Early Stage Breast Cancer May Not Impact Mortality Risk

Patient with ductal carcinoma in situ had a lower risk of all-cause mortality compared with the general population.

Women treated for ductal carcinoma in situ (DCIS) are likely to live as long as women who have not been diagnosed with cancer, according to a study presented at the European Cancer Congress 2017.

The researchers found that patients over age 50 who had a DCIS diagnosis were more likely to live 10 years longer, compared with women in the general population.

DCIS cannot metastasize, and is generally considered to be non-aggressive. However, it can turn into breast cancer if left untreated. Increased occurrence of DCIS is largely due to an uptake of breast cancer screenings, which is beneficial to patients since the tumor may turn cancerous in the future.

The investigators found that women with DCIS had an increased risk of dying from breast cancer, but had a lower overall risk of all-cause mortality, according to the study. The researchers believe that these findings should provide hope to women diagnosed with DCIS.

In the study, the investigators examined data of nearly 10,000 women diagnosed with DCIS between 1989 and 2004. Patients were followed up with for an average of 10 years.

When mortality rates for these patients were compared with those for the general population, the researchers discovered that women over 50-years-old who were diagnosed with DCIS had a lower risk of all-cause mortality compared with the general population, according to the study.

“Being diagnosed with DCIS can be extremely distressing, and research indicates that many women overestimate the risks involved and are confused about treatment,” said researcher Lotte Elshof, MD. “This study should provide reassurance that a diagnosis of DCIS does not raise the risk of dying.”

After 10 years, patients with DCIS had a 2.5% risk of breast cancer related mortality, which increased to 4% at 15 years, according to the study. While these rates are higher compared with the general population, the findings suggest that this rate is declining.

These patients had a lower risk of mortality related to circulatory, respiratory, and digestive system diseases, in addition to cancers.

“It might seem surprising that this group of women actually has a lower mortality rate than the general population,” Dr Elshof said. “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 researchers said that their findings are important because a majority of cancer treatments can lead to side effects, such as organ damage.

“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 ten years after the diagnosis as people in the general population who did not have DCIS,” Dr Elshof said. “This is also reassuring with regards to the potential risks of side-effects.”

Although these findings may provide hope to physicians and patients, additional research is needed to determine if health and socioeconomic status of women who undergo regular breast cancer screening may lead to lower mortality rates.

“However, we have to recognise [sic] 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,” Dr Elshof concluded. “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.”