Overview of Treatment

Monica Morrow, MD; Temple University School of Medicine

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Preventing local recurrence is a major goal in the treatment of DCIS and is an appropriate endpoint, as 70 percent of women surveyed indicate that risk of recurrence is the greatest factor influencing their treatment decisions.

The standard treatments in DCIS management are mastectomy, excision with radiotherapy, and excision alone; tamoxifen may or may not be used in conjunction with any of these therapies. Each of these treatments has approximately the same overall survival rate of 97 percent. Treatment is based on the fact that the presence of invasive cancer cannot be excluded reliably without complete excision of the lesion. Approximately 10 percent of DCIS cases diagnosed by core biopsy are later diagnosed as invasive cancer on removal of the entire lesion.

It has been suggested by retrospective studies that radiotherapy can be avoided if a large enough surgical operation is performed. However, 4 prospective randomized trials have demonstrated that RT significantly reduces the risk of local recurrence, and subsets of women who do not benefit from radiotherapy have not been reproducibly identified. Efforts to prospectively document that wide excision alone results in a high rate of local control for selected subsets of DCIS patients have been unsuccessful.

Mastectomy is indicated in the treatment of DCIS when the disease is too extensive to resect with a good cosmetic outcome, when there is an inability to achieve negative margins, and when radiotherapy is contraindicated in a high-risk patient. Because DCIS lacks the ability to metastasize, axillary surgery only is indicated because of the risk of unsampled invasive carcinoma. The risk of axillary recurrence in DCIS is extremely low, and the routine use of sentinel node biopsy in DCIS cases is contraindicated.

DCIS, however, is a marker for increased risk of invasive carcinoma in both breasts, and the 15-year risk of new cancer in a previously diagnosed DCIS patient is the same as the 5-year risk of local DCIS recurrence. The use of tamoxifen to treat DCIS has met with mixed results, but studies indicate that the benefits of tamoxifen are limited to women with estrogen receptor (ER)-positive DCIS.

Because patients are confused about the fundamental nature of DCIS, the perception of risk of recurrence and death as a result of DCIS is the same as these perceptions in invasive cancer. Reliable predictors of biologic behavior, progression to invasive cancer, and local recurrence are needed to resolve the DCIS dilemma. Additionally, better methods to communicate risks and benefits of treat¬ment choices are needed. Physicians should frame discussions with their patients in terms of complete diagnosis and the prevention of invasive cancer.