Presenter denies breast MRI causes more mastectomies

The higher rate of mastectomy among breast cancer patients imaged with MRI may be due to selection bias as opposed to the modality itself, according to a study presented at the RSNA scientific assembly Nov. 28.

There has been much debate within the scientific community about whether breast MRI increases the rate of mastectomy. Some researchers say MRI leads to more mastectomies while others argue other factors influence the suggestion.

“From our retrospective data we cannot determine the impact of MRI as a single factor regarding surgical planning, and neither can we define a causal association between breast MRI and mastectomy,” said Dr. Fabio Chiesa, from the University of Genova in Genoa, Italy, and presenter of the study.

The researchers reviewed five years of information in the electronic database of their institution to determine whether the use of breast MRI for preoperative staging of breast cancer was associated with an increased mastectomy rate. They found preoperative staging MRI was performed in 105 patients. The mastectomy rate for the total number of performed surgical treatments fluctuated by year from 13% to 21.4% with no discernible pattern emerging.

The overall rate of mastectomies for the period from 2003 to 2008 was 17.1%. The stratified mastectomy rate was 37.1% for the patients who underwent preoperative MRI and 14.6% for the patients staged without MRI.

The higher mastectomy rate in patients who performed preoperative MRI can be easily explained by the preferred use of preoperative MRI in patients with a higher suspicion of extensive disease at clinical examination and conventional imaging such as mammography and sonography, Chiesa said.

“In conclusion, according to our experience, breast MRI can be implemented in clinical practice for preoperative treatment planning without significantly increasing the overall mastectomy rate,” he said.