• Camelia Brande

Breast cancer. Risk factors

October is Breast Cancer Awareness month, so we decided to share with you a sequence of articles about this topic. Breast cancer is the most frequent cancer and the most common cause of death among women. It is a global public health problem with consequences also on socio economic level If numbers increase in the same manner as in the present, it is estimated that by 2050 there will be 3.2 new million cases per year.


Breast cancer is a heterogeneous group of tumors. This heterogeneity (non-uniformity) is caused by several reasons. The cancer can affect various components of the breast, such as the milk ducts, milk lobules or the tissue in between. The cancer develops differently among patients, therefore the treatment also varies.

There are several types of breast cancer depending on the affected parts of the breast:

- Ductal carcinoma in situ (DCIS): it develops inside of milk ducts

- Invasive or infiltrating breast cancer: cancer cells spread outside the ducts and lobules

- Invasive ductal carcinoma (IDC): the cancer grows inside the milk ducts and spreads around the fatty tissue; it is the most common type of breast cancer and it is responsible for 80% of all breast cancers

- Invasive lobular carcinoma (ILC): the cancer grows inside the milk lobules and spreads around the lobules as well; it is the second most common type of breast cancer

- Metastatic breast cancer: the most advanced stage of breast cancer that has spread to other organs

Source


Breast cancer facts

  • It impacts over 2 million women every year

  • 140/184 countries have breast cancer as the most frequently diagnosed cancer among women

  • patients with breast cancer have more chances of survival as breast tissue is not an essential organ for survival

  • it has a higher prevalence in developed countries than in developing ones, but the mortality rate is the same

  • in developing countries, mortality is higher in relation to the prevalence, and one explanation is the socio economic context; in poorer countries there are lower cancer screening rates and more women without health insurance

  • it is expected that in the future, the prevalence of breast cancer will rise in developing countries as the people there are starting to adopt a more Western lifestyle (less physical activity, late childbearing)

  • males can have breast cancer as well, but they have a lower risk and make up for less than 1% of all breast cancer patients


Risk factors

Up to 85 % of cancers do not develop because of family history, but due to a gene modification because of lifestyle factors and age.



1. Biological sex

  • By just being a woman the risks of developing breast cancer increases up to 100x more than in the case of a man

2. Genetics and family history

  • Around 5-10% breast cancers are connected to faulty genes inherited by a parent

  • The parents can be just carriers, therefore these mutated genes may be passed to children without the parents ever developing breast cancer

  • The risk of cancer increases proportionally with the number of family members having breast cancer

  • Even women that have a father or a brother with breast cancer have a higher risk of developing it themselves

3. Benign breast conditions

  • By benign we refer to a mass that is not cancer

  • This benign condition includes cysts, nodules, and can increase the risks of developing breast cancer

  • Women with dense breasts on mammogram have up to 2 times more risks of developing breast cancer than those with average breast density;

  • The density of breast can change over time, due to age, menopause, drug treatments and pregnancy

4. Chest radiation therapy

  • Women who were treated with radiation for another type of cancer when they were younger, have a higher risk of developing breast cancer

  • This risk is even higher in children that underwent radiation, as breasts are still developing in that period

  • Radiation in women after 40 does not increase the risk of developing breast cancer

5. Exposure to diethylstilbestrol (DES)

  • Between the 40s-70s pregnant women were recommended to take DES as it was considered to decrease the risk of miscarriage

  • These women and even their children have a slightly higher risk to develop breast cancer than women that did not take this drug

6. Hormonal contraceptives

  • Women that use oral contraceptives have a higher risk of developing breast cancer, but this extra risk is assumed to lower when the contraception is stopped

  • Theoretically all contraceptives that include hormones (implants, IUD, patches and vaginal rings) may have a higher risk, therefore it is very important to talk with your physician about other risk factors of developing breast cancer

7. Hormone replacement therapy (HRT) after menopause

  • The combination of estrogen and progesterone is used to relieve the symptoms of menopause and to prevent osteoporosis (bone density decreases because of dropping estrogen levels) but increases the risks of developing breast cancer in menopausal women

  • Estrogen promotes abnormal cell growth that can turn into breast cancer

  • The risk increases with longer duration of use

  • The combination is preferred because using estrogen alone, increases the risks of developing uterine cancer

  • Women that had a hysterectomy (total removal of the uterus) can receive only estrogen, not necessarily the combination

  • The use of HRT should be decided with the physician after analyzing the risk-benefit ratio

8. Excessive alcohol consumption

  • The alcohol intake is directly proportional with a higher risk of developing breast cancer

  • Women that have 2-3 drinks per day have 20% higher risks of developing breast cancer than women that do not drink at all

  • Women that drink only one glass per day have a very small increase in risk

  • This factor is not completely conclusive, as other studies do not perceive a relation between alcohol intake and breast cancer

9. Overweight

  • Having a higher level of fat in combination with menopause increases the risks of developing breast cancer because, after menopause, the fat tissue will produce estrogen while the ovaries will stop producing it

  • Having more fat tissue will raise the levels of estrogen and increase the risk even though the connection is not fully understood

10. Not having children or not breastfeeding

  • Women that have not had children or that have had them after the age of 30, have a slightly higher risk of developing breast cancer

  • Women that have their first child at 30 have 2 times higher risk of developing breast cancer than women that have their first child before 20

  • Having multiple pregnancies, giving birth at a younger age and breastfeeding up to 2 years are supposed to decrease the risks of developing breast cancer. The explanation might be, that in this context, the number of lifetime menstrual cycles is reduced and that during pregnancy the breast tissue is suffering transformations that offer protection

11. Menstruation at a younger age and menopause at a later age

  • In both cases, earlier first menstruation (before 12) and later menopause (after 55), the woman will have a higher number of lifetime menstruation cycles, therefore increasing the chances of developing breast cancer

12. Lack of physical activity

  • Even though it is not completely elucidated, it is believed that the lack of activity may increase the risk of developing breast cancer indirectly.

  • Regular physical exercises especially in menopausal women, is thought to decrease the risk of developing breast cancer


Studies suggest that the prevalence and the mortality, due to breast cancer, will increase in the future. As current researchers are continuously working on developing better treatments, for now the key is prevention by lowering our risk factors. In our next article we will talk more about current diagnosis methods, prevention and treatments.

In the meantime, check our previous article about breast self examination.


Be smart. Be (c)LIT. Fly with us!🌺🐝

#breastcancer #breastcancerawarnessmonth #menopause #cancerfactors #breast


Sources:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6147049/

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1118507/

https://pubmed.ncbi.nlm.nih.gov/25543329/

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2815713/

https://www.nejm.org/doi/full/10.1056/NEJMc1800054



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