Dr Khan on Optimizing Local Therapy Using MRI and a 12-Gene Expression Assay in DCIS

Seema A. Khan, MD, Bluhm Family Professor of Cancer Research, professor, surgery (breast surgery), Northwestern University Feinberg School of Medicine, discusses 5-year clinical outcomes from the ECOG-ACRIN E4112 trial (NCT02352883), which is evaluating the use of MRI and a 12-gene expression assay to optimize local therapy for patients with ductal carcinoma in situ.

ECOG-ACRIN E4112 is evaluating 5- and 10-year ipsilateral breast event rates in patients with DCIS who received wide local excision after MRI-guided surgery. At a median follow-up of 5 years, the rate of ipsilateral breast events in patients with a low DCIS scoredefined as under 39 (n = 82) who received a radiotherapy recommendation based on their score was 5.1% (95% CI, 1.9%-12.9%). This rate was 4.5% (95% CI, 1.7%-11.7%) in patients with an intermediate or high DCIS score defined as 39 or higher who received a radiotherapy recommendation based on their score. In patients who adhered to their DCIS score–based radiotherapy recommendation (n = 159), the rate of ipsilateral breast events in those with a low DCIS score who did not receive radiotherapy was 5.5% (95% CI, 2.1%-14.1%). This rate was 4.8% (95% CI, 1.8%-12.3%) in patients with an intermediate or high DCIS score who received radiotherapy.

The findings from this study confirm that the risk of ipsilateral breast cancer recurrence is low in patients with DCIS who are predicted to have low-risk disease per DCIS score, Khan says. Moreover, data also suggest that in those who are predicted to have high-risk disease, radiation can reduce the risk of recurrence to rates that are comparable to those observed in patients with low-risk disease, Khan says. Therefore, molecular assay results can inform radiation decisions in patients with DCIS, Khan emphasizes. Prior to this study, little prospective data existed to determine the role of DCIS scores in radiotherapy decision making, Khan explains. The prospective data from ECOG-ACRIN E4112 validate hypotheses generated from prior retrospective studies, Khan concludes.

Disclosures: Dr Khan has no financial relationships to disclose.