Aging shown to drive up overall DCIS detection rates

A retrospective study of nearly three quarters of a million women in Germany shows that, as women age, their chances rise for having ductal carcinoma in situ (DCIS) detected in screening.

According to the researchers behind the study, the overall tendency owes to an increase in DCIS de­tection rates for high- and intermedi­ate-grade DCIS, the “precursor lesions” that may or may not progress to more aggressive types of breast cancers.

Stefanie Weigel, MD, of University Hospital Muenster, and colleagues published the findings online in the RSNA journal Radiology.

The study divided 733,905 women aged 50 to 69 years into five-year age groups. The sample included 989 graded DCIS diagnoses (detection rate, 1.35 percent).

Of these, 419 were of high-grade DCIS (detection rate, 0.57 percent), 388 were of intermediate-grade DCIS (detection rate, 0.53 percent) and 182 were of low-grade DCIS (detection rate, 0.25 percent).

Detection rate for all types of DCIS, taken together, increased significantly with age: 

• 50–54 years, detection rate of 1.15 percent (254 of 220,985 women);
• 55–59 years, detection rate of 1.23 percent (218 of 177 782 women);
• 60–64 years, detection rate of 1.34 percent (201 of 150 415 women); and
• 65–69 years, detection rate of 1.71 percent (316 of 184 723 women).

Meanwhile the detection rate for high-grade DCIS showed a significant increase with age (odds ratio, 1.18 per 5-year age group), while the increase was lower for intermediate-grade DCIS (odds ratio, 1.11) and not significant for low-grade DCIS.

The women were first-time screening patients. They were screened between October 2005 and December 2008 during the implementation phase of a Germany-wide screening program coordinated through the Epidemiologic Cancer Registry of North Rhine–Westphalia.

Weigel told RSNA that the possibility of DCIS-related overdiagnosis must be balanced against the “robust evidence that high-grade DCIS is more likely to recur and to progress” to invasive carcinoma.

“Adequate therapy of non-symptomatic high-grade DCIS detected at screening needs further evaluation, as there is the chance to prevent aggressive invasive breast cancer, which could be life-threatening even in older age groups,” Weigel says. “In terms of overdiagnosis and overtreatment, there is need for more detailed prognostic characterization of DCIS lesions and weighting them in the context of age.”

A RSNA press release noted the results are likely to provide fodder for further debate over the pros and cons of screening older women for breast cancer.

Weigel and colleagues conclude, “The discussion about upper age limits and minimal intervals in mammography screening should be focused on effectiveness of detection of invasive cancers.”