Breast Cancer

24 October 2023

OVERVIEW

Breast cancer originates in breast tissue. It is the leading cause of cancer incidence amongst women globally, with an estimated 2.3 million new cases (11.7%) diagnosed in 2020.

Breast cancer is a complex disease that consists of different subtypes that are associated with different clinical outcomes. These subtypes are characterized by the presence/absence of cell receptors that attach to certain hormones (such as estrogen or progesterone) or high levels of the HER2 protein, all of which promote the growth of cancerous cells.

Understanding these subtypes can help determine the best treatment strategy against breast cancer. It is important to note that one of the best approaches to treat this disease is early diagnosis – when the cancer is easier to treat.

RISK FACTORS

Several risk factors could increase the likelihood of developing breast cancer, some of these include:

Gender: Breast cancer is commonly diagnosed in women
Genetic factors: Mutations of the breast cancer anti-oncogenes, BRCA-1 or BRCA-2, increases the risk of breast cancer
Age: Breast cancer incidence increases with age, with most cases being diagnosed in women over 50 years of age
Family History: The risk of breast cancer increases greatly if there is a family history (mother, sister or father) of breast cancer – especially if diagnosis occurred before the age of 50.
Reproductive health history: Reproductive factors that increase a woman’s lifetime exposure to estrogen, such as early menarche (before the age of 12), late menopause (after the age of 55), late age at first pregnancy (after the age of 30) and nulliparity can increase the breast cancer risk.

SYMPTOMS

During the early stages of breast cancer, most people do not experience symptoms; however, some symptoms that have been reported include:

A lump in the breast
Change in size, shape or appearance of the breast
Nipple abnormalities (discharge, scaliness, changes in appearance such as inward turning of the nipple or change in direction)
Breast skin abnormalities (skin redness, rash, dimpling, thickening of the skin that results in an orange-peel texture, ulceration)

In cases where the breast cancer has spread (metastasized), the symptoms usually depend on where the cancer has spread. For instance, symptoms associated with bone metastasis include pain in the joints/bone or numbness and muscle weakness in the limbs. Symptoms associated with lung metastasis include shortness of breath or cough, or frequent chest infections. Brain metastasis symptoms include seizures, headaches, mood changes, personality changes and vision changes.

DIAGNOSIS AND TYPES OF TESTS

Different tests can be used to detect and diagnose breast cancer; however, breast cancer is usually diagnosed via a routine screening mammogram. Any abnormalities on a mammogram are usually followed by other tests to aid in the diagnosis; some tests include:

Breast ultrasound: A medical imaging test that produces computer pictures of the inside of the breast, using sound waves and their echoes as they bounce off body tissues. The image produced can indicate whether the mass is fluid-filled or solid and is useful to get a better look at any abnormalities that was detected on a mammogram.

Breast MRI: A non-invasive medical imaging test that creates detailed images of almost every internal structure in the human body, using a large magnet and radio waves.

Breast biopsy: A medical procedure that involves removal of a sample of breast tissue for further analysis.

TREATMENT OPTIONS

Depending on the stage of disease, as well as patient and tumour characteristics, current breast cancer treatment options include surgery (mastectomy or lumpectomy) that is often combined with:

Radiation therapy: Radiation therapy uses powerful beams of energy to destroy cancer cells that may remain after surgery. This type of treatment is typically aimed at killing or damaging cancer cells in the area being treated.

Chemotherapy: Chemotherapy (chemo) involves the use of powerful anti-cancer drugs that target cells that are dividing rapidly. The drugs are designed to kill cancer cells, control their growth or to shrink tumors that are causing pain and other symptoms. Sometimes breast cancer patients are given chemo before surgery to shrink the tumor. Otherwise, patients are given chemo after surgery so that any cancer cells that might have been left behind are destroyed; as well as to reduce the chances of the breast cancer coming back. Despite the damaging effect of chemo on cancer cells, healthy cells in the mouth, stomach, bone marrow or hair (that also undergo rapid cell division) are also affected, which explains the adverse side effects experienced by some cancer patients.

Hormone therapy: Some breast cancers are stimulated by the action of estrogen and are known as estrogen-dependent or hormone-dependent tumors. Estrogen also amplifies the action of progesterone, a hormone that plays an essential role in the complex regulation of female reproduction. Hormone therapy reduces estrogen levels or inhibits the actions of estrogen. In breast tumors that lack receptors for estrogen or progesterone, hormone therapy is not recommended.

Targeted therapy: Some breast cancers overexpress certain characteristic proteins on their surface, which makes it possible for the cancer cells to survive, multiply and spread. Breast cancer targeted therapies are aimed at blocking or slowing the growth of cancer cells by inhibiting the function of these proteins or the genes that produce them.

Note:

It is important to know how your breasts look and feel, and to report any changes to your health care provider immediately. The importance of regular breast cancer screening measures cannot be emphasized enough – as treatment is most effective when the malignancy is detected early. Other factors such as increased health awareness, increased awareness of prevention strategies and better access to medical treatment are extremely important to limit the burden of breast cancer.

REFERENCES

Alkabban FM, Ferguson T (Updated 2022). Breast Cancer. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing. Available: https://www.ncbi.nlm.nih.gov/books/NBK482286/

Canzoniero J (no date). Metastatic Breast Cancer (Online). Available: https://www.hopkinsmedicine.org/health/conditions-and-diseases/breast-cancer/metastatic-breast-cancer Accessed: 20/10/2023.

Koo MM, von Wagner C, Abel GA, McPhail S, Rubin GP, Lyratzopoulos G (2017). Typical and atypical presenting symptoms of breast cancer and their associations with diagnostic intervals: Evidence from a national audit of cancer diagnosis. Cancer Epidemiol., 48:140-146. doi: 10.1016/j.canep.2017.04.010. Epub 2017 May 23. PMID: 28549339; PMCID: PMC5482318.

Laronga C (2023). Patient education: Breast cancer guide to diagnosis and treatment (Beyond the Basics) (online). Available: https://www.uptodate.com/contents/breast-cancer-guide-to-diagnosis-and-treatment-beyond-the-basics#disclaimerContent Accessed date: 20/10/23

Lei, S, Zheng, R, Zhang, S, Wang, S, Chen, Ru, Sun, K, et al. (2021). Global patterns of breast cancer incidence and mortality: A population-based cancer registry data analysis from 2000 to 2020. Cancer Commun, 41: 1183–1194. https://doi.org/10.1002/cac2.12207

Malherbe K, Tafti D (Updated 2023). Breast Ultrasound. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing. Available: https://www.ncbi.nlm.nih.gov/books/NBK557837/ Accessed: 21/10/2023.

Masoud V, Pagès G (2017). Targeted therapies in breast cancer: New challenges to fight against resistance. World J Clin Oncol. 8(2):120-134. doi: 10.5306/wjco.v8.i2.120. PMID: 28439493; PMCID: PMC5385433

Sheng J (2023). Hormonal therapy for breast cancer. Available: https://www.breastcancer.org/treatment/hormonal-therapy Accessed 21/10/23.

Sun YS, Zhao Z, Yang ZN, Xu F, Lu HJ, Zhu ZY, Shi W, Jiang J, Yao PP, Zhu HP (2017). Risk factors and preventions of breast cancer. Int J Biol Sci, 13(11):1387-1397. doi: 10.7150/ijbs.21635. PMID: 29209143; PMCID: PMC5715522.

Sung H, Ferlay J, Siegel RL, Laversanne M, Soerjomataram I, Jemal A, Bray F (2021). Global cancer statistics 2020: GLOBOCAN estimates of incidence and mortality worldwide for 36 cancers in 185 countries. CA Cancer J Clin, 71(3):209-249. https://doi.org/10.3322/caac.21660

The American Cancer Society Medical and Editorial Content Team (2021). Chemotherapy for breast cancer (Online). Available: https://www.cancer.org/cancer/types/breast-cancer/treatment/chemotherapy-for-breast-cancer.html Accessed: 20/10/2023

Underfirth D (2019). Breast cancer symptoms you shouldn’t ignore (Online). Available: https://www.mdanderson.org/publications/focused-on-health/breast-cancer-symptoms-you-shouldn-t-ignore.h10-1592991.html Accessed 20/10/2023.

Terms of Use

The content provided is for educational purposes and is not intended to offer personal medical advice. You should seek the advice of your physician or other qualified health providers with any questions you may have relating to a medical condition.