New research helps clarify the long-term risk for invasive breast cancer in women with ductal carcinoma in situ (DCIS) who opt for breast-conserving surgery alone or with radiotherapy. 

The study suggests that surgery for DCIS followed by radiotherapy reduces the odds of cancer initially but this benefit diminishes over time, compared with surgery alone. 

The findings were presented during the 12th European Breast Cancer Conference (EBCC12) by Dr Maartje van Seijen of the Netherlands Cancer Institute in Amsterdam. 

The study included more than 10,000 women diagnosed with DCIS in the Netherlands from 1989 to 2004. Of these, 2647 underwent breast-conserving surgery alone while 2604 had breast-conserving surgery plus radiotherapy, and 4794 had a mastectomy.