An American woman has about a 1 in 8 chance of developing breast cancer at some point in her life. More than 246,000 new cases of invasive breast cancer will be diagnosed in women this year while another 61,000 women will be diagnosed with carcinoma in situ (CIS), the earliest, non-invasive form of breast cancer. After skin cancers, breast cancer is the most common form of cancer in American women. (While rare, breast cancer can also develop in males. About 2,300 men in the U.S. are diagnosed with the disease each year.) An estimated 40,450 women will die from breast cancer in 2016.
Significant advances in the early detection and effective treatment of breast cancer have dramatically improved the outlook for women diagnosed with the disease. The 5-year relative survival rate—which compares the survival rate of breast cancer patients with the expected survival rate of their peers without cancer—is 100% for women whose disease is detected and treated in its earliest stages, Stage 0 and Stage I. For somewhat more advanced Stage II breast cancer, the 5-year relative survival rate is 93%. That rate declines for Stage III and Stage IV breast cancer, but thanks to early detection, it is increasingly uncommon to diagnose women at those stages. Further, advanced breast disease is the focus of intense research, with clinicians evaluating a number of drug therapies and other interventions that may add to the treatment options for women with Stage III or IV breast cancer. Due to the great strides made in recent years, there are more than 2.8 million breast cancer survivors in the US today.
The oncology specialists of Regional Cancer Care Associates (RCCA) have helped drive the progress made against breast cancer, both through their provision of cutting-edge care to women and by their work as investigators in clinical trials assessing new approaches to enhancing treatment across the spectrum of breast cancer. While you should discuss questions and concerns about breast cancer with your physician or other health care provider, RCCA’s specialists provide the information on this page for general educational purposes.
Breast Cancer Risk Factors and Prevention
Risk factors for breast cancer—and for almost every disease—can be divided into those a person can control, such as her diet, and those she cannot, such as her age or family history. Risk factors that a person can change are called modifiable risk factors, while those she cannot change are termed non-modifiable risk factors.
Non-modifiable risk factors that increase a woman’s chances of developing the disease include a family history of breast cancer and previously having had breast cancer herself. A personal history of having had cancer in one breast increases the chance that a woman will have a new case of breast cancer—not a recurrence of her original disease—elsewhere in that breast or her other breast. Meanwhile, genetic mutations play a role in 5–10% of breast cancer cases. Having dense breast tissue is associated with a 1.2–2-fold increased risk of breast cancer. While most benign breast lesions are not associated with increased risk, or with only slightly increased risk, proliferative lesions with atypical cells—such as atypical ductal hyperplasia and atypical lobular hyperplasia—elevate risk. Breast cancer risk also increases with age. White women are at elevated risk compared to African-American, Asian, Hispanic, and Native-American women, but when breast cancer does develop in African-American women, they are at higher risk of dying of the disease than are white women. The reasons for this disparity are not entirely understood.
Modifiable risk factors for breast cancer include being overweight or obese after menopause, amount of alcohol intake, and level of physical activity. Increased weight after menopause elevates risk, which also rises in step with alcohol consumption. Meanwhile, several studies indicate that physical activity reduces risk. Women who have not had children, or who had their first child after age 30, appear to have a slightly higher risk of breast cancer compared with other women. Breastfeeding for 1.5 years or more seems to lower risk, but this finding is the focus of continued research. Use of oral contraceptives (OCs) may slightly increase risk, but any elevation in risk appears to decrease over time after a woman stops using OCs. Post-menopausal hormone therapy that contains both estrogen and progesterone increases the risk of developing breast cancer. Estrogen-only post-menopausal hormone therapy, which is appropriate only for women who no longer have a uterus due to hysterectomy, does not appear to increase breast cancer risk. The role of diet in affecting breast cancer risk continues to be studied.
Types of Breast Cancer
There are many types of breast cancer, including:
– Ductal carcinoma in situ (DCIS) – This is a very early form of breast cancer in which cancerous cells are found only in the ducts that carry milk to the nipple. The cure rate for DCIS is very high.
– Invasive ductal carcinoma – In this form of breast cancer, cancerous cells that originated in the milk ducts have spread to other parts of the breast. They also have the potential to spread elsewhere in the body. This is the most commonly seen type of breast cancer.
– Invasive lobular carcinoma – The breast contains glands, or lobules, that produce milk. In this form of breast cancer, cancerous cells that formed in those glands have spread to other parts of the breast. They also can spread to other organs. Invasive lobular carcinoma may develop from lobular carcinoma in situ, a condition in which abnormal cells initially are contained with the glands.
– Inflammatory breast cancer – This rare form of breast cancer usually does not involve a lump or tumor but instead causes generalized inflammation of the breast, often making the breast feel warm and look red.
In addition to these four forms of breast cancer, several other, less-common types also occur.
Signs and Symptoms
Because of screening mammography, more and more cases of breast cancer are being detected before there are outward signs of the disease. Nonetheless, in addition to having regular mammograms in accord with the schedule appropriate for your age and medical history, it is important to remain vigilant for potential signs and symptoms of breast cancer and to see your physician or other health care provider promptly if you find something that causes concern. Patients continue to play a key role in the early detection of breast cancer through attention to signs and symptoms that include:
– A new lump or mass. Regardless of whether the mass is painless or painful, soft or hard, has regular edges or smooth edges, have it assessed by your provider.
– Swelling affecting the entire breast or part of the breast, even if you cannot feel a distinct lump.
– Breast or nipple pain.
– Nipple retraction, meaning that the nipple “pulls back” into the breast.
– Skin dimpling or irritation.
– Scaling, thickening, or redness of the nipple or breast skin.
– Nipple discharge other than breast milk.
– A lump or swelling near the breasts, such as in the armpit or by the collarbone.
Diagnosis, Staging, and Classification
When potential breast cancer is found on mammography, during a breast examination performed by a clinician, or by the patient, physicians can draw on a number of approaches to further evaluate the finding. Beyond taking a detailed medical history and performing a physical examination, a physician often will order imaging studies. Depending on how the potential cancer first was identified and the specifics of the patient’s case, mammography, breast ultrasound, magnetic resonance imaging (MRI), or some combination of those modalities may be employed.
Physicians also may want to obtain breast tissue for examination by a pathologist. In this case, options include fine needle aspiration (FNA) biopsy, which makes use of a thin, hollow needle attached to a syringe to take a tissue sample; core needle biopsy, in which a somewhat larger needle is employed; and surgical, or open, biopsy, in which all or part of a lump is removed by a surgeon. In some cases, physicians will perform a needle biopsy of the lymph nodes in addition to obtaining breast tissue.
When cancerous cells are identified, physicians assess the cancer in a number of different ways. For invasive cancers, physicians assign the tumor a grade from 1 to 3. The grade is based on the extent to which the cancerous cells appear similar to normal breast cells and the speed with which they are dividing. The lower the grade, the slower the cells are growing and the less likely they are to spread. Breast cancer also is classified by whether the surface of cancerous cells contains receptors for the hormones estrogen and progesterone, whether the cells contain a protein called HER2/neu, and the genetic make-up of the cells. This information helps physicians identify which therapies are likely to be most effective for the patient.
If there is concern that the cancer may have spread beyond the breast, chest X-rays, bone scans, computed tomography (CT) scans, MRI, ultrasound, and other imaging studies, as well as additional tests, may be ordered to assess other organs.
Once their evaluation is completed, physicians assign breast cancer a stage, which reflects the extent to which the cancer has spread. A widely employed system devised by the American Joint Committee on Cancer (AJCC) considers tumor size and spread, lymph node involvement, and metastasis—or dissemination to other parts of the body—to determine how the cancer is best categorized along a spectrum from Stage 0, signifying DCIS, to Stage IV, representing spread to lymph nodes or organs far from the breast.
The treatment plan for a patient’s breast cancer is based on several factors, including the location and extent of the disease, the hormone-receptor status and genetic composition of the tumor, the patient’s overall health, and her preferences with regard to treatment issues such as type of operation when surgical intervention is indicated.
Those surgical interventions include lumpectomy, a procedure which removes the tumor and surrounding tissue while leaving the rest of the breast intact, and mastectomy, in which the entire breast is removed. Based on factors including genetic predisposition to breast cancer, some women choose to have bilateral mastectomy, or removal of both breasts. Decisions about surgical treatment and other forms of therapy should be made in close consultation with your physician and, as appropriate, with genetic counselors and other healthcare professionals. In conjunction with surgery to excise cancerous breast tissue, surgeons may also remove lymph nodes from the underarm to see if cancer has spread to those components of the body’s lymph system. Women who have a mastectomy often opt to undergo breast reconstruction surgery at the same time or later.
Radiation therapy is also used to treat breast cancer, and often is administered following surgery to kill any cancer cells that may not have been removed surgically. Radiation can be delivered to the affected site of the body by two means—external and internal. With external beam radiation therapy, or EBRT, a machine outside the body directs high energy rays to a precise location in the breast or nearby area. Alternatively, tiny radioactive seeds can be placed in breast tissue adjacent to the cancer. In this approach, called brachytherapy, the seeds emit radiation into a small radius in the immediately surrounding tissues to kill the cancer cells.
Chemotherapy, given via pills or introduction into a vein, also is used to treat breast cancer, with many chemotherapy regimens for the disease involving combinations of two or more agents. Because the growth of some breast cancers is fueled by the female hormone estrogen, physicians sometimes will administer hormonal therapies, such as tamoxifen, to reduce estrogen levels or block the effect of estrogen.
The benefits offered by each treatment have to be weighed against its potential side effects, and it is important for patients to discuss both risks and benefits with their physician in order to make informed decisions about their care.
In the last several years, physicians’ understanding of the genetic, molecular, hormonal, and other processes driving breast cancer has increased exponentially. This knowledge has helped oncologists devise sophisticated treatment strategies tailored to the needs of each patient. Those approaches often combine surgery, radiation, or both with chemotherapy and hormonal therapies selected on the basis of the receptor status and other characteristics of the patient’s cancer.
Even more individualized approaches are likely in the years ahead, as clinical trials evaluate strategies to further increase survival, enhance other outcomes, and reduce the toll that breast cancer continues to take on women.
The oncologists of Regional Cancer Care Associates are always available to see you or consult with your physician if you have been diagnosed with breast cancer. In addition, here are some reliable resources for obtaining further information:
American Cancer Society (ACS) – http://www.cancer.org/cancer/breastcancer/index
Centers for Disease Control and Prevention (CDC) – http://www.cdc.gov/cancer/breast/
National Cancer Institute (NCI) – http://www.cancer.gov/types/breast