News: One in seven cases of breast cancer are overdiagnoses, study finds

Roughly one in seven cases of screen-detected breast cancer are overdiagnoses, according to a study published in the Annals of Internal Medicine. The study focused on women aged 50 to 74 who were at average risk of breast cancer, finding 15.4% of those with screen-detected breast cancer were estimated overdiagnoses.

Of the overdiagnoses, 6.1% were due to the detection of indolent preclinical cancer. An additional 9.3% were due to “detecting progressive preclinical cancer in women who would have died of an unrelated cause before clinical diagnosis.”

Additionally, the study found overdiagnosis increased with age, with overdiagnosis of 11.5% at age 50 up to 23.6% at age 74.

“This information clarified the risk for breast cancer overdiagnosis in contemporary screening practice and should facilitate shared and informed decision making about mammography screening,” the study notes.

Editor’s note: The Annals of Internal Medicine published study can be found here.