ECCO 2017: Low Cause-Specific Mortality in Women Over 50 Treated for Ductal Carcinoma in Situ
Women over 50 who have been treated for ductal carcinoma in situ (DCIS) are more likely to be alive 10 years later than women in the general population, according to new research presented by Elshof et al at the 2017 European Cancer Congress (ECCO) (Abstract 173).
DCIS differs from breast cancer because it is noninvasive. However, because it can progress into an invasive breast cancer, it is usually treated with surgery or surgery and radiation therapy. The number of women being diagnosed with DCIS is increasing due to advances in breast cancer screening techniques.
The findings, presented at the Congress by Lotte Elshof, MD, research physician and epidemiologist at the Netherlands Cancer Institute, show that although women with DCIS have a higher risk of dying from breast cancer, overall, they have a slightly lower risk of dying from any cause. Netherlands Cancer Institute researchers explained their results should provide reassurance to women who are diagnosed with the disease.
Study Findings
Led by Jelle Wesseling, MD, PhD, a breast pathologist at the Netherlands Cancer Institute, the team studied data on almost 10,000 Dutch women who were diagnosed with DCIS between 1989 and 2004. They tracked the patients over an average of 10 years and compared their death rates with the expected mortality in the general population.
They found that women over 50 who had been treated for DCIS had a 10% lower risk of dying from any cause compared to the general population.
Dr. Elshof, who analyzed the data, told the Congress, “Being diagnosed with DCIS can be extremely distressing, and research indicates that many women overestimate the risks involved and are confused about treatment. This study should provide reassurance that a diagnosis of DCIS does not raise the risk of dying.”
“It might seem surprising that this group of women actually has a lower mortality rate than the general population,” she continued. “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 study shows that patients with DCIS had a 2.5% risk of dying of breast cancer after 10 years. At 15 years, the risk was 4%. These rates are higher than in the general population. However, the study also showed that the rates were getting lower in women diagnosed with DCIS more recently.
Patients with DCIS were 10% less likely to die from all causes combined compared to the general population. Specifically, they had a lower risk of dying from diseases of the circulatory, respiratory, and digestive systems, as well as other cancers. The researchers say this finding is important, because treating DCIS with radiotherapy could cause side effects, including damage to nearby organs such as the heart.
The team are beginning an international collaboration with researchers in the United Kingdom and United States.
This will allow them to increase the size of the study and to try to understand why some cases of DCIS progress into invasive cancer while others do not.
Commentary
Philip Poortmans, MD, PhD, President-Elect of ECCO and Head of the Radiation Oncology Department at Radboud University Medical Center in Nijmegen, The Netherlands, said about the findings, “Ductal carcinoma in situ can be a worrying and confusing diagnosis for many women, especially due to the word ‘carcinoma’. Although it should be considered as being clearly different from breast cancer, it can progress into breast cancer, even after removal of the entire breast or after breast-conserving therapy consisting of surgery, generally combined with radiation therapy.”
“Moreover, those treatments can have side effects, including on the heart. This research provides reassurance for women diagnosed with DCIS because it shows that they are as likely to be alive 10 years after the diagnosis as people in the general population who did not have DCIS. This is also reassuring with regards to the potential risks of side effects.”
“However, we have to recognize that in one-fifth of the patients who die, the cause is breast cancer, which is likely to result from progression of the DCIS they were diagnosed with. Therefore, 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.”
“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. 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 ongoing research.”
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
