Breast cancer occurs when malignant tumors develop in the breast, often in the lobules (the milk-producing glands) or in the ducts (the passages that drain milk from the lobules to the nipple). As cancer cells reproduce, they can invade the lymph nodes and blood vessels near the original tumor and spread — or metastasize — to other parts of the body, damaging tissue and other organs.
Breast cancer occurs almost entirely in women, although men can get it too.
About 1 in 8 women in the US (12%) will develop invasive breast cancer during their lifetime. In 2014, more than 232,000 new cases of breast cancer will be diagnosed in women.
Death rates from breast cancer have been declining since 1989, with larger decreases in women younger than 50. The drop is believed to be the result of earlier detection through screening and increased awareness as well as improved treatment.
Top 5 Risk Factors
- Being a woman Women are much more likely than men to develop breast cancer.
- Age 2 out of 3 invasive breast cancers are found in women 55 or older.
- Family history Women with close relatives who’ve been diagnosed with breast cancer — a sister, mother or daughter — double their risk of developing the disease.
- Genetics About 5% to 10% of breast cancers are thought to be hereditary, caused by abnormal genes passed from parent to child — most commonly the BRCA1 and BRCA2 genes.
- Personal History Women diagnosed with breast cancer are 3 to 4 times more likely to develop a new cancer in the other breast or a different part of the same breast. (For more risk factors, see BreastCancer.org.)
Breast Cancer Detection
Breast cancer discovered in an early stage — where it is still localized and hasn’t spread to other parts of the breast tissue, lymph nodes or body — is much easier to treat, and survival rates for women are much higher.
There are several ways to discover the presence of breast cancer:
Self exam Women of all ages are encouraged to examine their breasts for lumps or other abnormalities at least once a month. 40% of diagnosed breast cancers are detected by women who feel a lump in their breast, say experts at the Johns Hopkins Medical Center.
Clinical breast exam During an office exam, a healthcare professional can check for lumps or other physical changes in the breast that may need to be investigated.
Mammogram A mammogram is an x-ray that allows a specialist to examine the breast tissue for any suspicious areas. Mammograms can often show a breast lump before it can be felt. Lumps can be caused by cancer, fatty cells or benign conditions like cysts. Further tests — such as an ultrasound, MRI or biopsy — are needed to find out if abnormal cells are present. (The US Preventive Services Task Force, the American Cancer Society and other health organizations have different screening recommendations for mammograms. Consult with your doctor about when and how often you should be screened.)
Breast Cancer Treatment
If a woman is found to have breast cancer, several treatment options are available. Her medical team will consider: the type and stage of the cancer, and whether or not it has spread; her age, health and menstrual or menopausal stage; and whether or not this is her first cancer treatment. Some women may take a “watchful waiting” approach if the lesions are not palpable, and a recent study, reported here, finds that in many cases that option can be safe as long as careful followup is done. Others will explore one or more of the following options:
Many women with breast cancer have some type of surgery, combined with radiation or chemotherapy. Common surgeries include:
- Lumpectomy: The least invasive breast cancer surgery — removes the tumor and a small portion of the surrounding tissue.
- Masectomy: The 3 kinds of mastectomy are: Partial, which removes a larger portion of the breast — a whole segment or quadrant of tissue — in order to eliminate the cancer; Simple — also known as a total masectomy — which removes the breast, nipple, areola and sentinel lymph nodes (the first lymph nodes to which cancer cells are most likely to spread from a primary tumor); and Modified radical, which removes the breast, nipple, areola and axillary lymph nodes (lymph nodes in the underarm area).
- In some cases, doctors will also perform a sentinel node biopsy or axillary node dissection to remove and examine lymph nodes and determine whether the cancer has spread and to what extent.
uses a combination of drugs to either destroy or slow down the growth of cancer cells. The drugs are given orally or intravenously (through a vein) and travel in the bloodstream throughout the entire body.
uses high-energy rays to destroy or damage cancer cells. Unlike chemotherapy, it affects cells only in the part of the body that is treated with the radiation. Radiation therapy may be used to destroy any remaining mutated cells that remain in the breast or armpit area after surgery.
4. Hormone therapy drugs
such as tamoxifen (brand names Nolvadex or Soltamox), help to destroy cancer cells by cutting off their supply of hormones, such as estrogen or progesterone. Some breast cancer cells have receptors that feed on these hormones, stimulating their growth. Hormone blockers (tamoxifen) and aromatase inhibitors (anastrozole, exemestane, letrozole) — used in postmenopausal women — are taken orally, often to reduce the risk of breast cancer in high-risk women or to prevent the recurrence of cancer after surgery. Hormone therapy is given for at least 5 years and can reduce the recurrence of certain (hormone-dependent) breast cancers by 50%.
5. Targeted therapies
These are newer treatments that attack specific breast cancer cells without harming normal cells. The targeted methods are often used in combination with traditional chemotherapy — although they generally have fewer side effects than standard chemotherapy drugs.
Trastuzumab (brand name Herceptin) and lapatinib (brand name Tykerb) are two common drugs used in such treatments. They target the presence of HER2-positive tumors in cells and ultimately shrink them. Trastuzumab is given intravenously. Lapatinib is given orally. Both drugs may be used in conjunction with chemotherapy. (Breastcancer.org has more information about the latest status of targeted therapy drugs.)
Before beginning any course of treatment, tell your doctor about any prescription or non-prescription drugs you are taking — as well as any vitamins and herbal or dietary supplements. Drugs and supplements may interfere with the effectiveness of the breast cancer treatment and/or make side effects worse.
For More Information
Two Boston Docs Want to Study Aspirin as a Treatment for Breast Cancer (Bostonmagazine.com)
Breast Cancer Drug Has a Surprising New Application, Study Finds (Time magazine)
Gene Marker May Predict Breast Cancer Response to Tamoxifen (Medical XPress)
Study Identifies Genes Linked to Breast Cancer in East Asian Women (Medical XPress)
Removing Healthy Breast of Little Benefit to Breast Cancer Patients: Study (Health Day)
Breast Cancer: One-Shot Therapy Gets NHS Nod (BBC News)