Breast MRI develops role as surgical planning tool

The use of breast MRI prior to surgery is still relatively novel, with clinical guidelines yet to be established and research studies still under way to validate its clinical efficacy. But as sites develop their own approaches to patient selection and usage, anecdotal evidence indicates that breast MRI is making a difference.

“[Breast MRI] alters our treatment plan about
one in five times.
We think it's helpful in
making decisions.” — Dr. Stephen Grobmyer,
University of Florida, Gainesville, FL

The University of Florida in Gainesville began using breast MRI three years ago to plan breast surgery, coinciding with the capability to do MRI biopsies at the medical center. MRI has value in better estimating tumor size, according to a study published in the Journal of the American College of Surgeons in May 2008 by a research team including Dr. Stephen Grobmyer, a surgeon in the division of oncology and endocrine surgery at the university.

"It helps us find spots of multicentric disease and ... to identify a small subset of patients in whom there is occult cancer in their contralateral side," Grobmyer said. "That combination of findings ... alters our treatment plan about one in five times. We think it's helpful in making decisions."

Grobmyer emphasizes that research is still ongoing, and there are no firm national recommendations for using breast MRI in a surgical planning role, but an evolution is under way. He sees MRI reducing the rate of margin-positive excision because it allows surgeons to plan operations better. It also allows specialists to better select patients for breast conservation and those patients who should receive preoperative chemotherapy for larger lesions to get tumor shrinkage and allow clear resection. "We are strong advocates for having the ability to do MR-directed biopsies if you're going to have a program in MR," Grobmyer said. "With ... the ability to do breast MR-guided biopsies, you can work up a lot of these lesions that you don't know about."

One case at the center involved a woman in her 40s who presented with a lesion in the right breast. The patient had stereotactic biopsy that showed invasive lobular cancer. She was contemplating breast conservation, so a breast MRI was performed on her bilateral breast. The MRI study showed the index lesion on the right side and also a previously undetected 1-cm invasive ductal cancer on the left side. Breast conservation was achieved in that case.

"There's just case after case of this," Grobmyer said. "It's not every case; it's only one in five that we find it, but we think that the patients we find it in are most appreciative of that early detection."

If a woman is going to choose mastectomy for a localized, small lesion, Grobmyer said the benefit of MRI is reduced, although there is a 3% to 4% chance of finding a contralateral occult lesion. In a younger person who is considering breast conservation, an MRI is more likely ordered because the information acquired by MRI produces more value in this population. Generally, for older patients with small, well-differentiated breast cancers, the prognosis is excellent so there is less rationale for ordering the study.

"The younger patients with more time at risk and more time to live are more likely to develop recurrence of problems, so they might receive most benefit from this procedure," Grobmyer said.

But Grobmyer noted that there are still no national guidelines regarding using breast MRI as a preoperative surgical tool.

"The use of breast MRI as a broad recommendation in the preoperative setting is not well-established by any professional group on any side that I am aware of," he said. "If it is going to be used, it needs to be done in the proper setting."

Mastectomy versus breast conservation

Although a Mayo Clinic study published in May 2008 of 5,464 women with early-stage breast cancer between 1997 and 2006 found that women who get MRI studies are more likely to choose mastectomies, Mercy Women's Center in Oklahoma City is seeing the opposite occur.

Breast MRI studies at Mercy are resulting in decisions to choose breast conservation as well, resulting in a net gain in lumpectomy patients. Mercy's overall conservation rate is higher now than before it started the MRI program. Their research findings have been accepted by the American Journal of Surgery and will be appearing soon.

“One of the ways we quantified [breast MRI's effectiveness] was how often people had to go back to the operating room for an unsuccessful lumpectomy. Our reincision rate was 8.8%. The average reincision rate is
about 25%.” — Dr. Alan Hollingsworth,
Mercy Women's Center, Oklahoma City

"We are converting some to mastectomy, but it's an appropriate conversion," said Dr. Alan Hollingsworth, medical director at Mercy. "When there's tumor beyond the ability of neoadjuvant chemotherapy, sometimes mastectomy is more appropriate. We think we have more people who were contemplating mastectomy, that, once they see they have just a solitary focus, they're going with breast conservation."

Mercy Women's Center also has a breast radiation program that requires preoperative breast MRI. Patients who have the assurance of no other area of cancer in the same breast are candidates for the partial-breast radiation program.

Using a blanket approach for breast MRI, the center found opposite cancers in 3.7% of patients -- disease that was missed by mammography. Of 597 patients in which MRI alone found 22 additional patients with cancer, 15 were invasive, significant cancer and seven were in situ. That equates to large numbers of patients who would go untreated without breast MRI.

MRI studies are most useful in younger patients with dense breast tissue and those with invasive lobular cancer, which tends to permeate breast tissue and not form a well-defined mass. However, other findings showed older patients with low-density mammograms who had abnormal areas on their MRI study.

Of the patients who had preoperative MRI and were initially thought to be good lumpectomy candidates, Hollingsworth said almost 8% had more tumor than was anticipated -- so much more it looked as though mastectomy might be necessary. Half of those were completely separate tumors than the primary.

Breast MRI showed more tumor at the site of the index lesion than was sometimes realized with mammography or ultrasound. The larger extent of disease at the tumor site allows the surgeon to plan a wider excision.

"One of the ways we quantified it was how often people had to go back to the operating room for an unsuccessful lumpectomy," Hollingsworth said. "Our reincision rate was 8.8%. This [was] out of [approximately] 600 patients. People are surprised to know that the average reincision rate is about 25%."

By creating a road map for preoperative staging and doing a better job up front, MRI creates a cost savings.

A comprehensive approach

In performing oncoplastic surgery, Dr. Gail Lebovic of the Cooper Clinic in McKinney, TX, uses breast MRI on all newly diagnosed patients and for annual follow-up of cancer patients. Lebovic attempts to preserve as much of the breast tissue or skin as possible, and breast MRI helps evaluate fully the woman's clinical situation.

In one case, a 64-year-old woman was referred to the clinic for a wire-localized biopsy following an abnormal mammogram in the right breast and a stereotactic biopsy that was nondiagnostic but showed atypical cells.

“Had we not had the MRI, [the patient] would have had the biopsy in the right breast, then a year later [she] would have gone for her mammogram, and the left side might have had invasive [cancer].” — Dr. Gail Lebovic,
Cooper Clinic, McKinney, TX

Many surgeons might have prepared the patient for surgery, performed the wire-localized biopsy, found a small area of ductal carcinoma in situ (DCIS), and would have been done. Instead, Lebovic and her colleagues viewed all the woman's films and were concerned about her left breast calcifications. With breast MRI, they were able to see DCIS throughout her entire left breast.

"Had we not had the MRI, she would have had the biopsy in the right breast, then a year later [she] would have gone for her mammogram, and the left side might have had invasive [cancer] at that time," Lebovic said. "But we caught it before she had any invasion."

Looking at the breast in three dimensions with MRI helps surgeons evaluate patients in the same 3D environment they work in. As a result, planning is much more thorough and the surgery more complete. The ability to rotate images helps surgeons get a feel for tumors and surrounding tissue.

Breast MRI is also used for women who are found to have a positive lymph node without any indication by mammogram or ultrasound. In addition to locating a lesion, if a tumor is invading the chest wall or skin, MRI can help provide a more thorough evaluation of the tumor before surgery goes into the chest wall, which helps avoid additional surgeries for positive margins.

By incorporating preoperative breast MRI into the surgical plan, treatment options become complete, which is better for patients.

Moving forward

Breast MRI adds value not only in ensuring the best surgical procedure the first time, but also in postoperative follow-up.

“I think that broader indication will come if technology improves so that we can more accurately, more specifically diagnose cancers with MRI.” — Dr. Margaret Lawler,
Faulkner Breast Centre, Boston

"As time goes on, if a woman has partial mastectomy and radiation, if there are questions over areas of thickening or some concern over scar tissue, and it becomes evident that an MRI might be helpful in working that up, an MRI is done," said Dr. Margaret Lawler, a breast surgeon at the Faulkner Breast Centre in Boston.

"And as the technology improves, it will be more broadly used.

"It would be terrific if we could use MRI to assess margins and to accurately assess extensive disease," Lawler said. "I think that broader indication will come if technology improves so that we can more accurately, more specifically diagnose cancers with MRI."

Despite resistance by some experts to use breast MRI as a standard test prior to surgery, the technology's growth is evident.

"Medical literature studies have shown that [breast MRI] can change the surgical technique in ways that one would feel, at least intuitively, may be beneficial," Lawler said.

By Lin Muschlitz
AuntMinnie.com staff writer
September 2, 2008

Copyright © 2008 AuntMinnie.com