A major study this week in JAMA Oncology, which looked at mortality rates following a diagnosis of ductal carcinoma in situ (DCIS), provided some important insights and challenged preconceived notions.
It also spurred even more questions.
There’s a lot to unpack in the study, authored by Steven A. Narod, MD, of the University of Toronto and Women’s College Hospital in Toronto, and colleagues. Among the headline findings:
While physicians have long wondered how to approach DCIS—is it a lethal cancer in itself or merely a precursor to one?—researchers found some cases of DCIS have “an inherent potential for distant metastatic spread.”
Breast cancer-specific mortality for those with DCIS was 3.3 percent at 20 years of follow-up, which is 1.8 times greater than the rate for the general U.S. population.
For those diagnosed with DCIS, the risk of dying from breast cancer was elevated for women who later experienced an ipsilateral invasive cancer, those who were diagnosed before age 35 and black women.
While radiotherapy and mastectomy are used to successfully reduce the rate of ipsilateral invasive recurrence, these techniques did not improve breast cancer-specific mortality.