Following a steady decline over seven years, mastectomy rates for early-stage breast cancer have increased in recent years, according to new data from the Mayo Clinic in Rochester, Minnesota. The increase in mastectomy versus lumpectomy may be partially related to the introduction of pre-operative breast magnetic resonance imaging (MRI), according to researchers.
Dr. Matthew P. Goetz of the Mayo Clinic discussed the research Thursday at a press conference hosted by the American Society of Clinical Oncology. The study will be presented in Chicago at ASCO's annual meeting, which begins May 30.
Dr. Goetz and colleagues analyzed trends in rates of mastectomy compared with breast conserving therapy and their relationship to preoperative breast MRI and surgical year among a cohort of more than 5,400 women who had surgery for early-stage breast cancer at Mayo Clinic between 1997 and 2006.
They found that mastectomy rates declined significantly from 45 per cent in 1997 to 30 per cent in 2003. However, "during the period 2004 to 2006, there was a significant increase in mastectomy rates, and in 2006 the mastectomy rate was 43 per cent, similar to the rate initially seen in the late 1990s," Dr. Goetz reported.
The percentage of women who had preoperative breast MRI doubled from 11 per cent in 2003 to 22 per cent in 2006.
For women who had preoperative MRI, the mastectomy rate was significantly higher over the 4-year period from 2003 through 2006. "Overall, women who had preoperative breast MRI had a mastectomy rate of 52 versus 41 per cent for women who did not have preoperative MRI," Dr. Goetz reported.
He said it's important to note, however, that the mastectomy rate also increased in women who did not undergo preoperative breast MRI. In 2003, the mastectomy rate for women who did not have MRI was 28 per cent and in 2006 it had increased to 41 per cent.
Therefore, Dr. Goetz concluded, while MRI may be one factor, there likely are "additional reasons for the increase in the mastectomy rate that we were unable to account for in this study. We do know that there have been changes over the last several years including new reconstruction options, patient preferences, and the introduction of genetic testing."
"Future studies will be needed to determine those factors most likely to influence the change in surgical management and whether those changes influence breast cancer outcomes or quality of life," he concluded.
