About three-quarters of women newly diagnosed with breast cancer have a friend or family member with them at their first visit with a surgeon. And that person plays a significant role in the patient's decision of what type of surgery to have, according to a new study from the University of Michigan Comprehensive Cancer Center.

The study looked at factors affecting a woman's choice between a mastectomy to remove the entire breast or breast-conserving surgery, which involves removing only the tumor and is followed by radiation treatments. It found that when the patient, rather than the doctor, drives the surgery decision, the patient is more likely to choose a mastectomy. This proved to be the case among all racial and ethnic groups.

The paper was published in the Journal of the National Cancer Institute.