Victor J. Zannis, MD, FACS

The use of preoperative breast MRI for newly diagnosed breast cancer patients remains a complex and controversial topic in the breast cancer community. Supporters of the routine use of MRI argue that it improves surgical planning, reduces re-excision rates and lowers the risk of recurrence – all of which could lead to an improvement in overall survival rates.

Opponents, on the other hand, point out that these benefits have not been demonstrated in the available data. In addition to the lack of evidence that MRI improves survival, they argue that the higher cost, additional biopsies, increased patient anxiety, and the potential link between MRI and unnecessary mastectomies are sufficient justification to use the modality sparingly.

Breast surgeon Victor J. Zannis, MD, FACS discusses this controversial topic, including how he utilizes MRI in his own practice and the role it should play in the patient selection process for accelerated partial breast irradiation (APBI).

How often do you recommend preoperative breast MRI for your newly diagnosed breast cancer patients?

I individualize the use of breast MRI, obtaining one in about 30-40% of my newly-diagnosed breast cancer patients.

How do you determine which patients will benefit from an MRI as part of the breast cancer treatment planning process?

I selectively use preoperative MRI in 1) younger patients with dense breasts, for which mammography and ultrasound have less sensitivity, 2) patients with significant family history of breast cancer, or those who are already known BRCA gene carriers, because their risk of second cancers is elevated, and 3) those patients whose breast physical exam or imaging has complexity, so-called “busy-breast-syndrome”.

What are the risks of relying on MRI for breast cancer diagnosis and surgical planning?

In spite of breast MRI being the most sensitive imaging test for breast cancer, the routine use of preoperative breast MRI remains controversial because the data from studies is conflicting. For example, breast MRI has not been shown to provide a survival benefit, and there are also commonly false-positive results that lead to more biopsies, more patient anxiety, and probably more unnecessary mastectomies. Also, finding secondary occult breast cancers with breast MRI intuitively seems valuable, but the actual benefit of finding these possibly harmless lesions is still unproven. Additionally, measuring the extent of breast disease in the breast with MRI can be helpful; however, MRI may at times overestimate this, particularly following needle biopsy, which may again lead to unnecessary anxiety and mastectomies.

Is the use of preoperative MRI leading to unnecessary mastectomies in women who would otherwise be suitable candidates for breast conservation therapy?

We are now seeing the proportional mastectomy rate for breast cancer therapy increasing in recent years. Several studies have suggested that the increased use of breast MRI accounts for at least some of this increase. To obviate this problem, it is imperative that histological proof of cancer in any additional suspicious areas in the breast be obtained before a mastectomy is deemed necessary.

One study (Bilimoria et al., Arch Surg) found breast MRI resulted in a beneficial change in surgical management in only 9.7 percent of newly diagnosed breast cancers – is this a significant enough impact to justify the use of MRI despite its limitations (i.e. high false positives, low specificity)?

There is no easy answer to that question – we debate that answer vigorously, sometimes for hours, at our national meetings.

Personally, since MRI overestimates the disease so frequently, I rarely rely on MRI-determined extent of disease to dictate the surgery I perform. I would rather perform a smaller surgical procedure and allow the histology of the tissue obtained, including margin-assessment, to decide whether further surgery is necessary. I feel like I conserve many more breasts that way.

What role should MRI play in the patient selection process for APBI?

Again, this is debated. It would seem intuitive once again that it is imperative to find occult elsewhere-in-the breast second cancers with MRI, particularly if focused postoperative irradiation like APBI is used, rather than whole breast. However, studies have shown that 1) in-breast recurrences are nearly always in the lumpectomy cavity margins, not elsewhere, 2) that whole breast irradiation does not prevent elsewhere-in-the-breast recurrences, and 3) patients treated with APBI who did not have MRI as a part of their workup had as few recurrences as comparable cohorts of patients treated with whole breast irradiation.

Dr. Victor Zannis is a board certified surgeon and medical director of the Breast Care Center of the Southwest in Phoenix, Arizona. He has performed breast surgery for more than 25 years and, for the last 12, has subspecialized full-time in breast care. Dr. Zannis has served as President of the Southwestern Surgical Congress and has also been President and is now Chairman of the Board of The American Society of Breast Surgeons.