ASCO Breast: Pretreatment MRI Delays Treatment without Improving Outcomes
WASHINGTON, Sept. 8 (MedPage Today) -- Widespread use of breast MRI has led to treatment delays and was associated with an increased likelihood of mastectomy without improving outcomes, data presented here suggest.
A review of almost 600 breast cancer patients showed that MRI increased the odds ratio for mastectomy to 1.80 (P=0.01) compared with patients who did not have the imaging study, Richard J. Bleicher, M.D., of Fox Chase Cancer Center in Philadelphia, reported at the 2008 Breast Cancer Symposium.
Breast MRI delayed pre-treatment evaluation by more than three weeks and was associated with a 50% increase in the rate of positive surgical margins after lumpectomy.
"Breast MRI is used unpredictably and does not avoid positive margins or improve the rate of conversion from mastectomy to breast-conserving therapy," said Dr. Bleicher. "Without evidence that MRI decreases local recurrence after breast-conserving therapy, it should not be a routine part of patient evaluation for breast-conserving therapy."
More studies are needed to define the limitations of breast MRI, he added.
Breast MRI has a high sensitivity for cancer, revealing foci not seen with other imaging techniques in 10% to 30% of cases.
Studies have shown that MRI results often lead to changes in surgical planning, but little evidence indicates that the MRI-prompted changes improve breast cancer outcomes, the researchers noted.
"A subjective change in surgical plan cannot be equated with improvement in outcome," said Dr. Bleicher.
To clarify the impact of breast MRI on short-term outcomes in breast cancer, the investigators retrospectively reviewed records on all patients referred to the Fox Chase breast clinic from July 2004 through December 2006. The review identified 577 patients, 130 of whom had breast MRI evaluations.
All patients had a breast cancer diagnosis before referral, and 95.6% of breast MRI scans were performed before referral.
Each case was evaluated by radiology, pathology, surgical oncology, medical oncology, and radiation oncology.
The proportion of patients undergoing breast MRI increased from 13% in 2004 to 41.5% in 2005 and to 45.4% in 2006 (P=0.004), the investigators found.
The only factors associated with MRI use were age (more common in younger patients, P<0.001) and year of diagnosis (2005-2006 versus 2004, P=0.014, P=0.002).
Among patients who did not undergo MRI, the time from initial symptom to evaluation averaged 108 days, compared with 131 days when breast MRI was performed (P=0.011).
The time from diagnosis to first therapeutic surgery averaged 38 days without MRI and 57 days with MRI (P=0.010).
Mastectomy was the initial surgical procedure in 19.5% of patients who did not have MRI compared with 27.7% of those who did (P=0.024).
Among 290 patients who underwent breast-conserving therapy and final surgery type was known, 14% of those without MRI had positive surgical margins compared with 21.6% with MRI, a nonsignificant difference.
The rate of conversion from breast-conserving therapy to mastectomy was 5.9% without MRI and 9.8% with MRI (P=0.40).
"These results do not justify the routine use of MRI for the selection of local therapy," Dr. Bleicher said.
The study was supported by the U.S. Public Health Service and by the Commonwealth of Pennsylvania. Dr. Bleicher declared no conflicts of interest.
Primary source: 2008 Breast Cancer Symposium Source reference: Bleicher RJ, et al "The influence of routine pretreatment MRI on time to treatment, mastectomy rate and positive margins" ASCO Breast 2008; Abstract 227.
What breastcancer.org says about this article…
ASCO Breast: Pretreatment MRI Delays Treatment without Improving Outcomes
After breast cancer has been diagnosed, some doctors order a breast MRI (magnetic resonance imaging) to help them decide if mastectomy or lumpectomy should be recommended. The MRI is done to provide more information about the breast cancer, but there isn't good evidence that routinely using MRI in this way improves the doctor's recommendations, the care a woman receives, or the outcome of the treatment.
The study reviewed here found that an MRI after breast cancer diagnosis and before surgery didn't really help doctors make better decisions about whether mastectomy or lumpectomy was the best option for a woman. In this study, doing an MRI for more information led to a longer time between diagnosis and the start of treatment. The research was presented at the 2008 American Society of Clinical Oncology (ASCO) Breast Cancer Symposium.
The researchers analyzed the treatment records of 577 women between 2004 and 2006; 130 women had a breast MRI done before surgery. The results:
- MRI before surgery became more common over time. In 2004, 13% of the women had MRI, compared to 41.5% in 2005, and 45.4% in 2006.
- Getting an MRI before breast cancer surgery delayed surgery. Women who had an MRI had about 57 days (almost 2 months) between diagnosis and surgery. Women who didn't have MRI had 38 days (slightly more than a month) between diagnosis and surgery.
- Women who had an MRI before surgery were almost twice as likely as women who didn't get an MRI to have mastectomy instead of lumpectomy.
- Having a mastectomy because MRI was done before surgery didn't improve treatment results or the overall outcome compared to lumpectomy.
During lumpectomy, a pathologist looks at the edges (also known as margins) of the tumor that's removed to make sure they're "clear" (don't have cancer cells). If the tumor margins have cancer cells, more tissue may need to be removed or a mastectomy may need to be done.
If MRI before surgery were helping doctors make better choices about who should get a mastectomy vs. lumpectomy, then the researchers should have found that women who had MRI and lumpectomy were more likely to have clear margins. This wasn't the case. About 22% of the women who had MRI and lumpectomy had cancer cells in the tumor margins, compared to 14% of the women who had lumpectomy and didn't have MRI. Some of the women with cancer cells in the tumor margins had to have mastectomy to make sure all the cancer was removed. About 10% of the women who had MRI before surgery ended up having mastectomy instead of lumpectomy, compared to about 6% of the women who didn't have MRI.
These research results don't mean that having an MRI before surgery is a bad idea. The results suggest that ROUTINELY doing an MRI before surgery may not make sense; routinely doing MRI before surgery may lead to more mastectomy recommendations than lumpectomy recommendations with no improvement in care or outcomes.
If you've been diagnosed with breast cancer and your doctor recommends an MRI to help make choices about surgery, ask your doctor why MRI is being recommended and how the results will help your care.
You can learn much more about tests to evaluate breast cancer, including MRI, in the Breastcancer.org Screening and Testing section.
