Scientists are reporting in a new study that mammography is not an effective screening tool for women in their 40s because a tumor and the patient's tissue appear to be the same color.
Stanford University researchers reporting in Tuesday's Journal of the National Cancer Institute said while the screening technique works best for women over 50, the denser tissue of younger women tends to obscure tumors.
For years, doctors have known that tumors and dense tissue tend to appear white on a mammogram. In women who have undergone menopause, breast tissue often appears gray on a mammogram, so the sharp color contrast of the tumor is not as difficult to miss.
The researchers used an assessment technique called the Breast Cancer Screening Simulator to create hypothetical screening scenarios whereby they could estimate the median tumor size detectable on a mammogram and the tumor growth rate in women in two groups: those aged 40 to 49 and 50 to 69. The technique, based on medical data, revealed that tumors grow faster in younger women and are more difficult to detect.
"It's true that these younger patients have denser breasts and tumors can hide," said Dr. Rajiv Datta, medical director of the cancer center at South Nassau Communities Hospital in Oceanside. "You get a whiteout effect. . . . We never rely on mammography alone," he said. "We take a detailed family history of younger women and also conduct other testing."
Alternate imaging can help doctors discern the presence of a tumor when mammograms leave questionable results, Datta said. Sonograms are a secondary form of testing for younger women. No form of screening is perfect, Datta added, which is why physicians increasingly turn to multiple methods of assessment.
"We are in a situation now where we are trying to balance the use of technology as we try to learn more about the life cycle of cancer."