Current controversies in ductal carcinoma in situ of the breast:: Summary from the lynn sage breast cancer symposium

Ductal carcinoma in situ (DCIS) of the breast is a heterogeneous group of lesions with diverse malignant potential and a range of controversial treatment options. It is the most rapidly growing subgroup in the breast cancer family, with an estimated 53,000 new cases diagnosed in the United States during 2002. Most new cases are nonpalpable and are discovered by mammography. Therapy for DCIS ranges from simple excision to various forms of wider excision (segmental resection, quadrant resection, and so forth), all of which might or might not be followed by radiation therapy. If breast preservation is not an option, then mastectomy, with or without immediate reconstruction, is generally performed. Because DCIS is a heterogeneous group of lesions rather than a single entity and because patients have a wide variety of personal needs that must be considered during treatment selection, it is obvious that no single approach will be appropriate for all forms of the disease or for all patients. At the present time, treatment decisions are based on a variety of measurable parameters (tumor extent, margin width, nuclear grade, comedotype, necrosis, age, and so forth). As our knowledge of DCIS has evolved during the last decade, the treatment decision-making process has become much more complex and controversial. There are numerous ongoing prospective randomized trials that are attempting to simplify the treatment-selection process. Only two have been published, one performed by the National Surgical Adjuvant Breast Project (NSABP) (protocol B-17) and one performed by the European Organization for Research and Treatment of Cancer (EORTC) (protocol 10853). The results of NSABP B-17 were updated in 1995, in 1998, in 1999, and in 2001. In the NSABP B-17 study, more than 800 patients with DCIS excised with clear surgical margins were randomized into two groups: excision only versus excision plus radiation therapy. The main endpoint of the study was local recurrence, invasive or noninvasive (ie, DCIS). After 12 years of followup, there was a statistically significant decrease in local recurrence of both DCIS and invasive breast cancer in patients treated with radiation therapy. The overall local recurrence rate for patients treated by excision alone was 32% at 12 years. For patients treated with excision plus breast irradiation, it was 16%, a 16% difference in favor of those treated with radiation therapy or a relative benefit of 50%. These updated data led the NSABP to stand by their 1993 position and to continue to recommend postoperative radiation therapy for all patients with DCIS who chose to save their breasts. The early results of B-17 in favor of radiation therapy for patients with DCIS led the NSABP to perform protocol B-24. In this trial, more than 1,800 patients with DCIS were treated with excision and radiation therapy and were then randomized to receive either tamoxifen or placebo. After 7 years of followup, 11% of patients treated with placebo had experienced local recurrence, but only 8% of those treated with tamoxifen had experienced local recurrence. The difference, although small, was statistically significant for invasive local recurrence but not for noninvasive (DCIS) recurrence. The EORTC results were published in The Lancet in 2000. This study was essentially identical to B-17 in design and included more than 1,000 patients. At 6 years of followup, 11% of patients treated with excision plus radiation therapy had experienced local recurrence, compared with 20% of patients treated with excision alone, results similar to those obtained by the NSABP at the same point in their trial. In distinction to the Presented at the 4th Annual Lynn Sage Breast Cancer Symposium, Chicago, IL, October–November 2002.