Patients are confused, and no wonder—because doctors don’t even agree on the name, much less on how aggressively to treat the breast condition officially known as ductal carcinoma in situ (DCIS). Some women with DCIS wind up doing nothing, while others opt for extensive surgery and/or years of pharmacological treatment. Here’s why this confounding condition presents such a dilemma…

DCIS, which develops when genetic mutations occur in the DNA of cells within a milk duct, is generally considered the earliest form of breast cancer. Also called stage 0 breast cancer, it is noninvasive, meaning that the abnormal cells have not spread beyond the milk duct to invade surrounding breast tissue. Because it seldom produces symptoms, it usually is discovered during a routine mammogram. In itself, DCIS is not life-threatening—in fact, some doctors refer to it as precancer rather than cancer.

The concern, of course, is that if these cancer cells do develop the ability to break down the wall of the milk duct and grow, then they will have become invasive cancer—with the potential to spread and be fatal. The local treatments offered to DCIS patients are similar to those for patients with invasive breast cancer. For some women, this may be overtreatment, as their DCIS cells may never develop the capacity to invade or spread. Problem is, as yet there’s no way to foretell whose disease will become invasive and whose won’t.

For insights, HealthyWoman interviewed Irene Wapnir, MD, chief of breast surgery at the Stanford Cancer Institute and a leading breast cancer researcher. Her recent analysis of two long-term studies on the efficacy of various treatments helped bring increased clarity to the question of how to handle DCIS.

An estimated 60,000 US women are diagnosed with DCIS each year. If you are ever among them, remember that DCIS is not an emergency, so you can safely take several weeks or more to investigate your options. Here are the treatments—from the least to the most aggressive—to discuss with your oncologist…

Lumpectomy (surgical removal of the abnormal tissue and a surrounding margin of healthy tissue). This preserves the breast, allows a quick recovery and has a minimal effect on appearance. In Dr. Wapnir’s study, which followed patients for an average of about 15 years, 19% of DCIS patients who received lumpectomy alone developed subsequent invasive breast cancer. Dr. Wapnir said that a DCIS patient over age 70 who also has another medical problem that is potentially life-threatening might consider lumpectomy alone rather than lumpectomy plus radiation and tamoxifen (described below).

Lumpectomy plus radiation. The goal of radiation is to kill any lingering cancer cells. Compared with lumpectomy alone, the addition of radiation reduced breast cancer recurrence risk by more than half, Dr. Wapnir found. Also, radiation potentially allows for narrower margins—for instance, the surgeon might remove a 1-mm margin of healthy tissue rather than the 2-mm to 5-mm margin recommended with lumpectomy alone—thus allowing superior cosmetic results. Downside: Radiation can have long-term side effects at the treatment site, such as skin darkening or thickening and mild shrinkage of breast tissue.

Lumpectomy, radiation and tamoxifen. A “triple therapy” that includes several years of use of the oral drug tamoxifen is appropriate for patients whose DCIS is determined to be hormone receptor positive. The drug blocks the action of estrogen, a hormone that promotes cancer cell growth. Dr. Wapnir found that, compared with lumpectomy plus radiation, triple therapy reduced tumor recurrence by another 32%. Bonus: Tamoxifen protects both breasts, not just the DCIS-affected breast…and it reduces the number of new cancers by half, Dr. Wapnir said.

Single mastectomy. Surgically removing the breast with DCIS eliminates nearly all the risk of developing invasive cancer in that breast and also eliminates the need for radiation. However, women may consider mastectomy more disfiguring than lumpectomy…and there is no known survival advantage to mastectomy. Dr. Wapnir said that mastectomy makes most sense for women whose DCIS is large (more than 5 cm) or in multiple sites in the breast. Alternatively, she added, some women may choose mastectomy due to personal preference or because they wish to avoid radiation or tamoxifen therapy

Double mastectomy. According to a study from the University of Minnesota, the number of patients opting to remove the healthy breast as well as the DCIS-affected breast has soared since 1998. For women at extremely high risk for invasive breast cancer—for instance, because they carry a BRCA breast cancer gene mutation—it may be reasonable to consider this approach to prevention. But otherwise, Dr. Wapnir said, physicians should take care not to foster patients’ fears by overemphasizing the dangers of DCIS and thus subjecting women to double mastectomy for a condition that may never become life-threatening.

Bottom line: For most DCIS patients, breast-conserving lumpectomy plus radiation (and tamoxifen, when appropriate) would be Dr. Wapnir’s treatment of choice. In her study, fewer than 1% of the 2,612 participants who underwent lumpectomy, with or without radiation and/or tamoxifen, ended up dying as a result of breast cancer recurrence—a very reassuring statistic.

For help making treatment decisions: A second opinion is always a good idea. To find a National Cancer Institute-designated comprehensive cancer center, check