By Kathleen Doheny
TUESDAY, Oct. 27, 2015 (HealthDay News) -- While experts know the chances of finding a type of early stage breast cancer known as DCIS increase with age, a new study from Germany shows these cancers are more likely to be aggressive when discovered in older women.
"DCIS detection rates increase with age, mostly due to a rise of DCIS high- and intermediate-grade [tumors]," said Dr. Stefanie Weigel, a researcher at University Hospital Muenster in Germany. These tumors, she said, are lesions that "carry a higher risk for transition to aggressive cancers than DCIS low-grade."
DCIS, or ductal carcinoma in situ, is an early stage cancer that is potentially invasive. It is confined within the milk ducts and a common finding on mammography. Treating DCIS is controversial, because some cases may never progress and cause problems during a woman's lifetime.
Weigel's team aimed to look at the link between age at screening and detection rates of the different grades of DCIS. The investigators looked at the medical records of nearly 734,000 women, aged 50 to 69, who were screened with digital mammography between 2005 and 2008.
The study authors looked at DCIS rates for five-year age groups, determining the rate per 1,000 women. They then divided their findings into DCIS of low-, intermediate- and high-grades.
In all, the investigators found 989 DCIS diagnoses. Of those, 419 were high-grade, 388 were intermediate-grade and 182 were low-grade, according to the report published online Oct. 27 in the journal Radiology.
The older the woman, the more likely she was to have a DCIS found, mostly due to an increase in intermediate- or high-grade DCIS. In the group aged 50 to 54, just 1.2 percent had a DCIS finding. By ages 65 to 69, 1.7 percent did, the findings showed.
What is new about this study is the finding about the grades, Weigel said. That is important because the higher the grade, the more likely the progression to invasive cancer, she explained. "For the most aggressive type, high-grade DCIS, intervals between DCIS detection and the occurrence of invasive carcinoma have been described to be five years, on average," Weigel added.
The findings confirm other research that has shown DCIS increases with age, said Dr. Rita Gidwaney, an assistant clinical professor of diagnostic radiology at the City of Hope Cancer Center, in Duarte, Calif.
Even though the rate of DCIS increased as women got older, Gidwaney said, the sensitivity of mammography to pick up DCIS does not vary with different ages. About 85 percent of DCIS cases were found on screening mammograms, she said.
Gidwaney does take issue with the study design, which omitted women aged 40 to 49. These younger women tend to have more aggressive cancers, so including them in the study would have been ideal, Gidwaney said.