DCIS: To radiate or not to radiate?

Last Modified: August 29, 2007

Dear OncoLink "Ask The Experts,"
I have had the removal of a 1/2 centimeter, stage 0, DCIS (ductal carcinoma in situ) from my left breast. The second biopsy was clear of cancer in the surrounding area.

Is radiation necessary, or can I take a chemo drug like tamoxifen for 5 years instead and be considered quite safe from a return of cancer?

I am 60 years old and in excellent health. I would appreciate your advice.

Lawrence J. Solin, MD, FACR, Professor of Radiation Oncology at the University of Pennsylvania, responds:

Ductal carcinoma in situ (DCIS) is a form of non-invasive breast disease in which cancer-like cells are present within the ductal system of the breast, but do not invade through the ducts. DCIS is often discovered in the asymptomatic patient on routine screening mammography.

The management of DCIS continues to be a matter of some controversy. Randomized trials have demonstrated that the addition of radiation after so-called lumpectomy reduces the rate of local recurrence by about one-half, including a reduction in the risk of invasive local recurrence. Trying to identify low- risk patients for whom radiation can be omitted remains a subject of great interest. The risk of local recurrence is generally defined based on the size of the lesion, margins of resection, age of the patient, and pathologic features of the DCIS lesion. Prospective research trials are currently attempting to identify patients for whom radiation can be omitted.

Tamoxifen may also reduce the risk of recurrence, not only in the treated breast but also in the contralateral breast. However, no study has yet demonstrated that tamoxifen can be used as a substitute for radiation treatment.

Given the many issues involved, most patients with DCIS benefit from discussion of the potential management options with a surgeon, radiation oncologist, and medical oncologist.