Breast cancer is the most common type of cancer among women in the United States, affecting one in every eight women at some point in their lives (a total of two million U.S. women currently). It accounts for one out of every three cancer diagnoses in women. About 200,000 women—and 1,500 men—are diagnosed with breast cancer in the U.S. each year. It was the leading cause of cancer deaths for women from the 1950s through the mid-1980s, until rising rates of lung cancer deaths among women overshadowed it, and it is still the leading cause of cancer deaths for women aged 40 to 49.
The number of breast cancer diagnoses in the United States has increased in recent years because mammography has allowed earlier detection, but at the same time the number of deaths due to breast cancer has been declining. Between 1989 and 1995 death rates declined by 1.4 percent per year, and they declined by 3.2 percent per year after that.
If detected early, breast cancer is one of the most treatable cancers. When breast cancer is confined to the breast, the five-year survival rate is 97 percent. If cancer has invaded the area around the breast, however, the rate drops to 78 percent, and with distant metastases to only 23 percent.
Caucasian, Hawaiian, and African-American women have the highest rates of invasive breast cancer in the United States, while Korean, American Indian, and Vietnamese women have the lowest rates. However, African-Americans experience the highest death rate from breast cancer and are more likely to be diagnosed with a later stage of breast cancer. The precise reasons for this difference are not clear, but may be related to differences in the aggressiveness of the tumors themselves, differences in socioeconomic resources or access to treatment, or the presence of additional illnesses.
Caucasian women, on average, seek medical care for tumors at an earlier stage of disease than African-American women, but this may be in part because black women develop breast cancer at a slightly younger age, when they are less accustomed to checking for it. In general, younger women tend to have more aggressive breast cancers, which may explain why survival rates are lower. Currently some researchers are investigating why breast cancer strikes a greater proportion of black women at a younger age, and whether these differences in the racial pattern of breast cancer have implications for screening recommendations.
The most significant risk factor for breast cancer is being female. The second is getting older; 77 percent of breast cancer cases occur in women over 50. Having a first-degree relative (a mother, sister or daughter) with breast cancer roughly doubles one’s risk for breast cancer. Other potential risk factors include smoking, having more than one alcoholic drink per day, eating a high-fat diet, having a pre-cancerous condition on a previous biopsy, having one’s first period before the age of 12 or menopause after the age of 55, receiving radiation to the chest as a child (particularly for treatment of Hodgkin’s Disease), never having children or having one’s first child after age 30, and gaining significant weight as an adult.
A small number (about 5 percent) of very aggressive breast cancers are caused by genetic mutations (such as defects in the BRCA1 or BRCA2 genes affecting the Ashkenazi Jewish population). Women with these mutations generally have multiple relatives who have had breast and ovarian cancers, and they can increase their life expectancy if they use prophylactic treatments before cancer has the chance to develop.
The effect of hormone replacement therapy (HRT) on the risk of breast cancer was evaluated in the large, prospective Women’s Health Initiative study, remembered most prominently for reversing the practice of routine hormone use in the United States almost overnight. The Journal of the American Medical Association reported the initial results in 2002. The subset of women who had used combined estrogen and progesterone HRT before entering the study did have a small increase in the risk of breast cancer—38 cancers per 100,000 women as opposed to 30—after four years of hormone use, but there was no increase in breast cancer deaths. As a result of this study, most practitioners have suggested that women use HRT only when their menopausal symptoms are so severe as to interfere substantially with functioning or quality of life, and that they use them for the shortest period possible.
Some natural menopausal remedies such as soy and the herb black cohosh have been suggested as alternatives. These compounds are called phytoestrogens, or plant estrogens. There is conflicting evidence, however, about their safety, with some studies showing a protective effect against breast cell changes and some showing a promotion of cancer-like changes.
The publication of the Women’s Health Initiative results regarding HRT caused confusion for many women about the risk of another type of hormone therapy, namely oral contraceptives. The hormone doses in oral contraceptive (OC) pills are far lower than the doses used in HRT. Multiple studies over several decades have investigated whether their use has an effect on breast cancer risk, and in 1992 the Collaborative Group on Hormonal Factors in Breast Cancer was established to collect the worldwide data in a huge database and re-analyze it. Over 50,000 women with breast cancer and 100,000 without the disease were included, and the results were discussed in a meeting held in March 1995. This extensive re-analysis clearly demonstrated that the characteristics of contraceptive use, including type, dose and duration of use, do not increase the lifetime risk of breast cancer, even if OCs are used at a very young age, before the first childbirth or by women with a family history of breast cancer. During the time period that women are using OCs and for 10 years after they stop, there is a slight increase in the number of new diagnoses of breast cancer that is confined to the breast, but there is a decrease in the number of tumors that spread beyond the breast; additionally, because young women have such a low baseline incidence of breast cancer, the absolute number of cases affected is still very small. By ten years after OCs are stopped the number of breast cancer diagnoses is exactly the same as in women who have never used OCs. These findings may reflect an increased monitoring of OC users (for instance, the discovery of tumors because they are receiving exams when they visit the doctor for their prescriptions), or may suggest that OCs stimulate growth of underlying but previously nonevident breast cancer, thus enabling early diagnosis.
At the same time, OCs reduce by up to 80 percent the risk of ovarian cancer, a deadly cancer that is difficult to detect until late stages, lower by 40 to 50 percent the risk of endometrial cancer and nearly eliminate painful ovarian cysts. Long-term OC use also confers protection against some forms of benign breast disease and colorectal cancer, decreases ectopic pregnancy and hospitalizations for pelvic inflammatory disease, helps preserve bone mineral density, and may help prevent rheumatoid arthritis. There are some risks to OC use, most prominently a potential for blood clots, especially in women over 35 who smoke.
Several states have now enacted legislation requiring that women considering abortion be given governmentissued brochures warning that the procedure may increase their subsequent risk of developing breast cancer, despite scientific findings to the contrary. In February 2003, the National Cancer Institute convened a workshop to examine this issue and concluded that having an abortion or miscarriage does not increase a woman’s risk of developing breast cancer. A summary of the institute’s findings, entitled Summary Report: Early Reproductive Events and Breast Cancer Workshop, can be found at the National Cancer Institute website.
The key to surviving breast cancer is early detection and treatment. According to the American Cancer Society, when breast cancer is confined to the breast, the fiveyear survival rate is close to 100 percent. The three key components of early detection are the breast self-exam (BSE), clinical breast exams and mammography.
The breast self-exam involves learning the typical look and feel of one’s own breasts, so that any changes can be readily recognized. By age 20 all women should perform monthly BSEs a few days after the last day of their menstrual cycles. Women who no longer menstruate should do a BSE on the same day each month. At your next health care appointment, ask your health care provider to show you the steps for BSE. Step-by-step instructions are also available from The Susan G. Komen Breast Cancer Foundation.
Many women have a bumpy texture or lumpiness to their breasts that is referred to as fibrocystic breast changes. Often accompanied by tenderness or pain at certain times of the month, these lumps generally move easily and are a normal part of the menstrual cycle. Women are most likely to notice them before the onset of menses and when they take hormones after menopause. Fibrocystic changes do not increase the chances of breast cancer. By contrast, breast changes that should be checked are those that do not change with the menstrual cycle. Any persistent lump or thickening, especially one that is hard or does not move easily, should be examined by your health care provider. The following findings should be checked immediately with a doctor: a lump, hard knot or thickening; unusual swelling, warmth, redness or darkening; change in breast size or shape; dimpling or puckering of the skin; an itchy or scaly sore or rash on the nipple; pulling in of the nipple or other parts of the breast; nipple discharge that starts suddenly; or pain in one spot that does not vary with the menstrual cycle. No matter what the problem, if you feel that something is wrong, ask for a biopsy or get a second opinion. No one knows your breasts better than you.
The clinical breast exam is performed by a health care provider who carefully checks the breasts and underarms for any lumps or changes. Women should have a clinical breast exam at least every three years between the ages of 20 and 39 and yearly after age 40. Many women schedule it at the same time as the pap smear that checks for cervical cancer.
Screening mammography is a low-dose x-ray examination of the breast that can detect breast cancer in the very earliest stages, before a lump can be felt. Research suggests that this very early detection greatly improves women’s chances for successful treatment. The National Cancer Institute recommends that all women begin receiving mammograms every one to two years at age 40, and yearly starting at age 50. In addition, women younger than 40 who are at high risk of breast cancer (i.e., who have an extensive family history of breast cancer or test positive for genetic mutations) should ask their physicians about beginning annual mammograms earlier than age 40, even as early as age 25 in some cases.
Mammograms detect about 85 percent of breast cancers and can find them when they are a full centimeter smaller than can be appreciated by regular breast self exams (and 2.5 cm smaller than the average lump found accidentally). Clinical studies in the U.S., Sweden and the Netherlands have suggested that deaths from breast cancer could be cut by between 36 and 44 percent if mammograms were performed annually on all women. Despite the value of mammograms, however, 33 percent of women over 40—and half of women over 40 who live below the poverty line—have not had a mammogram in the previous 2 years.
Mammography is a relatively low-cost procedure. The average cost for screening mammography in the U.S. is about $100. To facilitate access, in January of 1998 Congress expanded coverage for mammograms for Medicare beneficiaries aged 40 and older. Low-income women without health insurance may also qualify for the National Breast and Cervical Cancer Early Detection Program, sponsored by the Centers for Disease Control (CDC). Additionally, the American Cancer Society (ACS) maintains a list of facilities that offer free or reduced cost mammograms.
Breast cancer is classified by how the cancer cells look under the microscope as well as by the cancer stage (the overall level of disease development in the body). By looking under a microscope, a pathologist determines the type and grade of cancer cells and how quickly the cancer cells are growing. All of these factors affect prognosis and help to guide treatment recommendations.
The two most common types of breast cancer are ductal (75 to 80 percent of cases) and lobular (10 to 15 percent). Ductal cancers originate from cells in the wall of milk-collecting tubes, and lobular cancers originate from the milkproducing cells themselves. Each type can be either in situ (confined to the milk duct) or invasive (expanding into the rest of the breast).
Treatment for breast cancer is determined by a number of factors including the type, stage and aggressiveness of the cancer, the patient’s age and whether the patient is pre- or post-menopausal. The first step involves local therapy at the site of the tumor. Surgery is used to remove the cancer and radiation is used to kill any cells that remain and reduce the risk of local recurrence.
There are basically two types of surgery for breast cancer: breast-conserving surgery (lumpectomy) and mastectomy. In a mastectomy, the entire breast is removed, whereas in breast-conserving surgery, only the tumor and some surrounding tissue are removed. The other major difference between the two procedures is that women almost always have radiation therapy after lumpectomy, but not usually after mastectomy.
Metastasis occurs when breast cancer cells break away from the primary tumor and spread into other organs of the body through the bloodstream. Breast cancer most often spreads to the lymph nodes, lungs, bones, liver or brain. In addition to local treatments such as surgery and radiation, chemotherapy and hormone therapy are often used to target cancer cells that may have spread out of the breast to other parts of the body so they do not colonize into secondary cancer sites in these organs.
Chemotherapy can also be given prior to surgery to reduce the size of the tumors in the breast and lymph nodes and improve the surgical outcome. Also, for women who already have metastatic cancer, chemotherapy is used to decrease the load of cancer cells in the body, with the goal of reducing cancer-related symptoms and prolonging survival.
Hormone therapies such as tamoxifen have been used for more than 20 years to treat breast cancers that are hormone-receptor positive (require the attachment of estrogen for their growth). Tamoxifen and related drugs slow or halt cancer growth by keeping the estrogen from attaching to the cancer cells. They are frequently used for treating post menopausal cancers, and also offered prophylactically to women at high risk of developing cancer because of extensive family history or genetic mutations.
Because of its prevalence, breast cancer will touch the lives of all of us in some way. With the latest combinations of technologies and therapies, survival rates continue to improve. However, early intervention, education and awareness are the mainstays of the fight. For this reason, high-profile personalities such as First Lady Laura Bush, Senator Hillary Clinton and former New York Mayor Rudy Giuliani, as well as celebrities like Halle Berry, Bill Cosby, Cindy Crawford, Kelsey Grammar, Oprah Winfrey and Miss USA Shandi Finnessey, continue to lend their time and support to raise awareness.
by Gillian Friedman, MD
National Cancer Institute cancer.gov
American Cancer Society cancer.org
The Susan G. Komen Breast Cancer Foundation Komen.org
Free BSE card 800 I’M AWARE
National Breast and Cervical Cancer Early Detection Program cdc.gov/cancer/nbccedp/about.htm
Medicare coverage of mammograms—Medicare Hotline 800.638.6833.