MRI Does Not Improve Staging Compared with Conventional Methods in Early Breast Cancer

The use of magnetic resonance imaging (MRI) prior to breast-conserving surgery does not improve loco-regional staging compared with conventional staging methods among women with early breast cancer. These results were presented at a plenary session at the 2008 San Antonio Breast Cancer Symposium.

Staging for early breast cancer prior to surgery typically involves mammogram, ultrasound, and biopsy. Retrospective data has indicated that MRI used in this staging process may provide more accurate staging information, which may reduce unnecessary mastectomy or re-operation. However, no prospective randomized trials evaluating this issue have been performed until the COMICE trial.

The COMICE trial is the first prospective randomized trial evaluating MRI in women with breast cancer as a loco-regional staging method prior to surgery. The trial included 1,623 women who underwent triple staging assessment including mammogram, ultrasound, and biopsy prior to scheduled wide excision. Patients were then randomized to MRI imaging.

• The positive predictive value of MRI imaging was 61.8%, and the negative predictive value was 83.7%.
• There were no differences in survival or quality of life between the two groups of patients; however, one-third of the patients in the group that did not receive MRI expressed anxiety that they had not undergone the additional screening.
• MRI did not predict reoperation rates, which were 18.75% for those who underwent MRI compared with 19.33% for those who did not undergo MRI (OR=0.96, p=0.7691).
• MRI accurately detected additional cancerous lesions in nearly 5% of patients who underwent MRI; however, this did not reach statistical significance.
• Young age and lobular cancer were the only significant predictors of reoperation rates.

The researchers concluded that the additional MRI for loco-regional staging prior to breast-conserving therapy does not appear to warrant the extra cost as no significant differences in survival or reoperation rates were achieved compared with standard staging methods.

Reference: Drew P, et al. The UK NIHR multicentre randomised COMICE trial of MRI planning for breast conserving treatment for breast cancer. Proceedings from the 2008 San Antonio Breast Cancer Symposium. Abstract 51.