Breast cancer is a type of cancer that develops in the tissues of the breast.
- Most cases of breast cancer are seen among women who are about 50 to 69 years old and have attained menopause.
- However, in case of the presence of predisposing factors, cancer may start sooner, such as 40 years.
The risk factors for developing breast cancer are of two types, nonmodifiable and modifiable factors.
11 nonmodifiable risk factors for breast cancer
- Sex: Breast cancer may affect both men and women. However, according to the American Cancer Society, women are 100 times more likely to acquire breast cancer than men.
- Genetic mutations: Many genes associated with breast cancer have been found. The breast cancer genes are BRCA1 and BRCA2. Changes in these genes increase the chance of developing breast and other cancers, such as ovarian cancer. These alterations can result in an 80 percent lifetime risk of getting breast cancer. Alterations in other genes, such as p53, PTEN, and CHEK2, increase the risk of breast cancer.
- Dense breast tissue: Women with dense breast tissue have less fat in their breasts and more fibrous or glandular tissue. Having high-density breast tissue than breast fat increases the risk of acquiring breast cancer.
- Early menstruation and late menopause: It is well established that there is a significant association between breast cancer and female hormones estrogen. Attaining early menstruation (before 12 years) or late menopause (after 55 years) cause prolonged exposure to estrogen hormone in women. This increases the risk of developing breast cancer.
- Personal history of breast conditions or cancer: There is an elevated risk of breast cancer following a breast biopsy, which revealed lobular carcinoma in situ (LCIS) or atypical hyperplasia of the breast. A previous history of breast cancer and treatment may cause a relapse of cancer after several years.
- Family history: The risk of breast cancer increases if any other woman in the family, such as a mother, sister, or daughter, is diagnosed with breast cancer.
- Late pregnancy: Women who have their first child beyond the age of 35 years may be at a slightly greater risk of breast cancer.
- Nulliparity: Breast cancer is more common in women who have never been pregnant than in women who have had one or more pregnancies.
- Postmenopausal hormonal therapy: Women who are on hormone replacement therapy with both estrogen and progesterone after attaining menopause have an increased risk of breast cancer. When women quit taking these drugs, their risk reduces.
- Prolonged use of oral contraceptives: Women who use oral contraceptives (birth control pills) have a slightly increased chance of developing breast cancer. When the pills are withdrawn, the risk reduces to baseline in about 10 years.
- Radiation exposure: Women who received chest radiation treatments during childhood or as young adults, their chances of developing breast cancer are increased.
4 modifiable risk factors for breast cancer
- Overweight: Obesity or being overweight raises the risk of breast cancer. More body fat means more estrogen, and estrogen promotes tumor development. Maintain a healthy weight by being active and eating a well-balanced diet.
- Alcohol consumption: Drinking alcohol raises the chance of developing breast cancer. The danger rises with the increase in the intake of total alcohol amount. The process through which alcohol is digested in a woman’s body may raise estrogen levels in the bloodstream, increasing the risk of breast cancer.
- Being physically inactive: Regular physical exercise lowers the incidence of breast cancer, especially in menopausal women.
- Smoking: Tobacco use increases the risk of at least 15 malignancies, including breast cancer. Women who smoke are more likely to acquire breast cancer than nonsmokers. Long-term secondhand smoking exposure may also increase the risk.
What is breast cancer?
Breast cancer is a type of cancer that develops in the tissues of the breast. It is the most diagnosed cancer in women globally, accounting for one in every eight cancer cases. It is a common malignancy in both sexes and the main cause of cancer deaths in women. Though it affects both men and women, male breast cancer is rare.
There is a good probability of recovery if it is diagnosed in the early stages. So, all women should check their breasts regularly for any abnormal breast lumps and nipple discharge. Seek immediate medical attention if any abnormalities are noted. Following a regimen of regular screening for breast cancers will help detect minor changes in the breast tissue prompting early treatment.
3 types of breast cancers
- Ductal carcinoma: Ductal carcinoma is the most common type of breast cancer. Ductal carcinoma is cancer of the epithelial cells lining the milk ducts that carry milk from lobules to the nipples of the breast. Ductal carcinoma in situ (DCIS) is also called intraductal carcinoma and is a kind of noninvasive breast cancer.
- Lobular carcinoma: Lobular carcinoma is a type of breast cancer that develops in the lobules or ducts (milk glands) of the breast. This type of cancer is called adenocarcinoma.
- Invasive breast cancer: Breast cancer that is invasive or has spread from its origin to surrounding normal breast tissue is called invasive breast cancer.
Invasive ductal carcinoma (IDC) and invasive lobular carcinoma (ILC) are the most common types. Invasive ductal carcinoma accounts for about 70 to 80 percent of all breast cancers.
2 types of invasive breast cancer
- Triple-negative breast cancer: Triple-negative breast cancer is an aggressive form of invasive breast cancer in which cancer cells lack estrogen or progesterone receptors (ER or PR) and produce little to no HER2 protein. So, all three tests are done to detect receptors or protein negative. It accounts for about 15 percent of all breast cancers and is a tough malignancy to cure.
- Inflammatory breast cancer: Inflammatory breast cancer is a kind of aggressive invasive breast cancer in which cancer cells obstruct lymph arteries in the skin, giving the breast an inflamed appearance. It is uncommon, accounting for roughly one to five percent of all breast cancers.
3 less common breast cancers
- Paget disease: Breast Paget disease is uncommon, accounting for about one to three percent of all instances of breast cancer. It begins in the breast ducts and spreads to the nipple skin and subsequently, to the areola (the dark circle around the nipple).
- Phyllodes tumor: Phyllodes tumors are uncommon breast cancers. In contrast to carcinomas, which originate in the ducts or lobules, they develop in the connective tissue (stroma) of the breast. The majority are benign, but some are cancerous.
- Angiosarcoma: Breast sarcomas are extremely uncommon, accounting for fewer than one percent of all breast malignancies. Angiosarcoma begins in the cells that line blood and lymph arteries. It can affect either the breast tissue or the breast skin. Some may be connected to earlier radiation therapy in that location.
7 signs and symptoms of breast cancer
The signs and symptoms of breast cancer vary among women. It is crucial to understand even slight changes in the breast.
- Breast lump: Most breast lumps are not cancerous, and they are referred to as benign lumps. It is always advised to get evaluated for a breast lump by a doctor to confirm if it is benign or malignant.
- The following are the most common benign breast lumps:
- Feeling a lump is often common before every period.
- The presence of cysts or fluid-filled sacs in the breast is common.
- Fibroadenoma is mostly seen in women younger than 30 years. It is a benign breast tumor made up of both glandular and stromal tissue.
- The following are the most common benign breast lumps:
- Changes in the breast: A cancerous breast may appear larger, have a different shape than usual, and feel different. Many healthy women experience lumps and soreness in the breasts right before their menstruation. Similar changes are seen with breast cancer, so it is recommended to pay attention to the size, shape, and texture of one’s breast.
- Skin changes: Puckering, dimpling, rash, or redness of the breast skin are examples of skin changes. Some women get a rash or redness around their nipples and surrounding skin. The skin may resemble orange peel or have a distinct texture.
- Changes in nipple positioning: One of the nipples may turn in or sink into the breast. It may seem or feel different than normal. Consult the doctor if any changes out of the ordinary are seen with one or both nipples.
- Nipple discharge: Discharge from a woman’s nipple who is not pregnant or nursing could be an indication of malignancy. However, this can be caused by other medical issues.
- Breast pain: Breast discomfort is usually not caused by cancer. It is common to experience soreness in one or both breasts for a short period. Sometimes, there may not be an evident cause for the discomfort even after undergoing several tests. However, it is advisable to consult a doctor to get evaluated for breast discomfort.
- Lump in armpit: Usually, lymph nodes are not palpable unless there is any possible infection or illness. Breast cancer can spread to adjacent lymph nodes causing lumps in the armpit and even around the collar bone.
Though most of the signs and symptoms incline toward benign conditions of the breast, it is always advisable to get evaluated by a doctor and rule out malignancy.
How is breast cancer diagnosed?
Any structural changes in the breast or the presence of a lump or discomfort in the breast should be evaluated.
- Mammography: Mammography is an X-ray examination that is performed to inspect the breasts. This imaging technique includes exposing the breasts to a low dose of ionizing radiation to capture images of the interior of the breasts. It is recommended that all women aged 45 to 50 years, who are at low risk of developing breast cancers, undergo mammography one or two times each year.
- Breast ultrasound: Breast ultrasound creates images of the interior of the breasts using sound waves. Breast ultrasound can capture pictures of parts of the breast that mammography may not be able to view. It can help determine if a breast lump is solid or cystic.
- Magnetic resonance imaging (MRI): A high magnetic field, radiofrequency pulses, and a computer will be used during breast MRI to obtain detailed images of the interior of the breasts. MRI is useful to assess breast tumors that are not visible on mammography or ultrasound, especially in women with thick breast tissue.
- Positron-emission tomography/computer tomography (PET/CT): A nuclear imaging technique combines PET and CT scans to provide pictures that highlight the anatomic site of abnormal metabolic activity inside the breasts. It can identify breast cancer, determine whether it has spread, evaluate the efficacy of a treatment plan and establish whether the disease has relapsed following treatment.
- Scintimammography: Scintimammography examines a breast abnormality using small quantities of radioactive material, a special camera, and a computer. Scintimammography can identify cancer even in the presence of thick breast tissue and breast implants. It can identify whether a biopsy is necessary, hence reducing unnecessary interventions. If these tests show that a lump is benign, no further action is required. A biopsy may be required if these tests do not reveal that the lump is benign.
- Breast lump biopsy: Breast lump biopsy is a procedure where a needle is inserted into the breast lump and some tissue is extracted. This procedure can be done under the guidance of X-rays, ultrasound, or MRI. The extracted breast tissue is studied under a microscope to look for abnormal cells. If cancer is detected in a biopsy, then treatment will be administered according to the stage and location of cancer.
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5 stages of breast cancer
Breast cancer progresses through five stages. These stages are defined by the size of the tumor, the involvement of lymph nodes, and if cancer has spread to other parts of the body.
- Stage 0: Cancer is noninvasive or in situ (DCIS, LCIS). There is no sign of the spread of cancer cells. Cancer is confined to the breast tissue where it began. Paget’s disease is commonly diagnosed at stage 0.
- Stage I: Breast cancer is invasive, has modest tumor size, and has little nodal involvement.
- Stage II: The tumor size ranges from 2 to 50 mm, with or without nodal involvement.
- Stage III: The tumor is more than 50 mm in diameter, involves more than four lymph nodes, and is in the chest wall or skin.
- Stage IV: Stage IV breast cancer is also called metastatic breast cancer. Cancer has progressed to other regions of the body, including the bones, liver, and lungs, in addition to the breast and lymph nodes.
Stages I to III are further divided into subtypes based on the size of the tumor and location of distant metastasis, such as lymph nodes.
What are the treatment options for breast cancer?
Treatment for breast cancer is determined by the location of cancer, size, whether it has spread to other parts of the body, and overall health. A group of physicians and other experts decide on the best treatment to get the desired outcome.
- Surgery: Most individuals start their breast cancer treatment with surgery. There are various surgical methods, they include:
- Breast-conserving surgery: Breast-conserving surgery is referred to as wide local excision. Depending on the size and location of cancer, only the malignant lump with a border of normal breast tissue may be removed.
- Mastectomy: Mastectomy removal of the entire breast. A breast reconstruction surgery may follow mastectomy, where a muscle flap can be used to create a breast-like structure.
- Excision of lymph nodes: Breast cancer has the potential to spread to other regions of the body. It frequently spreads to the lymph nodes in the armpit (axilla) near the breast initially. They are removed while performing tumor removal from the breast, especially during mastectomy.
- Radiation therapy: High energy radiation is used to kill cancer cells in the breast. This usually follows breast conservative surgery to kill the remanent cancer cells.
- Chemotherapy: Chemotherapy drugs are injected into the veins to kill cancer cells. This is usually done after surgery. In some cases, chemotherapy is administered before surgery to shrink a large tumor for easy removal.
- Targeted cancer therapy: Targeted therapy can be administered along with chemotherapy for tumors that are caused by genetic mutations.
- Hormone therapy: Administration of estrogen and progesterone in women to disrupt cancer cells.
These treatments can be performed alone or in combination for better results.
Many women have no further difficulties following their initial breast cancer therapy. However, breast cancer can reoccur following treatment. So, it is recommended to follow up closely with a doctor regularly to evaluate for recurrence of abnormalities.
Medically Reviewed on 6/1/2022
Sun YS, Zhao Z, Yang ZN, et al. Risk Factors and Preventions of Breast Cancer. Int J Biol Sci. 2017;13(11):1387-1397. Published 2017 Nov 1. doi:10.7150/ijbs.21635
Cedars-Sinai. Breast Cancer Risk Factors: Age, Genetics & Others. https://www.cedars-sinai.org/programs/cancer/we-treat/breast/about/risk-factors.html
Breastcancer.org. Breast Cancer Risk Factors. https://www.breastcancer.org/risk/risk-factors