Breast cancer

UTG Medical Students’ Association

What is breast cancer

Breast Cancer is cancer that develops from breast tissue. It’s a disease in which cells in the breast grow out of control.

Signs and symptoms

Signs of breast cancer may include a lump in the breast, a change in breast shape, dimpling of the skin, milk rejection, fluid coming from the nipple, a newly inverted nipple, or a red or scaly patch of skin. In those with a distant spread of the disease, there may be bone pain, swollen lymph nodes, shortness of breath, or yellow skin.

Risk factors

Risk factors for developing breast cancer include:

o          obesity

o          lack of physical exercise

o          alcoholism

o          hormone replacement therapy during menopause,

o          ionizing radiation,

o          early age at first menstruation

o          having children late in life or not at all

o          older age

o          having a prior history of breast cancer

o          family history of breast cancer. About 5–10% of cases are the result of an inherited genetic predisposition. 

Breast cancer most commonly develops in cells from the lining of milk ducts and the lobules that supply these ducts with milk.

Lifestyle

Drinking Alcohol beverages increase the risk of breast cancer even among light drinkers (women drinking less than half of one alcoholic drink per day). The risk is highest among heavy drinkers. Globally, about one in 10 cases of breast cancer is caused by women drinking alcoholic beverages. Drinking alcoholic beverages is among the most common modifiable risk factors.

The correlation between obesity and breast cancer is anything but linear. Studies show that those who rapidly gain weight in adulthood are at higher risk than those who have been overweight since childhood. Likewise excess fat in the midsection seems to induce a higher risk than excess weight carried in the lower body. This implies that the food one eats is of greater importance than one’s body mass index (BMI). Dietary factors that may increase risk include a high-fat diet and obesity-related high cholesterol levels. Dietary iodine deficiency may also play a role. Evidence for fibre is unclear. Tobacco smoking appears to increase the risk of breast cancer, with the greater the amount smoked and the earlier in life that smoking began, the higher the risk. In those who are long-term smokers, the relative risk is increased by 35% to 50%.

A lack of physical activity has been linked to about 10% of cases. Sitting regularly for prolonged periods is associated with higher mortality from breast cancer. The risk is not negated by regular exercise, though it is lowered.

Hormone to treat menopause is also associated with an increased risk of breast cancer.] The use of hormones does not cause breast cancer for most women; if it has an effect, it is small (on the order of 0.01% per user–year; comparable to the rate of maternal mortality), temporary, and offset by the users’ significantly reduced risk of ovarian and endometrial cancers. Among those with a family history of breast cancer, the use of modern oral contraceptives does not appear to affect the risk of breast cancer. It is less certain whether hormonal contraceptives could increase the already high rates of breast cancer in women with mutations in the breast cancer susceptibility genes.

Breastfeeding reduces the risk of several types of cancers, including breast cancer. In the 1980s, the abortion–breast cancer hypothesis posited that induced abortion increased the risk of developing breast cancer. This hypothesis was the subject of extensive scientific inquiry, which concluded that neither miscarriages nor abortions are associated with a heightened risk for breast cancer.

Other risk factors include radiation and circadian disruptions related to shifting work and routine late-night eating. A number of chemicals have also been linked, including polychlorinated biphenyls, polycyclic aromatic hydrocarbons, and organic solvents.

Genetics

Genetics is believed to be the primary cause of 5–10% of all cases. Women whose mother was diagnosed before 50 have an increased risk of 1.7 and those whose mother was diagnosed at age 50 or after have an increased risk of 1.4. In those with zero, one or two affected relatives, the risk of breast cancer before the age of 80 is 7.8%, 13.3%, and 21.1% with subsequent mortality from the disease of 2.3%, 4.2%, and 7.6% respectively. In those with a first-degree relative with the disease, the risk of breast cancer between the age of 40 and 50 is double that of the general population.

In less than 5% of cases, genetics plays a more significant role by causing a hereditary breast–ovarian cancer syndrome. This includes those who carry the BRCA1 and BRCA2 gene mutations. These mutations account for up to 90% of the total genetic influence with a risk of breast cancer of 60–80% in those affected.

Other genetic predispositions include the density of the breast tissue and hormonal levels. Women with dense breast tissue are more likely to get tumours and are less likely to be diagnosed with breast cancer – because the dense tissue makes tumours less visible on mammograms. Furthermore, women with naturally high estrogen and progesterone levels are also at higher risk for tumour development.

Medical conditions

Breast changes like atypical ductal hyperplasia and lobular carcinoma in situ, found in benign breast conditions such as fibrocystic breast changes, are correlated with an increased breast cancer risk.

Diabetes mellitus might also increase the risk of breast cancer.

Autoimmune diseases such as lupus erythematosus seem also to increase the risk acquisition of breast cancer. 

Raised prolactin levels in the blood are associated with an increased risk of breast cancer. A meta-analysis of observational research with over two million individuals has suggested a moderate association of antipsychotic use with breast cancer, possibly mediated by prolactin-inducing properties of specific agents.

How cancer develops

Breast cancer, like other cancers, occurs because of an interaction between an environmental (external) factor and a person who is genetically at risk of developing breast cancer. Normal cells divide as many times as needed and stop. They attach to other cells and stay in place in tissues. Cells become cancerous when they lose their ability to stop dividing, attach to other cells, stay where they belong, and die at the proper time. These cancerous cells continue to grow and divide uncontrollably.

Prevention

This is mainly on lifestyle modifications.

Women can reduce their risk of breast cancer by:

o          maintaining a healthy weight,

o          reducing alcohol use,

o          increasing physical activity, and

o          breastfeeding.

The benefits of moderate exercise such as brisk walking are seen in all age groups including postmenopausal women. High levels of physical activity reduce the risk of breast cancer by about 14%. Strategies that encourage regular physical activity and reduce obesity could also have other benefits, such as reduced risks of cardiovascular disease and diabetes.

Management

The management of breast cancer depends on various factors, including the stage of cancer and the person’s age.

Treatments are more aggressive when the cancer is more advanced or there is a higher risk of recurrence of cancer following treatment.

Breast cancer is usually treated with surgery, which may be followed by chemotherapy or radiation therapy, or both.