By E.J. Mundell
MONDAY, Oct. 5, 2020 (HealthDay News) — Research following patients for nearly three decades finds that surgery plus radiation beats surgery alone for women with ductal carcinoma in situ (DCIS) — a common, early form of breast cancer that can become invasive cancer.
However, the study also found that any survival advantage for the combo treatment appears to fade over the long term.
Still, “overall, the addition of radiotherapy gives women the best chances,” concluded study leader Maartje van Seijen of the Netherlands Cancer Institute. She presented the findings Saturday at the European Breast Cancer Conference, held online this year.
One U.S. breast surgeon called the new study a “great opportunity” to glean new insights about DCIS.
“This article is unique, in that it follows a very large number of women with DCIS over a very long time — 10,045 women followed for 27 years,” said Dr. Alice Police, who wasn’t involved in the study. She’s regional director of breast surgery at the Northwell Health Cancer Institute in Sleepy Hollow, N.Y.
“DCIS is a common form of very early breast cancer where the bad cells have not spread out of the milk ducts,” Police explained. Because it is such an early form of breast cancers, there are concerns about “overtreatment,” she said.
The new research sought to address those concerns. In the study, Dutch women were diagnosed with a DCIS between 1989 and 2004. They were then treated with either breast-sparing surgery (lumpectomy) to remove the DCIS; breast-sparing surgery followed by radiotherapy, or a full mastectomy.
In the first 10 years after diagnosis, women who had breast-sparing surgery alone had a 13% risk of being diagnosed with DCIS again and a 13.9% risk of invasive breast cancer.
In contrast, women treated with breast-sparing surgery plus radiotherapy had a 4.6% risk of recurrent DCIS and a 5.2% risk of invasive breast cancer, the researchers reported.
But the differences between the two groups of women grew smaller with time. Ten or more years after their DCIS diagnosis, women who had breast-sparing surgery only had a 1.2% risk of recurrent DCIS and an 11.8% risk of invasive breast cancer.
Over the same interval of time, women treated with breast-sparing surgery and radiotherapy had a 2.8% risk of recurrent DCIS and a 13.2% risk of invasive breast cancer, van Seijen’s group said.
Women who had a mastectomy had the lowest risk of invasive breast cancer, the study found.
The findings clarify the long-term risks for women with DCIS and may help them and their doctors decide the best treatment for them, the study authors said.
“The risk of DCIS or invasive cancer recurring in these women will diminish over time, whether they had just the breast-sparing surgery or breast-sparing surgery with radiotherapy,” van Seijen said in a conference news release. Radiotherapy seems to provide a bit more protection, at least over the shorter term.
“There remains a chance of a new DCIS or invasive cancer developing that is