Risk of invasive breast carcinoma among women diagnosed with ductal carcinoma in situ and lobular carcinoma in situ

Apr 10 2006

A new study of women with early stage, localized breast cancer identifies new patterns and risk factors for invasive disease that may influence how patients are treated.

Published in the May 15, 2006 issue of CANCER, a peer-reviewed journal of the American Cancer Society, the study reveals that patients with lobular carcinoma in situ (LCIS) are actually at higher risk of developing advanced stage tumors than previously thought. In addition, women with ductal carcinoma in situ (DCIS) who are under 50 years old, African-American or Hispanic are at increased risk of developing advanced stage invasive tumors.

In situ lesions, such as DCIS and LCIS, are early generation cancer cells that have not yet invaded adjacent tissue. The diagnosis of DCIS and LCIS has been increasing up to 7-fold since 1980, according to U.S. statistics. The increase is hypothesized to be due primarily to more screening mammograms and breast biopsies.

The significance of these confined lesions in the course of breast cancer continues to be explored. Current research indicates that DCIS and LCIS clinically have different courses and prognoses, and consequently, should have different treatments. Oncologists recommend surgery for DCIS, considered a precursor to same breast invasive cancer. In contrast, observation after biopsy is recommended for uncomplicated LCIS, which is thought to have little invasive risk but may be a risk factor for later breast cancer. A few small studies have suggested that LCIS has a risk for same and contralateral invasive tumors, prompting some to recommend bilateral mastectomy in high risk patients.

Researchers led by Christopher I. Li, M.D., Ph.D. of the Fred Hutchinson Cancer Research Center in Seattle reviewed data from 37,692 DCIS and 4,490 LCIS patients from 1988 to 2002 to identify demographic and tumor characteristics that are risk factors for invasive disease and the pattern of invasive disease that DCIS and LCIS develop.

One notable finding is that LCIS patients were at greater risk than DCIS patients for invasive lobular carcinoma (ILC), suggesting LCIS to be a precursor lesion to ILC, rather than simply a risk factor. Specifically, LCIS patients were five times more likely to develop ILC and slightly less likely to develop invasive ductal carcinoma (IDC) compared to DCIS patients. The authors also found that LCIS patients had higher rates of ipsilateral invasive breast cancer, but similar rates of contralateral invasive breast cancer, compared to DCIS patients suggesting that "localized treatment for LCIS may be warranted."

Among DCIS patients, women under 50 years old as well as Hispanic and African-American women were at greater risk for advanced stage invasive breast cancer, which is a more lethal form of the disease, than older and Caucasian women. Possible risk reduction strategies, conclude the authors, include increasing the recommended frequency of "screening women diagnosed with DCIS at a young age" and "improving the follow-up and screening of black women and Hispanic white women with DCIS."

This study has potential impact not only on in situ treatments but also risk stratification and follow-up recommendations for women with early stage breast cancer.