Breast cancer is the most common cancer among women. Breast cancer is a malignant tumor (a collection of cancer cells) arising from the cells of the breast. Although breast cancer predominantly occurs in women, it can also affect men. Breast cancer is rare in men (approximately 2,400 new cases diagnosed per year in the U.S.) but typically has a significantly worse outcome. This is partially related to the often late diagnosis of male breast cancer, when the cancer has already spread. Symptoms are similar to the symptoms in women, with the most common symptom being a lump or change in skin of the breast tissue or nipple discharge. Although it can occur at any age, male breast cancer usually occurs in men over 60 years of age.
Breast cancer does not always produce symptoms; women may have cancers that are so small they do not produce masses that can be felt or other recognizable changes in the breast. When symptoms do occur, a lump or mass in the breast is the most common symptom. Other possible symptoms include:
- nipple discharge or redness,
- changes in the skin such as puckering or dimpling,
- and swelling of part of the breast
- bloody nipple discharge,
- inverted nipple,
- breast pain or sore nipple,
- swollen lymph nodes in the neck or armpit, and
- a change in the size or shape of the breast or nipple.
There are many different types of breast cancer that differ in their capability of spreading (metastasize) to other body tissues. The causes of breast cancer are not yet fully known, although a number of risk factors have been identified. Breast cancer is diagnosed during a physical exam, by self-examination of the breasts, mammography, ultrasound testing, and biopsy. Treatment of breast cancer depends on the type of cancer and its stage (0-IV) and may involve surgery, radiation, or chemotherapy.
Some breast cancers are more common than others, and there are also combinations of cancers. Some of the most common types of cancer are as follows:
- Ductal carcinoma in situ: This type of cancer has not spread and therefore usually has a very high cure rate.
- Invasive ductal carcinoma: This cancer starts in a duct of the breast and grows into the surrounding tissue. It is the most common form of breast cancer. About 80% of invasive breast cancers are invasive ductal carcinoma.
- Invasive lobular carcinoma: This breast cancer starts in the glands of the breast that produce milk. Approximately 10% of invasive breast cancers are invasive lobular carcinoma.
The other breast cancers are much less common and include the following:
- Mucinous carcinoma, formed from mucus-producing cancer cells. Mixed tumors contain a variety of cell types.
- Medullary carcinoma is an infiltrating breast cancer that presents with well-defined boundaries between the cancerous and noncancerous tissue.
- Inflammatory breast cancer: This cancer makes the skin of the breast appear red and feel warm (giving it the appearance of an infection). These changes are due to the blockage of lymph vessels by cancer cells.
- Triple-negative breast cancer: This is a subtype of invasive cancer with cells that lack estrogen and progesterone receptors and have no excess of a specific protein (HER2) on their surface. It tends to appear more often in younger women and African-American women.
- Paget’s disease of the nipple: This cancer starts in the ducts of the breast and spreads to the nipple and the area surrounding the nipple. It usually presents with crusting and redness around the nipple.
- Adenoid cystic carcinoma: These cancers have both glandular and cystic features. They tend not to spread aggressively and have a good prognosis.
- Lobular carcinoma in situ: This is not a cancer but an area of abnormal cell growth that can lead to invasive breast cancer later in life.
The following are other uncommon types of breast cancer:
- Papillary carcinoma
- Phyllodes tumor
- Tubular carcinoma
There are many risk factors that increase the chance of developing breast cancer. We know that normal breast cells become cancerous because of mutations in the DNA, and although some of these are inherited, most DNA changes related to breast cells are acquired during one’s life.
Proto-oncogenes help cells grow. If these cells mutate, they can increase growth of cells without any control. Such mutations are referred to as oncogenes. Such uncontrolled cell growth can lead to cancer.
Some of the breast cancer risk factors can be modified (such as alcohol use) while others cannot be influenced (such as age). It is important to discuss these risks with a health-care provider anytime new therapies are started (for example, postmenopausal hormone therapy).
Several risk factors are inconclusive (such as deodorants), while in other areas, the risk is being even more clearly defined (such as alcohol use).
The following are risk factors for breast cancer:
- Age: The chances of breast cancer increase as one gets older.
- Family history: The risk of breast cancer is higher among women who have relatives with the disease. Having a close relative with the disease (sister, mother, daughter) doubles a woman’s risk.
- Personal history: Having been diagnosed with breast cancer in one breast increases the risk of cancer in the other breast or the chance of an additional cancer in the original breast.
- Women diagnosed with certain benign breast conditions have an increased risk of breast cancer. These include a typical hyperplasia, a condition in which there is abnormal proliferation of breast cells but no cancer has developed.
- Menstruation: Women who started their menstrual cycle at a younger age (before 12) or went through menopause later (after 55) have a slightly increased risk.
- Breast tissue: Women with dense breast tissue (as documented by mammogram) have a higher risk of breast cancer.
- Race: White women have a higher risk of developing breast cancer, but African-American women tend to have more aggressive tumors when they do develop breast cancer.
- Exposure to previous chest radiation or use of diethylstilbestrol increases the risk of breast cancer.
- Having no children or the first child after age 30 increases the risk of breast cancer.
- Breastfeeding for one and a half to two years might slightly lower the risk of breast cancer.
- Being overweight or obese increases the risk of breast cancer both in pre- and postmenopausal women but at different rates.
- Use of oral contraceptives in the last 10 years increases the risk of breast cancer slightly.
- Using combined hormone therapy after menopause increases the risk of breast cancer.
- Alcohol use increases the risk of breast cancer, and this seems to be proportional to the amount of alcohol used. A recent study reviewing the research on alcohol use and breast cancer concluded that all levels of alcohol use are associated with an increased risk for breast cancer. This includes even light drinking.
- Exercise seems to lower the risk of breast cancer.
- Genetic risk factors: The most common causes are mutations in the BRCA1 and BRCA2 genes (breast cancer and ovarian cancer genes). Inheriting a mutated gene from a parent means that one has a significantly higher risk of developing breast cancer.
Research has shown that parabens (a preservative used in deodorants) can build up in breast tissues. However, this study did not show that parabens cause breast cancer or that the parabens (which are found in many other products) were linked to the use of deodorants.
A 2002 study did not show any increased risk for breast cancer in women using an underarm deodorant or antiperspirant. A 2003 study showed an earlier age for breast cancer diagnosis in women who shaved their underarms more frequently and used underarm deodorants.
More research is needed to give us the answer about a relationship between breast cancer and underarm deodorants and blade shaving.
Although breast cancer can be diagnosed by the above signs and symptoms, the use of screening mammography has made it possible to detect many of the cancers early before they cause any symptoms.
The American Cancer Society (ACS) has the following recommendations for breast cancer screenings:
Women should have the opportunity to begin annual screening between 40-44 years of age. Women age 45 and older should have a screening mammogram every year until age 54. Women 55 years of age and older should have biennial screening or have the opportunity to continue screening annually. Women should continue screening mammography as long as their overall health is good and they have a life expectancy of 10 years or longer. Mammograms are a very good screening tool for breast cancer. As in any test, mammograms have limitations and will miss some cancers. An individual’s family history and mammogram and breast exam results should be discussed with a health-care provider.
The ACS does not recommend clinical screening exams in women of any age. Women at high risk (greater than 20% lifetime risk) should get an MRI and a mammogram every year. Women at moderate risk (15%-20%) should talk to their doctor about the benefits and limitations of adding MRI screening to their yearly mammogram.
Staging is the process of determining the extent of the cancer and its spread in the body. Together with the type of cancer, staging is used to determine the appropriate therapy and to predict chances for survival. To determine if the cancer has spread, several different imaging techniques can be used.
- Chest X-ray: It looks for spread of the cancer to the lung.
- Mammograms: More detailed and additional mammograms provide more images of the breast and may locate other abnormalities.
- Computerized Tomography (CT Scan): These specialized X-raysare used to look at different parts of your body to determine if the breast cancer has spread. It could include a CT of the brain, lungs, or any other area of concern.
- Bone Scan: A bone scan determines if the cancer has spread (metastasized) to the bones. Low level radioactive material is injected into the bloodstream, and over a few hours, images are taken to determine if there is uptake in certain bone areas, indicating metastasis.
- Positron emission tomography (PET scan): A radioactive material is injected that is absorbed preferentially by rapidly growing cells (such as cancer cells). The PET scanner then locates these areas in your body.
Patients with breast cancer have many treatment options. Most treatments are adjusted specifically to the type of cancer and the staging group. Treatment options are being adjusted frequently and your health care provider will have the information on the current standard of care available. Treatment options should be discussed with a health care team. The following are the basic treatment modalities used in the treatment of breast cancer.
- Surgery: Most women with breast cancer will require surgery. Broadly, the surgical therapies for breast cancer can be divided into breast-conserving surgery and mastectomy.
- Breast-conserving surgery: This surgery will only remove part of the breast (sometimes referred to as partial mastectomy). The extent of the surgery is determined by the size and location of the tumor. In a lumpectomy, only the breast lump and some surrounding tissue are removed. The surrounding tissues (surgical margins) are inspected for cancer cells. If no cancer cells are found, this is called “negative” or “clear margins.” Frequently, radiation therapy is given after lumpectomies.
- Mastectomy: During a mastectomy (sometimes also referred to as a simple mastectomy), all the breast tissue is removed. If immediate reconstruction is considered, a skin-sparing mastectomy is sometimes performed. In this surgery, all the breast tissue is removed as well, but the overlying skin is preserved.
- Radical mastectomy: During this surgery, the surgeon removes the auxiliary lymph nodes as well as the chest wall muscle in addition to the breast. This procedure is done much less frequently than in the past, as in most cases, a modified radical mastectomy is as effective.
- Modified radical mastectomy: This surgery removes the auxiliary lymph nodes in addition to the breast tissue. Depending on the stage of the cancer, a health care team might give someone a choice between a lumpectomy and a mastectomy. Lumpectomy allows sparing of the breast but usually requires radiation therapy afterward. If lumpectomy is indicated, long-term follow-up shows no advantage of a mastectomy over the lumpectomy.
- Preventive surgery: For a small group of patients who have a very high risk of breast cancer, surgery to remove the breasts may be an option. Although this reduces the risk significantly, a small chance of developing cancer remains.
Double mastectomy is a surgical option to prevent breast cancer. This prophylactic (preventive) surgery can decrease the risk of breast cancer by about 90% for women at moderate to high risk for breast cancer. Such an approach should be carefully discussed with a health care team. The discussion about whether to undergo any preventive surgery should include genetic testing for BRCA1 or BRCA2 gene mutations, full review of risk factors, family history of cancer and specifically breast cancer, and other preventive options such as medications.
- Radiation therapy: Radiation therapy destroys cancer cells with high energy rays. There are two ways to administer radiation therapy.
1. External beam radiation: This is the usual way radiation therapy is given for breast cancer. A beam of radiation is focused onto the affected area by an external machine. The extent of the treatment is determined by a health care team and is based on the surgical procedure performed and whether lymph nodes were affected or not. The local area will usually be marked after the radiation team has determined the exact location for the treatments. Usually, the treatment is given five days a week for five to six weeks.
2. Brachytherapy: This form of delivering radiation uses radioactive seeds or pellets. Instead of a beam from the outside delivering the radiation, these seeds are implanted into the breast next to the cancer.
- Chemotherapy: Chemotherapy is treatment of cancers with medications that travel through the bloodstream to the cancer cells. These medications are given either by intravenous injection or by mouth. Chemotherapy can have different indications and may be performed in different settings as follows:
- Adjuvant chemotherapy: If surgery has removed all the visible cancer, there is still the possibility that cancer cells have broken off or are left behind. If chemotherapy is given to assure that these small amounts of cells are killed as well, it is called adjunct chemotherapy. Chemotherapy is not given in all cases, since some women have a very low risk of recurrence even without chemotherapy, depending upon the tumor type and characteristics.
- Neoadjuvant chemotherapy: If chemotherapy is given before surgery, it is referred to as neoadjuvant chemotherapy. Although there seems to be no advantage to long-term survival whether the therapy is given before or after surgery, there are advantages to see if the cancer responds to the therapy and by shrinking the cancer before surgical removal.
- Chemotherapy for advanced cancer: If the cancer has metastasized to distant sites in the body, chemotherapy can be used for treatment. With cases of metastatic breast cancer, the health-care team will need to determine the most appropriate length of treatment.
There are many different chemotherapeutic agents that are either given alone or in combination. Usually, these drugs are given in cycles with certain treatment intervals followed by a rest period. The cycle length and rest intervals differ from drug to drug.
- Hormone therapy: This therapy is often used to help reduce the risk of cancer reoccurrence after surgery, but it can also be used as adjunct treatment. Estrogen (a hormone produced by the ovaries) promotes the growth of a few breast cancers, specifically those containing receptors for estrogen (ER positive) or progesterone (PR positive). The following drugs that prevent estrogen from binding to estrogen receptors on breast cells, eliminates the estrogen receptor, or stop estrogen production in postmenopausal women. are used in hormone therapy.
- Targeted therapy: As we are learning more about gene changes and their involvement in causing cancer, drugs are being developed that specifically target the cancer cells. They tend to have fewer side effects than chemotherapy (as they target only the cancer cells) but usually are still used in adjunct with chemotherapy.
- Alternative treatments: Whenever a disease has the potential for much harm and death, physicians search for alternative treatments. As a patient or the loved one of a patient, there may be an inclination to try everything and leave no option unexplored. The danger in this approach is usually found in the fact that the patient might not avail themselves of existing, proven therapies. One should discuss any interest in alternative treatments with a health care team and together explore the different options.
There is no guaranteed way to prevent breast cancer. Reviewing the risk factors and modifying the ones that can be altered (increase exercise, keep a good body weight, etc.) can help in decreasing the risk.
Following the American Cancer Society’s guidelines for early detection can help early detection and treatment.
Chemoprevention is the use of medications to reduce the risk of cancer. The two currently approved drugs for chemoprevention of breast cancer are tamoxifen (a medication that blocks estrogen effects on the breast tissue) and raloxifene (Evista), which also blocks the effect of estrogen on breast tissues. Their side effects and whether these medications are right for an individual need to be discussed with a health care provider.
Aromatase inhibitors are medications that block the production of small amounts of estrogen usually produced in postmenopausal women. They are being used to prevent reoccurrence of breast cancer but are not approved at this time for breast cancer chemoprevention.
For a small group of patients who have a very high risk of breast cancer, surgery to remove the breasts may be an option. Although this reduces the risk significantly, a small chance of developing cancer remains.
Recent discoveries are listed below:
Advances in prevention and early detection
- Newly discovered rare genetic mutations linked to higher breast cancer risk. A global study has identified rare genetic changes that increase the risk of developing breast cancer. People who carry these rare mutations have been found to have a similar risk of developing breast cancer as those who carry the more common BRCA1 and BRCA2 gene mutations. Learning about rare genetic mutations is helpful for researchers so they can continue to investigate how best to reduce risk and treat people at high genetic risk.
- Osteoporosis drug may help prevent breast cancer in people at high risk. Cancer researchers at Walter and Eliza Hall Institute have found that denosumab (Xgeva), a drug most commonly used in osteoporosis treatment, is effective in preventing breast cancer in women who carry a BRCA1 gene mutation. This breakthrough may mean women with a BRCA1 gene mutation will have a less invasive option for reducing their risk of breast cancer in the future.
- Longer-term use of aromatase inhibitors may help stop some breast cancers returning. Researchers in the US have found that taking the aromatase inhibitor letrozole for 10 years instead of five can further reduce the risk of breast cancer coming back for some women. Letrozole may also be effective in preventing new cancers from developing in the opposite breast.
- Blood test may help predict when a cancer is returning. New research shows that a blood test might accurately predict the return of cancer in people who have been previously treated for early stage cancers. The blood test, also known as ‘liquid biopsy’, looks for cancer DNA in the bloodstream from cancer cells that have resisted treatment.
Advances in treatment
- New targeted therapies for a common type of metastatic breast cancer
The PALOMA2 clinical trial found the new breast cancer drug palbociclib (Ibrance) to be an effective new first line treatment for hormone receptor positive, HER2-negative breast cancer when used in combination with the hormone therapy drug letrozole. The addition of palbociclib almost doubled progression free survival from 9 to 18 months.
A subsequent trial in later line therapies has found that palbociclib used in combination with fulvestrant (Faslodex), can slow cancer growth in around two-thirds of women with hormone receptor positive, HER2-negative metastatic breast cancer. Another clinical trial has shown that ribociclib, when taken with the aromatase inhibitor letrozole, significantly improves survival of women being treated for hormone receptor positive metastatic breast cancer.
- New targeted treatments for triple negative breast cancer. Three recent clinical trials have shown promising results in the treatment of triple negative breast cancer by using the immune system to target the growth of cancer cells.
- Tykerb and Herceptin in the treatment of HER2-positive early breast cancer. New research shows that giving a combination of the targeted drugs trastuzumab (Herceptin) and lapatinib (Tykerb) before surgery is effective in rapidly shrinking some HER2-positive breast cancers.
Improvements in quality of life and management of side effects
- Scalp cooling systems can help reduce hair loss during chemotherapy. Research has shown that a scalp cooling system can reduce severe hair loss by 50 per cent in some women who are going through chemotherapy.
- New online interventions can help women manage fear of recurrence. An Australian study testing the effectiveness of one-on-one therapy sessions using new psychological techniques has found a 22 per cent reduction in the fear of breast cancer returning.
- Research shows personalized exercise programs can help with treatment side effects in early breast cancer. An Edith Cowen University study has shown that personalized exercise programs can help reduce treatment side effects in early breast cancer. The research demonstrates that moderate, supervised exercise can increase energy levels, help with nausea and muscle loss, and may help some people to recover faster.
Excerpts from Breast Cancer Network Australia (BCNA) and American Cancer Society (ACS)