Breast cancer

Breast cancer:

  • Multidisciplinary approach: surgical oncology, radiation oncology, and medical oncology
  • Breast cyst: US -> aspirate
  • Breast mass: FNA or core needle biopsy -> excisional biopsy possibly needed
    • Any mass palpated on exam needs to be evaluated with biopsy!
      • Palpate mass -> Mammogram and/or US -> Biopsy (mass) or Aspirate (cyst)
    • Ductal carcinoma in situ (DCIS):
      • Pre-malignant condition – high risk of turning into cancer.
      • Tx: Breast-conserving therapy: wide excision lumpectomy (negative margins) + radiation
      • Estrogen receptor – positive: Hormone therapy – Tamoxifen: antiestrogen. Estrogen antagonist in breast cancer cells, prevents tumor growth (decreases the risk of local recurrence but not survival).
    • Lobular carcinoma in situ (LCIS):
      • Condition associated with an increased risk of breast cancer arising elsewhere in both breasts
      • Tx: Consider Tamoxifen. Close follow up and observation
    • Invasive ductal carcinoma or Lobular carcinoma:
      • Equivalent options with comparable overall survival:
        • Lumpectomy -> Radiation
          • If POSITIVE tumor margins after lumpectomy, must re-excise and radiate!
        • Mastectomy -> Radiation
          • Lower risk of local recurrence than lumpectomy! (very little tissue remains)
          • Mastectomy is recommended:
            • Tumors involving the skin, chest wall, ≥ 1 breast quadrant (large or multifocal tumors), inflammatory breast cancer, if contraindications to radiation (previous history of radiation), or patient’s preference.
              • Bilateral mastectomy: Familial breast cancer syndromes.
            • Chest wall radiation after mastectomy is recommended:
              • Tumor > 5cm
              • Positive surgical margins
              • Skin or chest wall involvement
              • Most patients with any positive axillary LNs.
              • Inflammatory breast cancer
                • Inflammatory breast cancer:
                  • Aggressive form of breast cancer that is characterized by thickened skin (peau d’orange) and dermal lymphatic invasion
                  • Breast conservation (lumpectomy) is generally considered inappropriate for local control.
                • Complete Axillary LN dissection:
                  • If sentinel LN biopsy is positive
                    • Sentinel LN biopsy involves injecting dye or tracer in the tumor and identifying which LN takes it up. The LN is then excised and assessed for metastasis.
                  • If axillary LNs are clinically involved

Step 1: Stage cancer using the Tumor, Node, Metastases (TNM) system – dictates treatment

  • Primary surgery: Lumpectomy or mastectomy to the breast and regional lymph nodes
    • With or without radiation
  • Consider adjuvant systemic therapy – based on primary tumor’s characteristics (tumor size, grade, number of involved LNs, receptor status: ER/PR/HER2)
    • Adjuvant systemic therapy:
      • Used to prevent or delay systemic recurrence for Stages I-III breast cancer
        • Stages in which the cancer is not metastatic and is potentially curable.
      • Adjuvant therapy is recommended for any patient with an infiltrating ductal or lobular cancer > 1cm or with POSITIVE LNs.
      • Examples: Medications – Tamoxifen, aromatase inhibitors, Trastuzumab, or chemotherapy
        • Estrogen/Progesterone receptor (ER/PR) – POSITIVE:
          • Hormonal Tx (receptors must be present for meds to work!):
          • Tamoxifen (for 5 years): anti-estrogen. Estrogen antagonist in breast cancer cells, prevents tumor growth. (Selective Estrogen Receptor Modulator: SERM)
            • ***The only FDA-approved drug for the primary prevention of breast cancer! (50% risk reduction!)***
            • ***Pre & Post-menopausal patients.***
          • Aromatase inhibitor: **Only used in POSTmenopausal pt**
            • Prevent conversion of adrenal androgens -> estrogen by targeting the aromatase enzymes in muscle and fat
            • Induces a menopausal state: Near elimination of estrogen production.
            • ADR – low estrogen (similar to menopause Sx):
              • Hot flashes
              • Loss of bone density
              • Sexual dysfunction
            • Tx ADR Sx: SSRIs, Calcium/Vitamin D, vaginal lubricants
            • More effective than Tamoxifen in preventing recurrence in POST-menopause pt
          • Chemotherapy may be needed in addition to Hormonal therapy (Tamoxifen vs Aromatase inhibitor)
            • ***Hormonal therapy is superior*** to chemotherapy for ER/PR POSITIVE tumors!
            • Add chemotherapy if patient’s disease progresses (metastasis).
        • Estrogen/Progesterone receptor (ER/PR) – NEGATIVE:
          • Chemotherapy – Paclitaxel, Docetaxel, Doxorubicin, Methotrexate, Vinorelbine, Capecitabine, 5-FU
        • Lymph node – POSITIVE: Chemotherapy (metastasize!)
        • HER2 – POSITIVE: Trastuzumab (Herceptin)
          • Monoclonal antibody against the HER2 receptor!
          • Overexpressed in about 10% of breast cancers
          • ***Poorer prognosis!***

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