A 30-year-long population-based study, reported at the 14th European Breast Cancer conference held in Milan, Italy, showed that breast-conserving therapy for ductal carcinoma in situ (DCIS) had become increasingly effective in preventing the emergence of breast cancer over the long term, but that there were still unanswered questions.

The population-based Netherlands Cancer Registry retrospective cohort study of 25,719 women with DCIS diagnosed from 1989 up to 2021 (all of whom were treated with standard conservative therapy) found there were successes and limitations with the current standard of care for DCIS.

Surprisingly, long-term risk appeared to have been unrelated to tumor grade. Also, despite a continuing improvement in outcomes during this period, the investigators concluded that specific molecular predictors of outcome still needed to be identified to distinguish intrinsically low-risk tumors (that did not require even conservative therapy) from those that carry higher risk and are highly likely to benefit from breast-conserving surgery and radiotherapy.

After reporting the study findings in Milan, study author Adri Voogd, PhD, Associate Professor of Clinical Epidemiology in the Faculty of Health, Medicine, and Life Sciences at Maastricht University, Maastricht, The Netherlands, discussed their clinical implications with Peter Goodwin.