THE CURRENT MANAGEMENT OF DCIS.
MONICA MORROW, MD, PROFESSOR OF SURGERY
Prior to the use of screening mammography, DCIS was infrequently diagnosed. Clinicalpresentations of DCIS (masses, nipple discharge, Paget’s disease) accounted for only
about 2% of cancers. Currently, in populations which are screened regularly,
approximately 30% of new cancer diagnoses are DCIS. This has led to concern thatmammography may lead to the overdiagnosis of DCIS, and that some DCIS detected inthis way may never become clinically relevant. Since there is no information on thenatural history of mammographically detected, untreated DCIS we studied a cohort of41,837 women followed for 371,477 women years to examine the relationship between
risk factors for DCIS and invasive cancer. During the study period, 1520 cancers
developed. DCIS and invasive cancer shared common risk factors, and the magnitudeof risk for both conditions was similar (1) These findings suggest that DCIS and invasivecancer are part of the same disease process.
The initial treatment for DCIS was mastectomy.

Mastectomy results in long-term

survival for 96% - 99% of women, regardless of the size, grade, or histologic type ofDCIS. However, in an era of breast conserving therapy for invasive carcinoma, it isdifficult to justify the routine use of mastectomy for DCIS. Nonrandomized studies of thetreatment of DCIS with excision and radiation (RT)have reported 10-year local
recurrence rates of approximately 15%(2). Half of the local recurrences are invasive
carcinoma, and the 15-year cause specific mortality is 4% with this approach. Otherstudies have questioned the need for RT to be routinely used for the treatment of DCIS.
Silverstein et al (3) devised the Van Nuys Prognostic Index (VNPI), in which size, grade,and margin width were each assigned a score of 1 to 3. Using retrospective data, it wasdetermined that patients with the lowest VNPI scores (3 or 4) did not benefit from RT. In
an update of this work, it was suggested that only margin status was important indetermining the need for RT, and that patients with margins of 1cm or more did notbenefit from RT (4). These studies suffer from all the potential pitfalls of retrospectivedata collection over a long time period. Two prospective, randomized trials have directly
addressed the benefits of RT in DCIS. The first, NSABP B17, randomized 814 womento treatment with excision to negative margins (defined as tumor filled ducts not touchingan inked surface) or excision and RT. After 90 months of follow up, the use of RT
reduced the incidence of invasive recurrence from 13.4% to 3.9% (p=0.00005) and theincidence of recurrent DCIS from 13.4% to 8.2% (p=0.007)(5). Subset analysis failed toidentify a group who did not benefit from RT, with patients with low-grade, noncomedo
DCIS with negative margins having a 7% absolute reduction in recurrences at 8 years(6). A second trial from the EORTC (7) randomized more than 1000 women to treatment
with excision alone or excision and RT. After 4 years, a 7% reduction in recurrences
was seen in the RT group. These randomized trials would suggest that although themagnitude of benefit obtained with RT varies, all patients with DCIS will have the risk oflocal failure reduced with this treatment. An additional randomized trial (NSABP B21)
has shown that the addition of tamoxifen to excision and RT reduces the risk of both
ipsilateral and contralateral breast events from 13.4% to 8.2% at 4 years(8). Controversy
has recently arisen regarding the use of sentinel node (SN) biopsy in DCIS.
Immunohistochemistry of the SN is reported to be positive in up to 10% of cases of DCIS.
However, extensive data from axillary dissection demonstrates that nodal metastases
are present in only 1% - 2% of mammographically detected DCIS, and long-term survival
rates of 98% -99% are not compatible with a 10% incidence of nodal metastases. We
reserve sentinel node biopsy in DCIS for patients with large areas of DCIS who requiremastectomy, where the risk of invasion is high and it is not possible to perform SNbiopsy as a second stage procedure.

References:1.

Gapstur S, Sellers TA Morrow M. Hormone replacement therapy and risk ofbreast cancer with favorable histology: results of the Iowa Women’s Health Study.
JAMA 1999;281:2091-2097.

2.

Morrow M, Schnitt SJ, Harris JR. Ductal carcinoma in situ and microinvasivecarcinoma. Diseases of the Breast 2nd edition. Harris JR, Lippman ME, Morrow M,
Osborne CK eds. Lippincott Williams & Wilkins. Philadelphia 2000 p. 383-402.

3.

Silverstein MJ, Lagios MD, Craig PH et al. A prognostic index for ductal
carcinoma ion situ of the breast. Cancer 1996;77:2267-2274.

4.

Silverstein MJ, Lagios MD, Groshen S et al. The influence of margin width on
local control of ductal carcinoma in situ of the breast. N Engl J Med.
1999;340:1455-1461.

5.

Fisher B, Dignam J, Wolmark N et al. Lumpectomy and radiation therapy for thetreatment of intraductal breast cancer: Findings from the National Surgical
Adjuvant Breast and Bowel Project B17. J Clin Oncol 1998;16:441-452.

6.

Fisher ER, Dignam J, Tan-Chiu E et al. Pathologic findings from the National
Surgical Adjuvant Breast and Bowel Project (NSABP). Eight year update ofprotocol B17: intraductal carcinoma Cancer 1999;86:429-438.

7.

Julien JP, Bijker N, Fentiman I et al. Radiotherapy in beast conserving treatmentfor ductal carcinoma in situ: First results of EORTC randomized phase 3 trial
10853. Lancet 2000;355:528-533.

8.

Fisher B. Dignam J, Wolmark N et al. Tamoxifen in treatment of intraductal
breast cancer: National Surgical Adjuvant Breast and Bowel Project B24
randomized controlled trial. Lancet 1999;353:1993-2000.