Date of publication: October 30, 2013
In a study of women with breast ductal carcinoma in situ (DCIS), the long-term risk of a cancer recurrence or a new breast cancer appeared to be highest among women with triple-negative DCIS. These results were published in BMC Cancer.
DCIS refers to abnormal cells in the lining of a breast duct. It is classified as Stage 0 breast cancer-the earliest possible stage. The condition usually does not produce any symptoms (such as a breast lump), and is most commonly detected by screening mammography. Treatment outcomes are generally quite good, but some women do experience a recurrence or a second, new breast cancer.
To explore whether outcomes with DCIS vary by subtype of DCIS, researchers in Scandinavia conducted a study among 458 women with DCIS. DCIS was categorized on the basic of hormone receptor status, HER2 status, and Ki67. This type of subtyping was developed for use in invasive breast cancer (not DCIS), but in this study the researchers tested DCIS for these characteristics.
Of the 458 cases, 381 were successfully subtyped. The most common subtype was Luminal A, which accounted for close to half of all cases. Luminal A cancers are hormone receptor-positive, HER2-negative, and low Ki67. Roughly 7% of cases were triple-negative.
Outcomes of interest included recurrence (in or near the affected breast or at more distant locations in the body) and development of a new cancer in the opposite breast. During the first 10 years after DCIS diagnosis, the frequency of these outcomes was generally similar regardless of DCIS subtype. After 10 years, women with triple-negative DCIS were more likely than women with other subtypes of DCIS to develop a new or recurrent cancer.
These results should be interpreted cautiously: only 27 of the women had triple-negative DCIS. Larger studies would provide more reliable information about whether and how recurrence risk varies by DCIS subtype. Other characteristics of the DCIS may also prove to be important predictors of DCIS outcome.