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Specializing in Cancer Care
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Tampa Bay Oncology Center |
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Breast cancer occurs when there is a mutation of cells normally present in the breast, resulting in uncontrolled proliferation of these cells that line the milk ducts and lobules (milk producing component). Once the cancerous cells have invaded through the basement membrane of the system that transports milk to the nipple, spread can occur through the bloodstream or lymphatic system. Lymph is the clear component of circulation that drains to the lymph nodes located in the axilla, which is located under the arm. The breast cancer then grows as a mass within the breast, which can be detected by X-rays (mammography), or by examination (palpation).
Breast cancer is the most common malignancy affecting women in the Western hemisphere, resulting in more than 200,000 cases per year. It is the second leading cause of cancer death in American women, behind lung cancer. The risk of getting breast cancer is about 1in 8, and the risk of dying of breast cancer is lower at 1 in 28.
Risk factors can be divided into two categories: those that you can control, and those that you cannot. Factors beyond your control include age, family history (mother, sister, or daughter with breast cancer), personal history of breast cancer, late menopause (after age 50), having no children or having them past the age of 30, and having a genetic mutation for breast cancer. Less than 10% of breast cancer are due to BRCA1 or BRCA2 genes, and testing is available for certain high risk individuals.
Factors that can be controlled include hormone replacement therapy, not breastfeeding, alcohol consumption, being overweight, and lack of exercise. None of these are as important as age and family history, however. All of these factors are based on statistical probabilities, and many individuals without any of these risk factors still get breast cancer.
Screening for breast cancer includes mammograms, clinical breast exams, and breast self-examination. Mammograms can detect tumors while they are too small to be felt. Regular screening examinations can decrease the mortality rate by perhaps 30%. All women should get annual mammograms beginning at age 50, and those with high risk factors should begin even earlier. Between the ages of 20 to 39 every woman should have a clinical breast examination done by a health professional every three years, and every year after age 40. Every woman should do a self-breast examination once a month; perhaps 15% of tumors can be felt but not seen on routine screenings mammograms.
The clinical signs of breast cancer include the following, but unfortunately early breast cancer can present without any of these findings:
-Lump or thickening in the breast -Change in size or shape -Nipple discharge or turning inward -Redness or scaling of the skin or nipple -Ridges or pitting
If there is suspicion of breast cancer, the patient should undergo a diagnostic mammogram (more detailed than the screening version), and perhaps an ultrasound study. If the suspicion remains high, the next step is a biopsy to confirm or deny the diagnosis of cancer. A pathologist will analyze the biopsy specimen and if malignant, will document the grade (how abnormal the specimen looks under the microscope), degree of invasiveness, adequacy of resection (margins), and certain other predictive factors including estrogen and progesterone receptors, and growth factor receptors (HER-2/neu).
Once the diagnosis of malignancy is established, it is necessary to stage the patient in order to define the appropriate treatment regimen. A representative staging system is as follows:
-Stage 0: Cancer cells are identified microscopically in the lining of the glands or ducts, but there is no invasion through the basement membrane. -Stage I: Tumor size is less than 2 cm -Stage II: Tumor is between 2 and 5 cm, or has spread to axillary lymph nodes -Stage III: Tumor greater than 5 cm in size or extensive local spread to lymph nodes -Stage IV: Cancer spread outside the breast to distant sites
Additional tests may be necessary to further define the extent of disease, such as additional X-rays, bone scans, CT scans, and PET (positron emission tomography) scans.
Once all of the diagnostic tests and staging have been completed, attention is turned to selecting the most appropriate treatment. The available options include surgery, radiation therapy, chemotherapy, hormone therapy, and biologic therapy. Some type of surgery is necessary in all instances of breast cancer; the extent of surgery can range from “lumpectomy” all the way to modified radical mastectomy. Breast conservation therapy is frequently employed, and consists of removal of the entire tumor from the breast with attainment of clear margins all around the tumor. Currently, radiation therapy is indicated in all cases of breast conservation based on the results of several clinical trials. Even with more aggressive surgery such as partial mastectomy or segmental mastectomy, radiation therapy is employed to decrease the risk of recurrence. Clinical trials have also shown that the results of breast conservation equal those of surgery, so that breast conservation has become the standard of care in properly selected cases.
More advanced presentations of breast cancer are often treated with more aggressive surgery such as mastectomy, often combined with removal of the contents of the axilla. For those patients undergoing mastectomy, many different types of reconstructive surgery are available and can be discussed with a plastic surgeon.
Chemotherapy has potential preventive benefit in two contexts; to eradicate microscopic cancer cells which may have spread outside of the breast to other parts of the body, and to complement surgery and radiation therapy in preventing a local recurrence in the breast or chest wall after mastectomy. The decision to accept chemotherapy depends upon assessment of the risks (side effects) of treatment versus the potential benefit in helping prevent a recurrence. Many different chemotherapy regimens are available and should be discussed with a medical oncologist. Chemotherapy is also indicated in instances of metastatic or recurrent disease.
Biologic therapy involves an attempt to control or limit cancer progression through manipulations of the immune system, growth factors, or blood supply to the tumor. There is much interest in this concept since it represents a “targeted” approach to cancer therapy. For example, a growth factor receptor by the name of HER-2/neu can be targeted by monoclonal antibodies, thus blocking the signal to stimulate tumor growth.
After treatment, careful follow-up is necessary to monitor for a recurrence which can be salvaged in many cases. The further out from treatment, the less frequent the follow-up visits need to be. Mammography and breast examination continue to be integral parts of follow-up, just as they were in the screening process.
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Breast Cancer : An Overview |