Oral agents and “watchful waiting” might make it possible to delay or avoid overtreatment with surgery and radiotherapy for many women diagnosed with ductal carcinoma in situ (DCIS), according to Henry Kuerer, MD, PhD, FACS, CMQ, professor of surgery and director of the breast surgical oncology training program at the University of Texas MD Anderson Cancer Center in Houston, Texas.
Dr. Kuerer reviewed the rationale for this approach and several clinical trials that should help to build the evidence base, at the 33rd Annual Miami Breast Cancer Conference, held March 10–13 in Miami Beach, Florida.
Mammographic screening has been tied to a greater than 500% increase in DCIS diagnoses, but Dr. Kuerer noted that 50% to 70% of women with DCIS do not go on to develop invasive breast cancers.
“DCIS itself is not harmful,” he said. DCIS treatment is therefore aimed at preventing development of life-threatening breast cancers. But current imaging, clinical, pathological, and molecular tests are “insufficient” to reliably rule out invasive cancer or to spot early progression of invasive disease, he explained. That leads to overtreatment of DCIS, he believes.
“DCIS is an ideal opportunity to study promising agents with pre-op window studies,” Dr. Kuerer said. Patients should be identified for observation studies to evaluate active surveillance, he argued.
Clinical trials like EORTC LORD and the UK-based LORIS are under way to assess active surveillance for patients with low- and intermediate-grade DCIS. The COMET (Comparison of Operative vs Medical Endocrine Therapy for Low-Risk DCIS) trial will similarly compare standard of care and active surveillance for low-risk DCIS patients in the United States.
“We need as a community to support these studies so we can make advances in the field,” Dr. Kuerer urged.
“LORIS recruitment is on target” and an additional 40 sites will join the study in July 2016, Dr. Kuerer reported. The LORD trial, an international multicenter study, will begin enrolling women with biopsy-confirmed unilateral, pure grade I DCIS later this year, he said.
Dr. Kuerer said that he is unsure that patients in the United States “really want” surveillance as an option in “an era of more mastectomy and contralateral mastectomy.”