Breast MRI may help personalize treatment for DCIS patients

Pairing breast MRI with a test that characterizes breast cancer genes can lead to a more personalized treatment approach for patients with ductal carcinoma in situ (DCIS), reported authors of a recent study published in JAMA Oncology.

The study, which included 75 institutions, enrolled 339 women with DCIS on core biopsy who were also eligible for wide local excision (WLE) surgery. Patients received breast MRI before surgery and those results were considered when determining surgical choice. A test called the 12-gene DCIS score assay—a 10-year risk recurrence test on a scale of 0 to 100—guided radiotherapy recommendations.

Results showed 65 of those eligible for WLE prior to MRI converted to mastectomy. Of that total, 25 cases based their choice on the MRI findings, followed by patient preference in 25 cases, positive margins after attempted WLE in 10, positive genetic test results in 3 and contraindication to radiotherapy in 2 cases.

Additionally, of the 171 women eligible for radiotherapy because of their DCIS score, 89 women (52 percent) had intermediate or high scores. From that total, 93 percent underwent radiotherapy.

“Our study is the first, to our knowledge, to prospectively quantify the association of patient preferences with surgeons’ opinions on the decision for surgery,” wrote Constance D. Lehman, MD, PhD, with Massachusetts General Hospital in Boston, and colleagues. “Our findings that more than half of decisions to undergo mastectomy were attributable to factors other than MRI findings highlight the complexity in the shared decision-making process between patients and physicians in this context.”

Lehman et al. cited numerous strengths and weaknesses of their study. Among its strengths was its inclusion of multiple sites and its evaluation of patient and surgeon values when determining reasons for selecting procedures. One of its weaknesses, according to the group, was slightly more than 80 percent of patients enrolled cited WLE as their preferred treatment, potentially meaning those patients were more motivated to choose the procedure.

“This trial may provide useful preliminary information required for designing a planned randomized clinical trial to determine the effect of MRI and DCIS score on surgical management, radiotherapy, overall resource utilization, and clinical outcomes, with the ultimate goal of achieving greater therapeutic precision,” the authors concluded.