What are the limitations of screening mammography?
• Finding cancer does not always mean saving lives: Even though mammograms can detect tumors that cannot be felt, finding a small tumor does not always mean that a woman’s life will be saved. Screening mammograms may not help a woman with a fast-growing or aggressive cancer that has already spread to other parts of her body before being detected. • False negatives: False negatives occur when mammograms appear normal even though breast cancer is present. Overall, screening mammograms miss 10 to 25 percent of the breast cancers that are present at the time of screening. False negatives occur more often in younger women than in older women because the dense breasts of younger women make breast cancers more difficult to detect in mammograms. As women age, their breasts usually become more fatty (therefore, less dense), and breast cancers become easier to detect with screening mammograms. • False positives: False positives occur when radiologists decide mammograms are abnormal, but no cance
