February 19, 2010 — Magnetic resonance imaging (MRI) did not reduce the need for repeat operation within 6 months in breast cancer patients scheduled for wide local excision and might not be necessary in that population, according to data from the Comparative Effectiveness of MR Imaging in Breast Cancer (COMICE) trial.
The study, published in the February 13 issue of The Lancet, was led by Lindsay Turnbull, MD, from the Centre for Magnetic Resonance Investigations at the University of Hull and Hull Royal Infirmary in the United Kingdom.
The researchers found that the proportion of breast cancer patients needing reoperation was exactly the same (19%), regardless of whether or not MRI was added to standard triple assessment with clinical examination, x-ray mammography and/or ultrasound imaging, and fine-needle aspiration cytology or core biopsy.
In an accompanying editorial, Elizabeth A. Morris, MD, argues that despite the COMICE data, "it is too early to completely dispense with preoperative breast MRI."
Dr. Morris, from the Department of Radiology at Memorial Sloan-Kettering Cancer Center and the Department of Radiology at Weill Cornell Medical College in New York City, notes that at Memorial Sloan-Kettering, breast-conserving surgery is designed to remove the smallest volume of tissue possible and is associated with re-excision rates "closer to 25%."
"With the extremely wide negative margins in COMICE [0.5 to 5.0 mm for invasive disease; 1.0 to 10.0 mm for ductal carcinoma in situ], MRI might have little to add in mapping the area of tumor in this population. With smaller resection volumes with higher re-excision rates, the benefit of using MRI might well be greater," Dr. Morris writes.
Dr. Morris also notes that COMICE provides no information about the effect of MRI on outcomes other than reoperation rates.
"COMICE does not fully answer whether preoperative breast MRI adds benefit because recurrence and overall survival were not examined. COMICE was designed only to look at reoperation rate. It is a shame that no recurrence data will be obtained," Dr. Morris writes.
Outcomes and Economics
The COMICE trial was inspired by observational studies showing greater accuracy for MRI than for x-ray mammography or ultrasound (J Clin Oncol. 1999;17:110-119). COMICE was conducted in 45 British centers, recruiting 1623 women 18 years or older with biopsy-proven primary breast cancer who were scheduled for wide local excision.
Patients were randomly assigned to receive either MRI (n = 816) or no further imaging (n = 807). The primary end point was the proportion of patients undergoing a repeat operation or further mastectomy within 6 months of randomization or the number who were found to have had a pathologically avoidable mastectomy at initial operation.
The researchers found that the addition of MRI to conventional triple assessment did not reduce the reoperation rate, which was 153 of 816 in the MRI group and 156 of 807 in the no-MRI group.
The researchers also found no differences in health-related quality of life between the groups 12 months after initial surgery, and no significant difference in costs ($8877.36 per MRI patient vs $8402.10 per non-MRI patient; P = .075).
The clinical outcomes and economics do amount to a good value, suggest the authors.
"In view of the similar clinical and health-related quality-of-life outcomes of patients in both groups, we conclude that the addition of MRI to the conventional triple assessment might result in extra use of resources at the initial surgery period, with few or no benefits to saving resources or health outcomes, and the additional burden on patients to attend extra hospital visits."
However, Dr. Morris also raises the question of the value of MRI in the early detection of cancer in the contralateral breast prior to breast-conservation surgery.
"For the contralateral breast, COMICE showed a cancer detection rate of 1.6% (13 of 816), which is slightly below that of other multicenter trials. (N Engl J Med. 2007;356:1295-1303). This difference might be due to a real difference in the incidence of contralateral disease in this population, or might reflect issues with the quality of imaging and interpretation. Whatever the reason for this difference, a strong argument exists for early detection of contralateral disease, which can lead to simultaneous treatment of synchronous cancers rather than multiple treatments on separate occasions," Dr. Morris says.
Just why the better tumor visualization possible with MRI did not translate into reduced reoperation rates and improved outcomes is an open question.
One possibility raised by the COMICE researchers involves a disconnect in the way imaging is done and the information surgeons need. They point out that all imaging is currently done with the breast cancer patient in a different position than that assumed during surgery.
Dr. Turnbull and Dr. Morris have disclosed no relevant financial relationships.
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