500 cases and more than 700 deaths a year. Photograph: iStock
Mammogram: Breast cancer is the most common cancer in Irish women, with about 3,500 cases and more than 700 deaths a year. Photograph: iStock

Screening women for breast cancer “doesn’t make much of a difference” to death rates from the disease, according to a leading breast cancer specialist.

The benefit originally shown for breast cancer screening has been “abrogated” by improvements in the treatment of the disease over the past 50 years, according to Prof John Kennedy, clinical professor of oncology at Trinity College Dublin.

“I believe screening doesn’t make much of a difference to death rates from breast cancer,” Prof Kennedy told a conference in Dublin. “We screen based on age because we’re able to, we don’t screen based on risk, which is what we should be doing. If there was a very low risk, there probably is very little benefit to screening.”

Internationally, death rates from breast cancer have tumbled in recent decades. But they have also fallen in Switzerland, added Prof Kennedy, which does not have a national screening programme.

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Irish women aged between 50 and 69 are eligible for a mammogram (breast X-ray) every two years under BreastCheck, the State’s national breast screening programme. There are plans to expand the age range to 45-74 years.

“The scale of the benefits of population-based breast screening has always been the subject of scientific debate, which is the reason why the benefits and harms of screening need to be spoken of clearly and transparently, including the risk of overdiagnosis,” a spokeswoman for BreastCheck told The Irish Times. “Age is considered the biggest risk factor in breast cancer.”

Breast cancer is the most common cancer in Irish women, with about 3,500 cases and more than 700 deaths a year. Approximately one-third of cases are diagnosed through breast screening.

Overall survival rates for all cancers have increased by 40 per cent since the 1980s but getting further improvements will prove difficult, because “the low-hanging fruit has already been plucked,” Prof Kennedy said.

And while Ireland’s performance has improved, “our services were so bad in 1996 that it was not hard to make them better”.

Most of this improvement in outcomes is due to employing nurse and surgical specialists, better radiology that provides more information about the location of cancers and the creation of centres of excellence or, in Ireland, “centres of adequacy”, he told the conference organised by the National Centre for Pharmacoeconomics.

Survival rates in Ireland are better where services are centralised, as they are for breast, oesophageal and pancreatic cancers — and worse where they are not — such as with gynaecological cancers, he said.

To make further improvements, clinical trials should be focussed on areas with the greatest need, clinical research should be made a core activity in hospitals and studies need to be simplified.

“We hire consultants back from the US with stellar reputations and we don’t provide them with the capacity they need to continue their research careers,” he said.

The pharmaceutical industry has become “pathologically risk averse” and addicted to regulation over the past 10 years “to the detriment of getting anything”, he added.

Paul Cullen

Paul Cullen

Paul Cullen is a former heath editor of The Irish Times.