March initiated what could be a sea change in the diagnosis of breast cancer in high-risk women, with results of a breast MR study published in the New England Journal of Medicine and, in the same week, new guidelines issued from the American Cancer Society (ACS) that recommended breast MR as a screening tool for high-risk women.
The breast MRI trial, conducted by the American College of Radiology Imaging Network (ACRIN) and financed by the National Institutes of Health, evaluated the effectiveness of using breast MRI of the contralateral breast in 969 women with recently diagnosed breast cancer. MRI detected clinically and mammographically occult breast cancer in the contralateral breast in 30 of 969 women who were enrolled in the study (3.1%). All participants underwent dynamic contrast-enhanced breast MRI on a 1.5T or greater magnet. Biopsy was performed in 121 of the 969 women (12.5%), and 30 of the specimens were positive for cancer (24.8%); 18 of the 30 specimens were positive for invasive cancer. The mean diameter of the invasive tumors detected was 10.9 mm.
Participating imaging sites included both academic institutions and private practices. ImagingBiz.com recently spoke with one of the study’s 13 co-authors, Daniel D. Maki, MD, representing the 42-physician practice Scottsdale Medical Imaging Ltd, Scottsdale, Ariz. Maki, fellowship trained in MRI and thoracic imaging and ACRIN Trial 6667 coordinator for SMIL, discussed the implications of both the study and the new ACS guidelines for patients and the imaging center business. He also commented on the value of private practice participation in ACRIN studies.
ImagingBiz.com: What are the implications of the study for patients?
MAKI: The implication of the study is that breast MR is extremely sensitive for the detection of cancers in the opposite breast in patients who have been diagnosed with breast cancer. It showed a large increased yield in detection of cancers over mammography and physical exam alone. Traditionally, about 3% of those patients diagnosed with breast cancer in one breast were found to have cancers in the opposite breast coincidentally with physical exam and mammography. Well, breast MRI finds an additional 3.1% so it’s about a 100% increased yield in the cancer detection over physical exam and mammography, which is pretty significant.
ImagingBiz.com: What does this imply for imaging centers?
MAKI: The implication for imaging centers is that there is the potential for a lot more breast MR to be performed. In this study, we primarily looked at imaging of the opposite breast, but one could infer from the results that breast MRI is extremely sensitive and accurate and can be used in the cancer breast as well, which is already being done in many places around the country, including at SMIL. When you look at both accurately staging the initial tumor as well as staging the opposite breast, I think the potential is for a large increase in utilization of breast MR over the next few years. In an ancillary note, the American Cancer Society came out with the new guidelines that recommend breast MR annually as a screening tool in patients who are very high-risk for breast cancer. And that made big news nationally, as well, and that will also increase utilization. These are patients who don’t even have the cancer, these are patients who carry the genes or have very strong family history. In these patients it will be used potentially as a screening tool.
ImagingBiz.com: Are there any special technical challenges in performing breast MRI?
MAKI: Several things. Number one, breast MR is not like doing an MR of the knee or shoulder in that you can put somebody in and even if you don’t do a perfect job, you’ll get a diagnostic study. To the contrary, there are some very strict guidelines to be followed. You have to have contrast and the scans have to be performed at certain intervals following contrast, and if your time intervals are off or your injections are off, it will be a non-diagnostic study. In addition, it needs to be performed on a specialized breast coil in order to get really high-resolution images, it can’t just be done in a body coil. There are some well-published guidelines on how to do them correctly, and we also described our protocol in the study. Places that try to do breast MR haphazardly, not injecting the contrast dynamically, not performing the scans at the appropriate time intervals, and not using the high resolution specialized breast