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Ductal carcinoma in situ (DCIS) differs from breast cancer because it is noninvasive, so it cannot spread to other parts of the body. However, it can progress to an invasive breast cancer, which can be life-threatening. Researchers from the Netherlands Cancer Institute wanted to determine how DCIS affected long-term survival.
The team studied almost 10,000 postmenopausal 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 rates of the general population. They found that women who had been treated for DCIS had a 2.5% risk of dying of breast cancer over 10 years and a 4% risk at 15 years — rates that were higher than in the general population. But they also found that DCIS survivors had a 10% lower risk of dying from any cause compared with the general population. They presented their results Jan. 27, 2017, at the European Cancer Congress.
DCIS is usually detected through screening mammography. The researchers speculated that the overall death rate for DCIS survivors may be lower than expected because women who undergo regular screenings may be healthier than those who don't. This study should provide reassurance that a diagnosis of DCIS does not raise the overall risk of dying. However, additional studies are necessary to determine why.