Porth's Essentials of Pathophysiology, 4e

1046

Genitourinary and Reproductive Function

U N I T 1 1

The prognosis for women with breast cancer is related more to the extent of nodal involvement than to the extent of breast involvement. Greater nodal involvement requires more aggressive postsurgical treatment, and many cancer specialists believe that a diagnosis of breast cancer is not complete until dis- section and testing of the axillary lymph nodes have been accomplished. A newer technique for evaluat- ing lymph node involvement is a sentinel lymph node biopsy. A radioactive substance or dye is injected into the region of the tumor. In theory, the dye is carried to the first (sentinel) node to receive lymph from the tumor. This would therefore be the node most likely to contain cancer cells if the cancer has spread. If the sentinel node biopsy is positive, more nodes are tested. If it is negative, further lymph node evaluation may not be needed. Systemic therapy refers to the administration of chemotherapy, biologic therapy, or hormonal therapy. Neoadjuvant therapy is given before surgery to shrink the tumor and make surgical removal more effective. Adjuvant therapy is given after surgery to women with and without detectable metastatic disease. The goal of this therapy depends on nodal involvement, menopausal status, and hormone receptor status. Systemic adjuvant therapy has been widely studied and has demonstrated benefits in reducing rates of recurrence and death from breast cancer. 61 Biologic therapy, using the drug trastu- zumab (Herceptin), is used to stop the growth of breast tumors that express the HER2/neu receptor on their cell surface. The HER2/neu receptor binds an epidermal growth factor that contributes to cancer cell growth. 63 Trastuzumab is a recombinant DNA-derived mono- clonal antibody that binds to the HER2/neu receptor, thereby inhibiting proliferation of tumor cells that over- express the receptor gene. 63 Hormone therapy is used to block the effects of estro- gen on the growth of breast cancer cells. Tamoxifen is a nonsteroidal antiestrogen that binds to estrogen recep- tors and blocks the effects of estrogens on the growth of malignant cells in the breast. Studies have shown decreased cancer recurrence, decreased mortality rates, and increased 5-year survival rates in women with estro- gen receptor–positive tissue samples who have been treated with the drug. Aromatase inhibitors block the enzyme that converts androstenedione and testosterone to estrogen in the peripheral tissues. This reduces the circulating estrogen levels in postmenopausal women and is becoming the most effective adjuvant therapy for women with early-stage breast cancer. 64 Autologous bone marrow transplantation and peripheral stem cell transplantation are experimental therapies that may be used for treatment of advanced disease or in women at increased risk for recurrence. Paget Disease Paget disease accounts for 1% of all breast cancers. 57,58 The disease presents as an eczematoid lesion of the nipple and areola. Paget disease usually is associated with an infiltrating, intraductal carcinoma. When the

lesion is limited to the nipple only, the rate of axillary metastasis is approximately 5%. Complete examina- tion is required and includes a mammogram and biopsy. Treatment depends on the extent of spread.

SUMMARY CONCEPTS

■■ The breast contains alveolar glands and ducts that are lined with epithelial tissue that may give rise to benign and malignant lesions. ■■ Benign conditions include inflammatory disorders (mastitis, mammary duct dysplasia, and fat necrosis) and benign epithelial lesions (nonproliferative lesions, proliferative lesions without atypia, and proliferative lesions with atypia). Some benign conditions, such as proliferative lesions, may predispose to malignant disease, and others, such as fibrocystic changes and fat necrosis, may present with a mass and signs that resemble malignant disease. ■■ Breast cancer is a significant cause of death for women. Some inherited breast cancers are associated with mutations in breast cancer genes BRCA1 and BRCA2. The combination of clinical breast exam and mammography afford women the best opportunity for detection of breast cancer which allows for earlier treatment and improved outcomes. The choice of treatment, which includes surgical resection, radiation, and chemotherapy, depends on the stage of the disease. 1. Most oral contraceptive agents use low doses of estrogen and progestin to prevent conception. A. Use Figures 40-5 and 40-6 to explain how these oral agents prevent ovulation and pregnancy. 2. A 32-year-old woman has been told that the report of her annual Pap test revealed the presence of mild cervical dysplasia. A. What questions should this woman ask to become informed about the significance of these findings? B. Cervical cancer is often referred to as a sexually transmitted disease. Explain. C. What type of follow-up care would be indicated? R E V I EW E X E R C I S E S