Breast cancer is the most common cancer affecting women. It's estimated that 1 in 8 women in the United States will develop breast cancer during her lifetime. Male breast cancer accounts for 1% of all male cancers and less than 1% of all breast cancers. The 5-year survival rate for localized breast cancer has improved from 72% in the 1940s to 97% today because of early diagnosis and the variety of treatments now available. Lymph node involvement is the most valuable prognostic predictor. With adjuvant therapy, 70% to 75% of women with negative nodes will survive 10 years or more, compared with 20% to 25% of women with positive nodes.
Breast cancer may develop any time after puberty but is most common after age 50 (about 20% of cases occur in women under age 30 and more than 80% in women over age 50).
High risk factors
· Family history of breast cancer, particularly first-degree relatives (mother, sister, and/or maternal aunt)
· Positive tests for genetic mutations (BRCA 1 and BRCA 2)
· Long menstrual cycles
· Early menarche, late menopause
· Nulliparous or first pregnancy after age 30
· History of unilateral breast cancer or ovarian cancer
· Exposure to low-level radiation.
Low risk factors
· Pregnancy before age 20, history of multiple pregnancies
· Native American or Asian ancestry
Breast cancer occurs more commonly in the left breast than the right and more commonly in the outer upper quadrant. Slow-growing breast cancer spreads by way of the lymphatic system and the bloodstream, through the right side of the heart to the lungs, and eventually to the other breast, the chest wall, liver, bone, and brain.
Most breast cancers arise from the ductal epithelium. Tumors of the infiltrating ductal type don't grow to a large size, but metastasize early (70% of breast cancers).
Breast cancer is classified by histologic appearance and location of the lesion, as follows:
· adenocarcinoma—arising from the epithelium
· intraductal—within the ducts (includes Paget's disease)
· infiltrating—in parenchymal tissue of the breast
· inflammatory (rare)—overlying skin becomes edematous, inflamed, and indurated; reflects rapid tumor growth
· lobular carcinoma in situ—involves glandular lobes
· medullary or circumscribed—large tumor, rapid growth rate.
The descriptive terms should be coupled with a staging or nodal status classification system. The most commonly used staging system is the TNM (tumor size, nodal involvement, metastatic progress).
Signs and symptoms
· Painless lump or mass in the breast, breast pain
· Change in symmetry or size of the breast
· Change in skin—thickening, scaly skin around the nipple, dimpling, edema (peau d'orange), or ulceration
· Change in skin temperature (a warm, hot, or pink area)
· Unusual drainage or discharge
· Change in nipple (itching, burning, erosion, or retraction)
· Pathologic bone fractures, hypercalcemia
· Edema of the arm
· Axillary node enlargement
· Dilated blood vessels visible through the skin of the breast
· Arm edema
· Bone pain
A spontaneous discharge of any kind in a nonbreastfeeding, nonlactating woman warrants investigation.
Diagnostic test results
· Alkaline phosphatase levels and liver function tests uncover distant metastases.
· Hormonal receptor assay determines whether the tumor is estrogen- or progesterone-dependent.
· Mammography reveals a tumor that's too small to palpate.
· Ultrasonography distinguishes between a fluid-filled cyst and solid mass.
· Chest X-rays pinpoint metastases in the chest.
· Scans of the bone, brain, liver, and other organs detect distant metastases.
· Fine-needle aspiration and excisional biopsy provide cells for histologic examination may confirm the diagnosis.
· Lumpectomy—in many cases, radiation therapy is combined with this surgery
· Lumpectomy and dissection of axillary lymph nodes
· Quadrant excision
· Simple mastectomy—removes breast but not lymph nodes or pectoral muscles
· Modified radical mastectomy—removes breast and axillary lymph nodes
· Radical mastectomy (now seldom used)—removes breast, axillary lymph nodes, and pectoralis major and minor muscles
· Reconstructive surgery if no advanced disease
· Chemotherapy—adjuvant or primary therapy
· Tamoxifen (estrogen antagonist)—adjuvant treatment of choice for postmenopausal patients with positive estrogen receptor status; has also been found to reduce risk of breast cancer in women at high risk
· Peripheral stem cell therapy for advanced disease
· Primary radiation therapy before or after tumor removal:
§ effective for small tumors in early stages
§ helps make inflammatory breast tumors more surgically manageable
§ also used to prevent or treat local recurrence
· Estrogen, progesterone, androgen, or antiandrogen aminoglutethimide therapy
UNDERSTANDING BREAST CANCER