The management of ductal carcinoma in situ (DCIS) consists of coordinated medical care from diagnostic radiologists, surgeons, pathologists, and radiation oncologists.
More than 90% cases of DCIS are diagnosed through screening mammography. A pathology diagnosis from a biopsy is usually needed if the mammogram is suggestive of DCIS.
Once the diagnosis of DCIS is established, patients should be evaluated for breast-conserving surgery. The majority of DCIS patients in the United States are treated with breast-conserving surgery. However, mastectomy will be necessary if the tumor presents in two or more quadrants of the breast, or if the patient has contraindication for post-surgical radiotherapy. Patients with repeated positive surgical margins during conserving surgery should also consider mastectomy. Unlike the treatment for invasive carcinoma of the breast, surgical exploration of the axilla for lymph node dissection is usually not needed for DCIS, although patients with this pre-cancerous disease carry a 3 to 13% risk of axillary lymph node invasion.
Currently, radiation treatment to the breast is routinely administered after breast-conserving surgery, although methods of identifying patients who may not need radiation after local excision of the tumor are being studied. Most patients receive 5 weeks of external beam radiotherapy (~50 Gy of radiotherapy) delivered once per day, five days a week. Some radiation oncologists may also recommend a few more fractions of radiation to the tumor bed following the primary treatment. Post-surgery radiation halves the chance of the recurrence of cancer in the same breast; however, it does not change the overall post-surgery survival rate.
After surgery and radiotherapy, certain groups of patients with DCIS may benefit from hormonal treatment. These cases include estrogen-receptor-positive DCIS, and patients at high risk of recurrence or developing another primary breast cancer in the contralateral breast. The most common hormonal agent used for this prophylactic treatment is tamoxifen. Patients should discuss such treatment with their oncologists after surgery and radiotherapy.
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