What is Breast Cancer?
Breast cancer is now the most commonly diagnosed cancer in the world.
When a cell keeps dividing and producing more cells without proper regulation, a mass of unwanted cellular tissue, like a tumorA mass of cells that can be benign or malignant., can form. If the cells in that tumor don’t invade nearby tissues, they are considered benignNot harmful; not cancerous (referring to a cell or mass). or non-cancerous. If the abnormal cells can spread to surrounding tissues and other parts of the body, the tumor is malignantCancerous. or harmful.
In the United States, one out of every eight females will be diagnosed with breast cancer during their lifetime. Breast cancer can develop in the milk-producing glands known as lobes or connective tissue in the chest, but primarily occurs in the milk ducts of the breasts. Everyone has some glandular tissue in their chest, which is why we all carry some level of breast cancer risk.
Breast cancer is not a single disease but a collection of cancers that are categorized by the tumor characteristics. Growth rates depend on many factors including the type of cancer, age at diagnosis, immune response, and the presence of other diseases. These differences in growth rates mean that some breast cancers could take as little as two years to reach a size that’s big enough to feel, while others that grow more slowly could take over ten years to reach that same size.
What Fuels Breast Cancer Growth?
Breast cancer growth is often fueled by hormones in the body, especially estrogenA female sex hormone that is primarily produced by the ovaries. Its primary function is to regulate the menstrual cycle and assist in the production of secondary sex characteristics such as breasts. It may even play a role in the production of cancer cells in the breast tissue. and progesteroneA hormone that stimulates the uterus to prepare for pregnancy, produced mainly by the ovaries. Progesterone may play a role in certain breast cancers.. These cancers are considered hormoneA chemical substance produced in the body that controls and regulates the activity of certain cells or organs. receptor-positive cancers. Approximately 80 percent of all female breast cancers are influenced by estrogen while two-thirds of cases are fueled by progesterone. Even though males have reduced amounts of these hormones, they can develop breast cancer. Although male breast cancer is far less common, 90 percent are hormone receptor-positive.
Some cells produce too much of a protein called human epidermal growth factor 2 (HER2) which can promote cancer growth. This overabundance is found in 20-25% of breast cancer cases. A less common yet more aggressive form of breast cancer, referred to as triple-negative breast cancer, is not fueled by any of these factors.
Research has identified several hormonal, chemical, and genetic factors that are known to influence our breast cancer risk. Some risk factorsAnything that increases or decreases a person’s chance of developing a disease., such as being born female and aging, are beyond our control. However, there are several lifestyle-related risk factors that can be modified to lower breast cancer risk.
How is Breast Cancer Detected?
- Everyone performs the monthly breast self-exam by age 18
- Females start yearly clinical exams by age 19 but no later than age 25
- Females begin yearly mammogramsA low dose x-ray picture of the breast that allows a doctor to view glandular tissue and determine the presence of cancer. by age 40
How is Breast Cancer Diagnosed?
Screening methods are a great way to detect suspicious lumps, but they do not determine whether a mass is benign or malignant. In fact, about 80% of breast lumps are harmless. The only definitive way to diagnose breast cancer is through a biopsyThe removal and examination of tissue from a living body to discover the presence, cause, or extent of a disease., which is the partial or complete removal of the suspicious lesion for analysis by a pathologistA doctor who specializes in examining tissues and cellular changes..
Fine needle biopsy is an effective, non-surgical means that uses either ultrasound or mammography to locate the suspicious lesion, and then remove several small samples for evaluation. Under certain circumstances, a surgical biopsy can remove tissue from a suspected mass for diagnostic testing.
How is Breast Cancer Treated?
Treatment options are evolving on a continuous basis. More so than ever before, breast cancer treatment has become highly personalized, based on the genetic makeup of the individual as well as the tumor. Not all interventions are available to all breast cancer patients. In recent years, there has been a focus on offering treatment before cancer surgery or other primary cancer treatment. This is done to monitor the effectiveness of the treatment and either to avoid surgery or improve surgical outcomes.
Breast cancer treatments fall into two categories:
Localized treatment: only treats the tumor or very specific area, without affecting the rest of the body. Local interventions, like surgery and radiation therapy, may be the sole mode of treatment for early-stage cancers, or a combination of localized and systemic treatments may be used for more advanced cancers.
Systemic treatmentA treatment like chemotherapy or hormonal therapy that affects the whole body or system, as opposed to localized treatment, such as surgery or radiation.: can reach cancer cells anywhere in the body, using drugs which can be given orally or directly into the bloodstream. Tumors are tested for certain biomarkersA distinct biochemical, genetic, or molecular characteristic or substance that is an indicator of a particular biological condition or process. that help the doctor make more informed decisions about the course of treatment. Systemic options include:
• Hormone therapy
• ChemotherapyTreatment with drugs to destroy or slow down the growth of cancer cells. Often referred to as systematic treatment, because it acts throughout the body, as opposed to localized treatments, like surgery or radiation.
• ImmunotherapyTreatments that attempt to use the body’s own defenses to control the cancer. Also known as immunomodulation.
• Targeted Drug Therapy
If cancer is found early, more treatment options are available, and the regimen may be more tolerable. Finding breast cancer in its earlier stages greatly increases survival rates, which emphasizes the need of practicing every available method of early detection.
Sources
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- American Cancer Society. Breast Cancer Facts & Figures 2019-2020. Atlanta: American Cancer Society, Inc. 2019.
- “Natural History and Prognostic Markers.” Holland-Frei Cancer Medicine. 6th edition. 2003.
- Nakashima, K., Uematsu, T., Takahashi, K. et al. Does breast cancer growth rate really depend on tumor subtype? Measurement of tumor doubling time using serial ultrasonography between diagnosis and surgery. Breast Cancer 26, 206–214 (2019).
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