As the diagnostic work-up for breast cancer has become more complex, often involving multiple imaging modalities, the surgeon-centered diagnostic paradigm in breast care has become less efficient. With the introduction of breast MRI into the diagnostic armamentarium, the need for a new radiologist-centered work-up became evident.
At Mercy Women’s Center in Oklahoma City, Oklahoma, our breast-MRI program began in 2002 with a breast coil on a body magnet. Within a very short time, preoperative breast MRI exposed unsuspected, more extensive multifocal, multicentric, and bilateral breast cancers that were virtually invisible using other modalities.
As I shared these findings with surgeons and the tumor board, and then with other facilities in the state, Mercy Women’s Center became a referral center for other breast centers in the region. Since new-diagnosis breast-cancer patients were considered priority cases, the three or four additional patients a day produced a backlog on the body MRI unit and bumped many of the brain, spine, and extremity MRI studies to an older MRI scanner on a regular basis.
It soon became apparent that we needed our own MRI system. We subsequently installed the only MRI designed specifically for breast imaging (with integrated breast computer-aided detection and biopsy capability) in our breast facility in 2003.
With the MRI system integrated into Mercy Women’s Center, the availability of MRI for our new-diagnosis breast-cancer patients was greatly improved, as was the option to use the MRI system for other indications (including high-risk screening and follow-up imaging for breast cancer, breast implants, and induction chemotherapy). As our procedural volume grew, I became increasingly aware of how much we were unable to see with mammography and breast ultrasound.
In fact, mammography and breast ultrasound are not that sensitive. In an article regarding screening for breast cancer, Elmore et al1 compared the sensitivity of mammography, ultrasound, and MRI, based on numerous published studies. They found that mammography’s sensitivity was 13% to 40%, with a mean of 33%; ultrasound’s sensitivity was 13% to 33%, with a mean of 33%; and breast MRI’s sensitivity was 77% to 100%, with a mode of 100%.
In 2002, the medical literature finally supported what those of us who do mammography already knew: Good mammography misses breast cancer in dense breasts. According to Kolb et al, 2 in dense breasts, the sensitivity of mammography is 48%, and this does not include comparison with breast MRI.
The more MRI studies I performed, the more aware I became that I was missing significant pathology on mammography and ultrasound. The question no longer was whether breast MRI was valuable, but how to select patients appropriately who really needed it, since the cost and technical expertise required to interpret breast MRI precluded performing it on everyone.
We now evaluate all new-diagnosis breast-cancer patients—as well as those with an atypical or discordant biopsy—with breast MRI. We evaluate patients with a past history of breast cancer about every two years. In addition, we contact patients with a greater than 20% to 25% lifetime risk of breast cancer and schedule them for annual breast MRI exams. We have found MRI invaluable in the work-up for those patients who have a new palpable mass with a negative mammogram and ultrasound, or multiple, probably benign masses in dense breasts.
In the past, many of those patients would have had multiple biopsies or would have gone to surgery. Instead, they have an MRI exam that accurately identifies those who have cancer and need intervention, and those who are truly negative. The remarkable occurrence is the number of times that the palpable concern is negative, but an occult malignancy is discovered elsewhere.
Within a very short time, it became clear that just interpreting the MRI exam and sending the report to the surgeon was unacceptable. Long ago, the surgeons had requested that we not contact them to obtain orders for work-up of their patients at our breast center; instead, we were asked just to do whatever imaging studies or procedures were indicated, in our professional opinions.
The surgeons expected the same from us regarding breast MRI. Therefore, if the patient had additional findings on the MRI, we took the responsibility of contacting the patient and conducting a work-up for the abnormalities, including the performance of any necessary biopsies.