A review board says a decision to caution, but not reprimand or discipline, a Windsor doctor who performed unnecessary breast surgeries was unreasonable.

The board has ordered a committee of the College of Physicians and Surgeons of Ontario to reconsider its decision on Dr. Barbara Heartwell.

Laurie Johnston complained to the college that Heartwell performed an unnecessary mastectomy on her in 2009 after the doctor admitted she misread the results of a biopsy that found Johnston didn't have cancer.

The college committee found Heartwell made a "significant error" and ordered her to be formally cautioned by the college.

Johnston appealed the finding to the Health Professions Appeal and Review Board, which said in a decision this month that there is no indication the discipline committee considered previous complaints against Heartwell.

The board said the committee should have addressed the case of another woman whose healthy breast was removed by Heartwell years earlier, whether or not it was the subject of a complaint to the college.