A wide-ranging, long-term study has cast doubt on the value of annual breast X-rays—and sparked fierce debate in the medical world. The study of 90,000 Canadian women over 25 years suggests annual mammograms could be useless or possibly worse than useless: the death rate from breast cancer and from all causes was the same among women aged 40 to 59 who had annual mammograms and those who had only a physical exam, the CBC reports. More than a fifth of cancers found by mammograms were not a threat to the woman's health, but the "overdiagnosis" caused them to have unnecessary treatments like chemotherapy, the study says.
The researchers say policymakers should reconsider the need for mammograms, arguing that new treatments and better awareness of breast cancer make it less vital to catch cancers so early, the New York Times reports. But some experts and groups not involved in the study disagree strongly with its conclusions and argue that one study—no matter how extensive—shouldn't be cause to change public health policy, the Los Angeles Times finds. The American College of Radiology called the study "deeply flawed" and "incredibly misleading," arguing that it involved "second-hand" mammography equipment and poorly trained technicians.