Breast cancer is the most commonly diagnosed cancer and the second most common cause of cancer death in women in the United States. About 230,000 women get diagnosed with breast cancer in the U.S. alone and 40,000 women die every year from this condition. Great progress has been made over the past several years in the management of this problem and the survival rate from this once-dreaded cancer has improved significantly, with cure rates of 80 to 90 percent being achieved with early-stage breast cancers.
Breast cancer is most commonly detected by screening mammography, which is usually done in women between 40 and 74 years of age. However, there are many women who detect breast lumps on self-examination and subsequently bring it to medical attention. Once the diagnosis is made, further radiological investigations are obtained. They typically include a diagnostic mammogram, ultrasound scan and MRI scan of the breasts. The next step would be to perform a biopsy of the abnormal area to obtain a pathological confirmation of the underlying condition.
The management of early breast cancer is aimed at both local, regional and systemic control. Surgery and radiation therapy are local treatment options while chemotherapy, hormonal inhibition and other biological therapies reduce risk of systemic recurrence.
Surgical treatment involves either removal of the lump (lympectomy) or removal of the entire breast (mastectomy). In both procedures, it is common practice to remove some lymph nodes from the axilla by a procedure called sentinel node dissection. Depending on the extent of the involvement of the lymph nodes, a complete axillary lymph node dissection might be indicated. In women who undergo mastectomy, early or delayed breast reconstruction is commonly performed.
Radiation therapy is administered following surgery and chemotherapy (if indicated) to reduce the risk of local recurrence. Evolving technologies in radiation delivery have resulted in an improvement of cosmetic outcomes and also in a reduction of normal tissue toxicity.
Chemotherapy continues to be a major strategy in reducing the risk of distant recurrence. Chemotherapy is administered before surgery (neoadjuvant therapy) or following surgery (adjuvant therapy). The primary goal of neoadjuvant therapy is to shrink the tumor and achieve breast conservation. There are several drugs that have been in use for many years which continue to be the cornerstone of the management of breast cancer. Many clinical trials are underway to achieve better outcomes.
About 25 percent of women with breast cancer show an overexpression of a protein called Her-2-Neu on the cell surface. The presence of the amplified Her-2-Neu receptor is considered to be a poor prognostic feature. In women who are Her-2-Neu positive, it is common practice to administer drugs specifically targeting these receptors.
Until recently, only one drug, trastuzumab, was available for use in the adjuvant setting for Her-2-positive women. In the last 12 months, another drug, pertuzumab, has been approved by the FDA to be used along with trastuzumab in the neoadjuvant setting. A combination of these two drugs, along with chemotherapy in the neoadjuvant setting, was shown to achieve a complete response rate of about 40 percent.
About two-thirds of women diagnosed with breast cancer express proteins on the surface of the cancer cells, called estrogen and progesterone receptors. These proteins are stimulated by circulating female hormones which lead to the proliferation of cancer cells.
About 95 percent of the estrogen production in premenopausal women is from the ovaries. About 5 percent of the female hormones is produced by the adrenal glands, liver and subcutaneous fat. In the premenopausal women, the main aim is to use drugs (tamoxifen) to block the effects of the circulating estrogen on the breast cancer cells. In postmenopausal women, the main aim of drugs (anastrozole, letrozole) is to suppress estrogen secretion from the adrenal glands.
Management of metastatic breast cancer is in a state of rapid transformation, with several new drugs being approved in the past 12 months. The median life expectancy of women with metastatic breast cancer is approaching three years, which is a significant achievement. Several chemotherapy drugs, hormonal treatments and biological agents have been proven to be a great value in the management of metastatic breast cancer.
In addition to the medical therapies mentioned above, ancillary support from other specialists such as genetic counselors, social workers, nutritionists, breast cancer navigators and survivorship counselors have significantly improved the quality of care delivered to breast cancer patients all over the country.