More than 14% of diagnosed breast cancers in the US are ductal carcinoma in situ (DCIS), a precancerous condition in which abnormal cells are found in the lining of the breast duct. The diagnosis of DCIS has increased significantly over the past couple of decades, due primarily to an increase in screening mammography , which can detect breast cancer in this early stage.

Research on the treatment of DCIS is limited, and has shown little consensus regarding the appropriate management of patients with this condition. Now that DCIS diagnosis is becoming increasingly common, have certain treatment patterns emerged?

A new study in the March 17, 2004 issue of the Journal of the National Cancer Institute set out to examine the current trends in managing DCIS. The researchers found that treatment of DCIS changed significantly between 1992 and 1999, and varied widely in the US, ranging from overly aggressive treatment to possible undertreatment.

About the Study

The study included 25,206 women aged 18 and older, diagnosed with DCIS between 1992 and 1999. The researchers obtained this information from a population-based cancer registry that included data from 11 distinct geographic areas.

The researchers looked at the rates of mastectomy (removal of the entire affected breast), axillary dissection (examination and removal of the lymph nodes in the arm pits), breast reconstruction, and radiation therapy following lumpectomy (surgical removal of the tumor only, sparing the breast). They then calculated the proportion of each type of treatment compared to the total number of DCIS cases.

The Findings

There was a dramatic 73% increase in the number of DCIS cases between 1992 and 1999. However, the incidence of the most serious form of DCIS, which often requires more aggressive treatment, did not change over the study period. Overall, 97.5% of the women had some form of surgery.

The rate of mastectomy decreased from 43% to 28% during the study period. Likewise, the rate of axillary dissection fell from 34% to 15%. However, the rate of axillary dissection remained high (30% in 1999) among women who had a mastectomy, even though this procedure is not routinely recommended for a mastectomy. Additionally, almost half of the women who had a lumpectomy did not undergo radiation therapy, despite the fact that many of these women could have potentially benefited from this extra treatment.

The researchers found significant variations in treatment depending on geographic location. They also noted that younger women were more likely to have aggressive treatment while older women tended to have conservative treatment.

How Does This Affect You?

The increased incidence of DCIS from 1992 to 1999 does not mean more women are developing this condition. Rather, it suggests more frequent diagnoses of existing cases though mammograms and early biopsies. While treatment for DCIS has apparently changed over this period of time, no consistent treatment has emerged. While some cases are treated aggressively (mastectomy, axillary dissection) others are treated more conservatively (lumpectomy without radiation therapy). And the wide geographical variation suggests that many of these treatment decisions are based on something other than medical need. This should come as no surprise, since many studies have shown that this highly variable approach to treatment is true for many other conditions besides breast cancer.

Because DCIS is a relatively new diagnosis, doctors are still developing an understanding of its progression and the appropriate treatment strategies. Since DCIS is, by definition, restricted to the breast ducts, the risk of spread should be significantly lower than for invasive breast cancers, which have already penetrated through the ducts at the time of diagnosis. This would suggest that conservative treatment ought to be adequate for most cases of DCIS. During surgery, however, some doctors may undertake more aggressive treatment if they feel there is a chance the cancer has already spread. Until more research conclusively shows that it is just as safe to use conservative methods to treat DCIS, surgeons will continue to rely on other factors besides science to make their treatment decisions.

If you’ve been diagnosed with DCIS, or any medical conditions for that matter, do not underestimate the influence you have over your own treatment plan. You should not hesitate to talk to your doctor about the available treatment options, and the potential risks and benefits of each. Even though there may not currently be a well accepted course of action, you and your doctor can still determine the most appropriate strategy for you, based on a healthy balance of the available research, your physician’s good judgment, and your own personal values.