Facing a barrage of inquiries from concerned patients, the association representing Quebec radiologists is defending a provincial decision to keep using mammography machines that Ontario is scrapping.
The president of the Association des radiologistes du Québec, André Constantin, acknowledged that radiologists across the province have been fielding calls from women since news of a study suggesting the machines were inferior to other screening devices broke in The Globe and Mail on Tuesday. But he said that following Ontario's approach of replacing the equipment and encouraging women to be retested would be "overreacting" and "excessive."
He added, though, that the province would retroactively examine the detection rates for the machines and use the data to plan the best course of action. A spokeswoman for Health Minister Réjean Hébert could not immediately confirm such an initiative.
Meanwhile, a Health Canada spokesman said on Wednesday the agency is weighing the results of the study, conducted by Cancer Care Ontario and published this week, and has no plans to prohibit the use of the machines.
The units at issue use a digital technology called computed radiography, or CR. It is the primary means of detecting breast cancer in Quebec, accounting for three-quarters of the province's 144 mammography machines. About a quarter of Ontario's machines use CR.
The remaining machines either employ traditional screen-film technology, which produces black-and-white X-ray images, or a form of digital technology called direct radiography, both of which were found in the study to be more effective at detecting tumours than CR. The study analyzed 816,000 mammograms carried out on 688,000 women aged 50 to 74 in Ontario.
Citing data that showed Quebec's detection rate to be stable over the past 10 years and comparable to that of Ontario, Dr. Constantin said the study should be taken "very seriously" but that there is no reason for alarm.
For every 1,000 women screened in Quebec, cancer would be found in five of them, he said. According to the study, DR and screen-film mammograms in Ontario identified 4.8 or 4.9 cancers per 1,000, while CR technology found just 3.4 cancers per 1,000.
"We're going to go back in time and look for a difference in detection," Dr. Constantin said. "Right now, the fact that the detection rate is stable and has been stable through the use of CR and DR technology [in Quebec], that's reassuring and it'll give us time to look at the data."
Martin Yaffe, a senior scientist in the imaging research program at Sunnybrook Health Sciences Centre in Toronto and a co-author of the study, called Ontario's $25-million move to replace the province's 76 CR machines "the right step."
"I don't think it's reason to panic, but I do think that we know we can do a better job if we use DR or film," Dr. Yaffe said. "If you're looking at the screening program, the conclusion is we should be phasing out CR."
Health Canada spokesman Sean Upton said previous assessments of CR machines by the Canadian Agency for Drugs and Technologies in Health did not suggest they were an inferior product.
"Mammography screening using either CR, DR or film systems has been shown to save lives," Mr. Upton said.
"Health Canada will continue to monitor new research development in this area and will use that information to guide further assessments of the effectiveness of CR technology."