One in three women with breast cancer detected by a mammogram are treated unnecessarily, according to a Danish study published Monday in Annals of Internal Medicine, which has renewed debate over the value of early detection.
The women didn’t need treatment, researchers write, because they had tumors so slow-growing that they’re essentially harmless.
The study raises the uncomfortable possibility that some women who believe their lives were saved by mammograms were actually harmed by cancer screenings that led to surgery, radiation and even chemotherapy that they didn’t need, said Dr. Otis Brawley, chief medical officer of the American Cancer Society, who wrote an accompanying editorial but was not involved in the study.
Researchers increasingly recognize that not all breast cancers pose the same risk, even if they look the same under a microscope, Brawley said. While some early tumors turn into deadly monsters, others stop growing or even shrink. But assuming that all small breast lesions have the potential to turn deadly is akin to “racial profiling,” Brawley wrote in his editorial.