Five-year recurrence rates for women with ductal carcinoma in situ (DCIS) have been cut in half recently due to advances in mammography and more detailed pathology assessments according to research presented at the American Society of Clinical Oncology's Breast Cancer Symposium 2015.

The new retrospective analysis explores local recurrence rates for women with DCIS treated between 1978 and 2010.  Researchers, led by Kimberly J. Van Zee, MD, MS, FACS Memorial Sloan Kettering Cancer Center New York, NY, evaluated a prospectively maintained database of 2,996 women who underwent breast-conserving surgery (lumpectomy) at the center.

Patients with DCIS who were treated in recent years (1999-2010) had a 40% lower risk of cancer recurrence than those treated earlier (1978-1998).  Specifically, five-year recurrence rates fell from 13.6% to 6.6% over the course of these two periods (hazard ratio [HR] 0.62, p < 0.0001).

When researchers controlled for factors known to affect recurrence, such as increased screening, more frequent use of adjuvant therapies, and wider surgical margins, this significant decline was still evident.

The decrease in recurrence rates over the three decades was limited to women who did not receive radiation therapy.

The authors note that increases in screen-detection, negative margins, and use of adjuvant therapies only partially explain the decrease. The unexplained decline is limited to women not receiving radiation, suggesting that the decline in recurrence rates may be attributable to advances in the quality of mammography, as well as more detailed pathology assessments.

The lower recurrence risk observed for DCIS patients treated in more recent years is important for patient education, especially in view of the widely reported recent increase in use of mastectomy.

"Over the past three decades, substantial progress has been made in lowering the risk of breast cancer recurrence after treatment," said ASCO Expert Harold J. Burstein, MD, PhD, FASCO. "This study demonstrates that multidisciplinary care, combined with advances in management and detection, is making a tangible difference for women with DCIS."

Other authors were Preeti Subhedar, Cristina Olcese, Sujata Patil, Monica Morrow; Breast Service, Dept of Surgery, Memorial Sloan Kettering Cancer Center, New York, NY; Dept of Epidemiology and Biostatistics, Memorial Sloan Kettering Cancer Center, New York, NY.