Women over 50 treated for ductal carcinoma in situ (DCIS) are as likely to be alive 10 years after diagnosis as people who never had this disease, and might even be healthier than the general population, data presented at the recent European Cancer Congress 2017 show.
“Ductal carcinoma in situ can be a worrying and confusing diagnosis for many women, especially due to the word ‘carcinoma,’ Philip Poortmans, president-elect of ECCO and head of the Radiation Oncology Department at Radboud University Medical Center, said in a press release. DCIS is non-invasive cancerous lesion of the milk ducts, and does not spread. But, as Poortmans also noted, it can progress into a breast cancer that is invasive.
Improved screening programs and their use is leading to increasing numbers of women being diagnosed with DCIS, but these findings are reassuring. Essentially, they say that although these patients’ risk of dying from breast cancer is higher than in women in general, they have a lower risk of dying from any cause.
The team led by Dr. Jelle Wesseling, a breast pathologist at the Netherlands Cancer Institute, studied nearly 10,000 Dutch women who were diagnosed with DCIS between 1989 and 2004.
After following the women for an average of 10 years, the researchers found that women diagnosed with DCIS had a 2.5% and 4% risk of dying from breast cancer at 10 and 15 years, respectively, which was slightly higher than that of women not diagnosed with the disease. These death rates, however, were falling over time.
And women 50 or older with DCIS were 10% less likely to die of any cause than women in the general population.
“It might seem surprising that this group of women actually has a lower mortality rate than the general population,” said Dr. Lotte Elshof, a research physician and epidemiologist at the Cancer Institute who analyzed the data and presented it at the congress, held Jan. 27-30 in Amsterdam. “However, the vast majority would have been diagnosed via breast screening, which suggests they may be health-conscious and well enough to participate in screening.”
The findings also reassure women who received radiotherapy to treat their DCIS, because its side effects can include damage to surrounding organs, like the heart or lungs. But these women also had a lower risk of dying from diseases of the circulatory, digestive, and respiratory systems, as well as from other cancers.
“Remarkably, the increased risk of dying from breast cancer is completely offset by a lower risk of dying from other causes compared to women in the general population,” Poortmans said. “This might be explained by the generally better health and socioeconomic status of women who regularly participate in breast cancer screening. This could also be tested in the on-going research.”
The team is now starting to work with U.K. and U.S. researchers to increase its sample size and understand why some women with DCIS progress into invasive cancer, while other do not.
“We are eagerly waiting for the results of further research to identify the factors — including age, as clearly shown in this study —that contribute to the risk for recurrence and progression from DCIS for each individual patient,” Poortmans said.