The number of mastectomies performed for early-stage breast cancer at the Mayo Clinic increased by 13% over a three-year period. Increasing use of preoperative magnetic resonance imaging (MRI) may explain some of the increased use of mastectomy. These results were presented at the 2008 annual meeting of the American Society of Clinical Oncology.
Early-stage breast cancer is often treated with breast-conserving therapy (lumpectomy plus radiation therapy). In 1990, the National Institutes of Health issued a statement that breast-conserving therapy is as effective as mastectomy (total breast removal), with respect to overall survival, for most women with Stage I or Stage II breast cancer. Since that time, rates of mastectomy have fallen among women with early-stage breast cancer as more women have chosen breast-conserving therapy.
A factor that may contribute to a reversal in this trend is preoperative breast MRI.
Breast MRI can detect both cancerous and noncancerous changes to the breast. Detection of additional breast abnormalities may prompt women and their physicians to consider mastectomy in place of breast-conserving therapy, even though both types of treatment result in similar survival.
To explore trends in use of mastectomy among women with early-stage breast cancer, researchers at the Mayo Clinic evaluated information from 5,464 women who had surgery for early-stage breast cancer between 1997 and 2006.
- Mastectomy rates declined from 45% in 1997 to 30% in 2003, but then increased to 43% in 2006.
- Rates of preoperative MRI increased from 11% in 2003 to 22% in 2006.
- 52% of women who had preoperative MRI chose a mastectomy, compared with 38% of women who did not have preoperative MRI.
- Although mastectomy rates were lower in women who did not have an MRI, mastectomy rates also increased in these women between 2003 and 2006.
This study suggests that preoperative breast MRI may contribute to an increased use of mastectomy among women with early-stage breast cancer. Other factors may also be contributing to use of mastectomy, however, such as improvements in breast reconstruction and increasing use of genetic testing.
Reference: Katipamula R, Hoskin TL, Boughey JC et al. Trends in mastectomy rates at the Mayo Clinic Rochester: Effect of surgical year and pre-operative MRI. Proceedings from the 44th annual meeting of the American Society of Clinical Oncology. Chicago, IL. 2008. Abstract #509.