University of California San Francisco
Helen Diller Family Comprehensive Cancer Center

DCIS Is Not Invasive Breast Cancer, and Might Not Require Surgery

By Jeffrey Norris, UCSF Science Cafe | March 30, 2009

Tens of thousands of women are having surgery -- sometimes even having both breasts removed -- to treat a condition that is unlikely to ever become life-threatening.

In fact, a recent study concluded that a small, but growing minority of women with the condition -- called ductal carcinoma in situ, or DCIS -- are choosing to undergo a double mastectomy. That's despite a lack of evidence for any survival benefit over less invasive surgery. But the fear is little surprise, given what's unknown about DCIS.

UCSF breast cancer oncologist Shelley Hwang, MD, is bucking this trend toward more invasive treatment. Her clinical research team is investigating whether at least some women with DCIS can safely omit surgery altogether from their treatment. In the course of their studies, the researchers also hope to fill in some of the knowledge gaps surrounding the condition.

DCIS looks like cancer. It generally grows as a small collection of cells lining the breast's milk ducts. But DCIS cells do not behave in the same way as the cells of an invasive breast tumor - pathologists can tell them apart. Unlike invasive breast cancer cells, DCIS cells do not have the capability to spread and grow in distant parts of the body. And unlike invasive breast cancer, DCIS is not life-threatening.

Unfortunately, women who are diagnosed with DCIS have a higher than average risk of developing invasive breast cancer later -- although some never will. As it stands, there is no proven way to predict which women diagnosed with DCIS will eventually develop invasive breast cancer. But because of the elevated risk, surgery to remove DCIS -- generally a lumpectomy with radiation, or mastectomy -- has become standard treatment. Treatment options are the same as for early-stage invasive breast cancer.

Hwang is exploring to what extent targeted drug treatment with careful follow-up might become a low-risk alternative to surgery for many of these women.

The question is hugely important -- DCIS is epidemic. Blame mammography. To detect breast cancer at earlier, more treatable stages, mammography guidelines now call for screening women as young as age 40, and compliance with screening guidelines has increased. When there was less screening, many fewer cases of DCIS were diagnosed.

Hwang has launched clinical trials to explore drug treatment for DCIS. At an annual retreat for members of the UCSF Helen Diller Family Comprehensive Cancer Center's Breast Oncology Program, Hwang described some preliminary findings from a study of 62 women diagnosed with DCIS who underwent three months of drug treatment - prior to surgery in most cases.

Read more at Jeffrey Norris, UCSF Science Cafe