Patients with multiple tumors in one breast may not need mastectomy, research finds

Patients who have multiple tumors in one breast may be able to avoid a mastectomy if the tumors can be removed while leaving enough breast tissue, according to research led by the Alliance in Clinical Trials in Oncology and Mayo Clinic Comprehensive Cancer Center. Patients would receive breast-conserving therapy: a lumpectomy followed by whole-breast radiation therapy, rather than mastectomy. The study is published in the Journal of Clinical Oncology.

"I am excited about these findings because it will empower patients and the multidisciplinary care teams caring for patients to be thinking about this option for women who may want to preserve their breast," says Judy Boughey, M.D., lead author and breast surgical oncologist, and the W.H. Odell Professor of Individualized Medicine. "Some patients may still prefer or require a mastectomy, and that is a perfectly fine approach. But being able to provide more patients diagnosed with breast cancer with a choice is a great step forward."

The prospective, single-arm trial, a study where all women enrolled in the trial are treated the same way, looked at data from 204 eligible women over 40 that had two or three separate areas of breast cancer in the same breast and were interested in breast conservation. All patients had a preoperative mammogram and/or ultrasound, and all but 15 had a breast MRI. They had lumpectomies to remove tumors, followed by whole-breast radiation with radiation boost to each lumpectomy site. The women were observed for five years for subsequent breast cancer events.

The data after five years showed that at a median follow-up of 66.4 months, six patients had a local recurrence. The rate of cancer local recurrence was 3.1%. This is an excellent outcome and is similar to the local recurrence rate for patients with a single tumor in a breast who had breast-conserving therapy, Dr. Boughey says.

Historically, women with multiple tumors in one breast have been advised to have a mastectomy. Now, patients can be offered a less invasive option with faster recovery, resulting in better patient satisfaction and cosmetic outcomes, Dr. Boughey says.

An additional finding is that the local recurrence rate was lower in patients who had a preoperative MRI than in those who did not have an MRI before surgery. For patients who have two or three tumors in a breast and are considering breast conservation, an MRI before surgery should be considered to ensure there is not more extensive disease, Dr. Boughey says. Several other factors, such as breast size, will influence whether a patient would be able to be offered breast-conserving therapy, she adds.