With new 3-D technology, the number of false alarms and call-backs may be reduced
Getting called back after a mammogram is actually quite common, and according to the American Cancer Society fewer than one in ten of these instances results in cancer being found.
After your first mammogram, especially, call-backs are normal as doctors have no previous images and will want additional ones with which to make comparisons. A call-back is also more common for women who have not gone through menopause.
But try telling this to any woman who gets the call.
No amount of evidence will convince you. No words of reassurance (“We just want a second look”) will calm you. It’s a scary moment. It’s human nature.
In addition to the anxiety they create, call-backs and false alarms are also inconvenient (you may need to arrange for time off work) and they also represent a significant cost to the health care system.
This is why one of the more recent breakthroughs in breast cancer detection is so exciting.
A new 3-D based technology called tomosynthesis is able to see through denser breast tissue, which has long been a challenge for traditional 2-D, x-ray based mammography. This more accurate 3-D imaging not only means improved (and earlier) detection, it may also means fewer false alarms, and fewer of those stress inducing call-backs.
Why do “false alarms” happen?
With traditional 2-D mammography, which produces a flat picture, areas of normal breast tissue may look suspicious because on a flat image these areas can appear on top of each other, which may create the appearance of an anomaly in an area where in fact there is none. This lack of clarity is enough for doctors to call you back in for a closer look.
The 3-D imagery of tomosynthesis, however, is created using multiple x-rays which are taken at multiple angles, and the 3-D image that is assembled from these x-ray images enables doctors to see an area from multiple viewpoints, thus removing the layering effect we get with the 2-D model.
A commonly used adage illustrates the benefits of 3-D even more: 2-D is a circle; 3-D is a ball.
Early results with digital tomosynthesis are promising. Currently there is an international multi-site prospective research trial (T-MIST), which includes three Canadian sites, to determine if tomosynthesis is better than traditional 2-D mammography at finding the sort of breast cancers that are most likely to spread and kill women.