24 September 2015
It is not uncommon that after a breast cancer diagnosis, a breast MRI is recommended. We know that there are limitations to mammography – it might not show everything of concern, especially in women with dense breast tissue. The idea behind preoperative MRI is that if there are other lesions, better to know about them and determine if they are cancerous or not, before going to surgery. This should lead to better surgical outcomes. Makes sense.
The problem is, studies have not been able to show a benefit to preoperative MRI. This was addressed in a recent issue of JAMA Oncology. Dr. Angel Arnaout and colleagues reported on the Use of Preoperative Magnetic Resonance Imaging for Breast Cancer: A Canadian Population-Based Study. In this retrospective population-based study, 53,015 patients with operable (early-stage) breast cancer were identified between 2003-2012.
Overall, close to 15% of patients underwent an MRI, and the use increased from 3% to 24% during the 10 year period.
Patients undergoing a preoperative MRI were more likely to be younger, of higher socioeconomic status, cared for in teaching hospitals, being cared for surgeons with a high volume of breast cancer cases, and cared for by younger surgeons. Preoperative MRI was associated with a higher likelihood of additional imaging and biopsies, greater than 30 day wait time to surgery, and higher rates of mastectomy as well as contralateral prophylactic mastectomy.
These findings were discussed by Drs. Habib Rahbar and Constance Lehman in an accompanying editorial. They pointed out several limitations in the study, such as not knowing the MRI results, and not having the genetic mutations status (such as BRCA 1/2) of the patients. However, they noted that “this study adds to the growing body of evidence that the use of MRI in the preoperative setting is associated with more aggressive surgery of the affected breast”. They also noted that given concerns of breast cancer overtreatment, we need to modify our approach. They pointed out that MRI might be useful in developing individualized treatment approaches, such as multiple lumpectomies if more than one cancer is found (instead of mastectomy). They appropriately called for more research to determine how preoperative breast MRI should best be utilized.