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Breast Cancer




Screening

Mammography in women over 50 is the screening test that lowers mortality the most. Mammography begins at age 50 and is not routinely done once over 75. 

BRCA genetic testing is not routinely done. BRCA gene is likely to be positive if there is a family history of breast cancer or increased risk of ovarian cancer. 

Diagnosis

A positive mammography is followed by sentinel node biopsy. Sentinel node = the first lymph node that a dye/ tracer injected into the operative field reaches. If biopsy sample is positive for cancer it is tested for markers including ER (estrogen receptor), PR (progesterone receptor), HER2/neu. A positive biopsy result is followed by axillary lymph node dissection. 

Prevention

Tamoxifen is given if 2 or more first-degree relatives have breast cancer. It reduces risk of breast cancer by 50% and is started at age 40. 

Treatment

Surgical removal of the tumor is best done with lumpectomy with radiation treatment. Another option is modified radical mastectomy. 

Hormone inhibition therapy is added if ER+ or PR+ breast cancer. It works best if both estrogen and progesterone receptor positive. Tamoxifen is commonly used but has many adverse effects including increased risk of DVTs, increased risk of endometrial cancer, and hot flashes. This is because Tamoxifen is not only an estrogen antagonist but also an agonist at certain tissues. Aromatase inhibitors are another option and they are estrogen antagonists. Because they do not act as estrogen agonists they have fewer adverse effects. However, they increase the risk of osteoporosis because they block estrogen receptors in the bone. 

Adjuvant chemotherapy is added if the cancer has spread to the axilla or if it is larger than 1 cm. Chemotherapy works best for patients who are still menstruating because these patients are less likely to have their cancer controlled with the hormonal inhibition therapy.  

Immunotherapy is added if the cancer is HER2/neu positive. It is most helpful if the cancer is metastatic. Immunotherapy here means monoclonal antibodies (Trastazumab and Pertuzumab). Trastuzumab is associated with cardiac-toxicity.  


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