Breast Cancer not Always Found With Mammogram

Kathleen Blanchard's picture

A Dartmouth study found that patients with breast cancer had additional breast cancer tumors that were not found on mammogram or ultrasound. Undetected breast cancer tumors were discovered using MRI (magnetic resonance imaging) in twenty-percent of women.

Sixteen percent of women had more breast cancer tumors than identified on mammogram. Four percent had tumors in the opposite breast, leading to recognition of possible shortcomings of mammogram and ultrasound for breast cancer detection.


Petra J. Lewis, MD, lead author of the study says, “These patients had already had bilateral mammography and these tumors had not been apparent on mammography.” In 199 patients diagnosed with breast cancer, mammogram failed to detect tumors in the same breast, and did not find tumors in the opposite breast.

Dr. Lewis says the findings that breast cancer tumors are not found in such a significant number of women who have mammograms are important for the survival of women with breast cancer.

“The detection of an unsuspected tumor is critical. These additional tumors in nearly a fifth of patients are tumors that can potentially grow and not be diagnosed until they are much larger - affecting the health and survival of the patients.” Dr. Lewis recommends that clinicians discuss recommendations for MRI for finding breast cancer tumors not found with mammogram. The study shows that not all breast cancer if found with mammogram and ultrasound.