Breast Cancer

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Treating Breast Cancer TOPICS

Treatment of non-invasive (stage 0) breast cancer

Stage 0 includes lobular carcinoma in situ (LCIS) and ductal carcinoma in situ (DCIS), which are treated very differently.


Since this is not a true cancer or pre-cancer, no immediate or active treatment is recommended for most women with LCIS. But because having LCIS increases your risk of developing invasive cancer later on, close follow-up is very important. This usually includes a yearly mammogram and a clinical breast exam. Close follow-up of both breasts is important because women with LCIS in one breast have the same increased risk of developing cancer in either breast. Although there is not enough evidence to recommend routine use of magnetic resonance imaging (MRI) in addition to mammograms for all women with LCIS, it is reasonable for these women to talk with their doctors about their other risk factors and the benefits and limits of being screened yearly with MRI.

Women with LCIS may also want to consider taking tamoxifen or raloxifene (Evista) to reduce their risk of breast cancer or taking part in a clinical trial for breast cancer prevention. For more information on drugs to reduce breast cancer risk see our document, Medicines to Reduce Breast Cancer Risk. They might also wish to discuss other possible prevention strategies (such as reaching an optimal body weight or starting an exercise program) with their doctor.

Some women with LCIS choose to have a bilateral simple mastectomy (removal of both breasts but not axillary lymph nodes) to reduce their risk of breast cancer, especially if they have other risk factors, such as a strong family history. A woman also may consider immediate or delayed breast reconstruction.


In most cases, a woman with DCIS can choose between breast-conserving surgery (BCS) and simple mastectomy. BCS is usually followed by radiation therapy. Lymph node removal (most often a sentinel lymph node biopsy) is not always needed. It may be done if the doctor thinks that a woman with DCIS may also have an area of invasive cancer. The risk of an area of DCIS containing invasive cancer goes up with tumor size and nuclear grade. Many doctors will do a sentinel lymph node biopsy if a mastectomy is done for DCIS. This is because if an area of invasive cancer is found in the tissue removed during a mastectomy, the doctor won’t be able to go back and do a sentinel lymph node procedure later, and so may have to do a full axillary lymph node dissection.

Radiation therapy given after BCS lowers the chance of the cancer coming back in the same breast (as more DCIS or as an invasive cancer). BCS without radiation therapy is not a standard treatment, but might be an option for certain women who had small areas of low-grade DCIS that were removed with large enough cancer-free surgical margins. But most women who have BCS for DCIS will require radiation therapy.

Mastectomy may be necessary if the area of DCIS is very large, if the breast has several areas of DCIS, or if BCS cannot completely remove the DCIS (that is, the BCS specimen and re-excision specimens have cancer cells in or near the surgical margins). Women having a mastectomy for DCIS may choose to have reconstruction immediately or later.

If the DCIS is estrogen receptor−positive, treatment with tamoxifen for 5 years after surgery can lower the risk of another DCIS or invasive cancer developing in either breast. Women may want to discuss the pros and cons of this option with their doctors.

Last Medical Review: 09/11/2013
Last Revised: 01/31/2014