Case #1 Answers:
Ductal carcinoma in situ comprises a group of heterogeneous proliferative lesions within the ducts of the breast with diverse malignant potential, with a range of treatment options. It’s a precursor lesion to invasive ductal cancer. A transition from a benign to a malignant epithelium.
It is estimated that approximately 55,000 new cases will be diagnosed in 2004. Its incidence is increasing and closely parallels the utilization of screening mammograms, which detects disease in asymptomatic individuals. DCIS represents 20-40 percent of all mammographically detected breast cancers.
May present as a palpable mass or more commonly as a mammographic abnormality (stippled micro calcifications) or rarely as bloody nipple discharge. Prior to 1985 DCIS commonly presented as a palpable mass.
By the characteristic mammographic finding sand tissue diagnosis. By sterotactic biopsy or excisional biopsy.
A variety of histologic types occur in DCIS depending on the architectural pattern. Solid, Cribriform, papillary and comedo types. The nuclear grading of these could be low, intermediate or high and again with or without necrosis in the comedo type. Some classify them as noncomedo and comedo types.
The comedo variant has been associated with higher proliferative rates, over expression of Her-2/neu, necrosis and higher incidence of local reoccurrence after surgical excision.
In the past these patients had modified radical mastectomy and we now understand this was overkill. Today breast conservation therapy (lumpectomy) is the treatment of choice with the exception of extensive and diffuse DCIS or Multifocal DCIS.
Lumpectomy is followed by breast radiation and adjuvant tanoxifen.
Prior to 1985 DCIS was treated by surgery. In 1985, NSABP began a randomized clinical trial to see if lumpectomy with radiation therapy was more effective than lumpectomy alone. The results were reported in 1993. Women with lumpectomy alone developed ipsilateral breast cancer in 16.4 percent and among those who received lumpectomy plus radiation ipsilateral breast cancer developed in 7 percent. Radiation not only decreased the incidence of ipsilateral breast cancer, but also decreased the incidence of invasive breast cancer by 50 percent.
The presence of moderate/marked comedonecrosis was a significant independent factor for predicting local recurrence. Uncertain or involved margins was another predictive factor for recurrence.
No. DCIS by definition is intraductal carcinoma and hence metastasis does not occur, unless there is microinvasion.
NSABP – B-24 study that followed B-17 study compared the effects of Tamoxifen vs. Placebo following lumpectomy and radiation therapy with tamoxifen. The incidence of ipsilateral invasive breast cancer was reduced from 3.4 percent to 2.1percent contralateral breast cancer was reduced from 13 percent to 8.8 percent.
Currently adjuvant tamoxifen is prescribed for all patients with DCIS following lumpectomy and radiation unless specific contraindication exists. The best treatment for DCIS is in the process of evolution.