Ductal Carcinoma In Situ
(DCIS)

Note that the current standard of care is generally lumpectomy, no node dissection then radiation. Based on the new data from NSABP B-24 it may be useful to add Tamoxifen as well. The B-24 study enrolled 1804 women diagnosed with DCIS (or DCIS plus Lobular Carcinoma In Situ (LCIS)) who had a lumpectomy and radiation therapy between 1990-1994. Half of the women were prescribed tamoxifen, 20 mg daily for five years, and half placebo. Researchers found that adding tamoxifen significantly reduced the incidence of all invasive and non invasive breast cancers at any site by 37%, from 13.4 percent in the placebo group (130 cases) to 8.2% in the tamoxifen-treated group (84 cases) In analyzing all invasive breast cancers, tamoxifen reduced the incidence over five years by 43%, from 7.2% in the placebo group (70 cases) to 4.1% in the tamoxifen-treated group (41 cases) (p=.004).

The study also shows that a woman who takes tamoxifen for five years of therapy has the greatest reduction (52%) in the incidence of new contralateral cancer (or CBTs). The cumulative incidence of all CBTs at five years was 3.4% in the placebo group compared with 2.0% in the tamoxifen group.  Tamoxifen reduced the rate of invasive CBTs by 37% but had an even greater benefit (78%) in reducing the number of non invasive CBTs (p=.02). Adverse events in the B-24 trial were similar to those observed in other NSABP trials evaluating tamoxifen.  The increase in endometrial cancer in B-24 was similar to that in he BCPT study. There were five endometrial cancers per 1000 women over five years, less than 1 percent. The incidence of other potentially serious events, including deep vein thrombosis and pulmonary emboli which was also less than 1%.  A follow up study showed that the benefits of Tamoxifen were restricted to those patients who were ERP + (77% of all ) in this group the reduction in new breast cancers was not just 37% it was 59%. (ERP - women had no benefit.) So it may now be appropriate to get hormone receptor status even in DCIS patients.

Also note that the standard of care is to not perform lymph node dissection (since the risk of lymph node spread if there is no microinvasion is thought to be close to 0%.) Recent studies using sentinel node biopsies and special staining of the nodes have found the risk of occult node spread may be as high as 8% as noted: " A significant expansion of the precision of sentinel lymph node diagnostics has occurred with the application of molecular and immunohistochemical markers to detect occult metastases. More intensive examination of these nodes occurs and more accurate staging results in DCIS patients with occult micrometastases to the regional lymphatic basin staged with greater precision. Our studies have shown that the seeming lack of microinvasion in the primary lesion does not prevent the presence of nodal disease. Data from  consecutive prospective series of 1,147 breast cancer patients who underwent lymphatic mapping are noted and all patients with a preoperative diagnosis of DCIS, regardless of size or pathologic staging, were evaluated with sentinel lymph node biopsy. Positive sentinel lymph nodes were found in 8.6% of the T0 or presumed pure DCIS patients"