DCIS Recurrence Rates Cut in Half

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 a new study to be presented at the 2015 American Society of Clinical Oncology (ASCO) Breast Cancer Symposium in San Francisco (abstract 32).

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

After breast-conserving surgery, DCIS patients show substantial rates of recurrence, with half of recurrences being invasive, according to the researchers. The decrease in local recurrence for invasive breast carcinoma has been largely attributed to improvements in systemic therapy.

Among the 2,996 cases, they found recurrences in 363 patients (12%). Median follow-up for patients without recurrence was 75 months; 732 patients were followed for 10 or more years.

DCIS patients who were treated in more recent years (1999–2010) had a 40% lower risk of cancer recurrence than those treated earlier (1978–1998); 5-year recurrence rates fell from 13.6% to 6.6% over those time periods.

The significant decline held up after the researchers controlled for factors known to affect recurrence, including increased screening, more frequent use of adjuvant therapies, and wider surgical margins.

After stratification by radiation use, and adjustment for seven other factors, the decrease in recurrence rates was limited to those without radiation. “There was no decline in recurrence rates among those receiving radiation,” according to Dr. Zee, in a press release.

In conclusion, the researchers note that “recurrence rates for DCIS have fallen over time. 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 it is not due to changes in radiation efficacy, but may be due to improvements in radiologic detection and pathologic assessment.”

They believe that it is important for clinicians to educate DCIS patients about the lower recurrence risk for those treated more recently, particularly in light of reports of increased use of mastectomy among DCIS patients.

ASCO Expert Harold J. Burstein, MD, PhD, associate professor of medicine at Harvard Medical School, commented: “Over the past 3 decades, substantial progress has been made in lowering the risk of breast cancer recurrence after treatment. This study demonstrates that multidisciplinary care, combined with advances in management and detection, is making a tangible difference for women with DCIS.”