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UCLA Breast Center

Revlon/UCLA Breast Center: Westwood Location, 200 UCLA Medical Plaza, Los Angeles

Breast Cancer Prevention

  • Who are candidates for breast cancer prevention?
    What is the term "breast cancer prevention" referring to?

    The term breast cancer prevention in general is applied to the interventions that may stop the disease from occurring. Both medications and surgery have been used for breast cancer prevention.

    Because of the side effects of the medications and the invasive nature of the surgery, they should only be offered to individuals with high risk for breast cancer. The women included in this group are those who have many family members with breast cancer and/or ovarian cancer and those who are carriers of a mutated BRCA gene. Women with previous breast biopsies showing the conditions such as atypia or lobular carcinoma in situ, may also be considered for preventative intervention.
  • Are there any effective means that is fail proof for breast cancer prevention?
    Unfortunately, there is no prevention that can absolutely block breast cancer from occurring. One might assume that removal of both breasts would prevent a woman from ever developing breast cancer. In reality, prophylactic mastectomies may reduce the risk of developing breast cancer by approximately 90%, but not the expected 100%. Prevention using medicines reduces the incidence of breast cancer by approximately 50% in those carrying a high risk for breast cancer. Of the two methods, surgery is radical but more effective.
  • Are there any medicines capable of reducing breast cancer risk?
    Of the many drugs that are tested only two have proven effective for breast cancer prevention. Tamoxifen is the first one used for breast cancer prevention and is effective in both pre- and post-menopausal women. This drug has been used for more than 3 decades in breast cancer treatment. Raloxifene is another one that has recently been shown to be as effective as tamoxifen in preventing invasive breast cancer in post-menopausal women. Both tamoxifen and raloxifene are from the same family of drugs, with raloxifene being newer.
  • To what extent is the breast cancer risk reduced by the medicine treatment?
    Breast cancer risk reduction by tamoxifen or raloxifene was reported in the range of 50 to 66 % in women with high risk for developing breast cancer. The risk is usually calculated from a formula called the Gail model, based on women's age, their family history of breast cancer in first degree relatives, personal history of breast biopsies and atypia or lobular carcinoma in situ found by biopsy, age at menarche and first live birth. Recently, having dense breasts on mammography was also added into the risk model.
  • Is there any measurement that may predict the effectiveness of the medication?
    Thus far, there is no way to predict who may specifically benefit from these medicines. There are studies looking for surrogate markers in the blood that may predict the individuals who will benefit from the medication.
  • What are the side effects of tamoxifen and raloxifene?
    Most of the side effects of tamoxifen and raloxifene are mild. The common side effects are hot flashes, vaginal discharge and/or bleeding. The latter problem could be harmless or a sign of a serious condition. Skin rashes and hair loss are uncommon and when they occur, are mild in nature.

    Probably the most serious side effect of tamoxifen is blood clotting, which can be life-threatening such as deep venous thrombosis (DVT - clots in the veins, usually the leg veins), pulmonary embolism (clots in the lung veins) and stroke. DVT more frequently occurs in the legs. One may experience leg swelling, calf pain and redness at the involved area. When untreated, DVT might lead to pulmonary embolism, although pulmonary embolism and stroke could happen without DVT. Symptoms associated with pulmonary embolism are shortness of breath, chest pain and cough.

    The chances of having a stroke are somewhat higher if you are taking these medicines, which could manifest in many ways, including, but not limited to, weakness, numbness, difficulty of walking or talking, etc.

    Endometrial cancer (cancer of the internal lining of the uterus) is another serious uncommon side effect of tamoxifen. The first sign may be vaginal bleeding/discharge, and menstrual irregularities. Patients who did not have hysterectomy (uterus removal) should have regular check-ups with their gynecologists while taking tamoxifen. Prompt evaluation of any of these symptoms usually provides good outcome, as they can lead to an early diagnosis of uterine cancer.

    Impaired vision because of cataracts (deposits of opaque substances in the eye lenses) could be another side effect of tamoxifen.

    Recently, a large multicentric study, enrolling almost 20,000 post-menopausal women, compared tamoxifen and another drug raloxifene in breast cancer prevention. The study showed that both medications are similar in reducing breast cancer incidence with some differences in their side effects. Raloxifene use was associated with fewer cases of uterine cancer than tamoxifen; however the difference was not significant. Episodes of stroke occurred equally in patients taking either medicine. DVT and pulmonary embolism (clotting of the legs and lungs) were more common in the tamoxifen group. The group treated with raloxifene had lower incidence of cataracts and cataract surgery. While tamoxifen is more suitable for both young and older women, raloxifene is limited to postmenopausal women.
  • How are tamoxifen or raloxifene being given for breast cancer prevention?
    For breast cancer prevention, the recommendation is to take 20 mg of tamoxifen or 60 mg of raloxifene by mouth every day for 5 years.
  • What types of surgery are being used for breast cancer prevention?
    Breast removal has been used in breast cancer prevention and the procedure is called prophylactic mastectomy. Variations of mastectomy such as subcutaneous mastectomy, skin sparing simple mastectomy and simple mastectomy have all been employed for this purpose. In the subcutaneous mastectomy, skin envelope and nipple areolar complex (NAC) with a small rim of breast tissue are preserved. The skin sparing mastectomy preserves only the skin envelope but not the NAC. Either subcutaneous or skin sparing mastectomies can be performed when reconstruction is part of the same procedure. In the absence of immediate reconstructive procedure, simple mastectomy, removing the skin and the NAC, is the procedure of choice.
  • To what extent is the breast cancer risk reduced by prophylactic mastectomy?
    The risks of future breast cancer are reduced by at least 90% in women who had bilateral prophylactic mastectomies. There is no surgical procedure capable of removing 100% of the breast tissue, therefore the prevention is not 100% either.
  • Who are candidates for prophylactic mastectomy?
    Prophylactic mastectomy may occur in the following scenarios: 
          1. Removal of both breasts in women without cancer diagnosis;
          2. Removal of one healthy breast in women with breast cancer found in the other breast.

    For both groups the decision should be made only after thorough discussion and careful consideration as this is a radical extirpative procedure. Bilateral prophylactic mastectomies (removal of both breasts) may be considered in women who have not been diagnosed with breast cancer if: 

         a. previous breast biopsies showed atypical ductal or lobular hyperplasia, especially if there is a strong family history of
             breast cancer;
         b. there is history of breast cancer and/or ovarian cancer in multiple blood related relatives, particularly mother or sister,
             who were diagnosed at young age and with cancer found in both breasts, or who has a known condition of BRCA1 or 
             BRCA2 mutation (genetic mutation that predisposes one to breast and/or ovarian cancer development);
         c. individual with many biopsies in whom breast exam is difficult and mammography shows dense breasts which are 
            impossible to evaluate and to follow.

    A discussion regarding this decision should take place with an experienced surgeon, familiar with breast cancer diagnosis and treatment. A reconstructive option should be considered at the same time. As there is no urgency for the decision making, open and frank discussions between doctor and woman, among the family members, an additional surgical opinion and psychological counseling are all helpful to assist the patient in making the right choice. Prophylactic mastectomy to remove the healthy breasts can also be considered in patients who were undergoing breast cancer surgery for the other breast when: 
        a. the healthy breast has diffuse microcalcifications on the mammography, with uncertain clinical significance;
        b. there is lobular cancer at the other side;
        c. the normal breast is difficult to be followed with mammography and by clinical exam;
        d. other high risk situations, such as a strong family history, young age at diagnosis (< 40 years old), and BRCA1 or BRCA2
            mutations are present;
        e. patient wishes to have the procedure done.

Helena Chang, M.D., Ph.D. and Raquel Prati, M.D.

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