Dear cetn, Ductal Carcinoma in situ (DCIS) is confined within the lining of the ducts of the breasts and, unlike invasive breast cancer, does not metastasize (spread to other organs). If left untreated, however, DCIS can evolve into an invasive cancer. In addition, DCIS is frequently found in association with invasive breast cancer. The invasive component generally dictates the type of treatment recommended. Because of the risk for future spread of the cancer, adjuvant treatment with hormonal therapy and/or chemotherapy is often recommended to reduce that risk, presumedly by killing any microscopic deposits of tumor cells that may already be present elsewhere in the body. Radiation therapy is given to reduce the risk of recurrence in the breast or chest wall regions. Certain information such as the size of the invasive tumor, the grade of the tumor, lymph node status, estrogen receptor status etc. will influence decisions as to whether or not and what type of adjuvant treatment is recommended. Lymphovascular spaces refer to the blood and lymph circulation that flows through the breast. Presence of cancer cells in the lymphvascular spaces is another feature that may increase concern of cancer spread and therefore influence the recommedations for treatment. A medical oncologist should be able to fully discuss with you the risks and benefits of the various treatment options.