Breast cancer is caused by cell abnormalities in lactiferous ducts or mammary glands. These cells proliferate abnormally and uncontrollably. They usually metastasize through lymph ducts into adjacent organs, i.e. axillary lymph nodes, or spread out to other distant organs including bones, lungs, liver, and brain like other cancers.

Breast consists of various components including fat cells, lobules which produce milk, and ducts which collect milk produced by lobules into nipples. All of these cells can mutate and become cancerous. However, ductal cells are where the abnormalities are most commonly found which can develop to breast cancers or also called invasive ductal carcinoma. Another type of cancer which is rarely found is the lobule cancer or also called invasive lobular carcinoma. Both types of cancer have the same treatment methods. The last type is defined as a mass found in the breast spread from another cancer located outside of breast, called metastatic carcinoma of which treatment is different from breast cancer and must be treated based on the primary cancer that will not be described in this section.

Breast cancer is still the no. 1 cancer that is most commonly found in Thai women and globally. Breast cancer found in women more than men. Men have a very rare chance of only 1% of all breast cancer. Based on data collection from patients with various types of cancers in Thailand by National Institution in 2016, it is found that breast cancer has the highest number of patients.

Causes of breast cancer

  • Genetic abnormalities: Having family history of breast cancer, especially there are higher risk in those with immediate family members having breast cancer. Breast cancer screening is recommended for women having mother, sisters, or children with breast cancer before the age 50 years.
  • Age: The older, the more chance of developing abnormal gene in the cells that could lead to cancers afterwards.
  • Early menstruation (younger than 12 years) or late menopause (older than 50 years) allows the body to be exposed to estrogen and progesterone longer than regular women.
  • Gender: Men can also develop breast cancer, but it is less likely than woman. Women have 100 times higher chance of having breast cancer as opposed to men.
  • Breast consisting of dense tissues means they have more lobules than normal women leading to higher risk. In other words, it makes more difficult for doctors to detect this abnormality by breast examination or using diagnostic devices.
  • Race: is the important factor. Western women have higher risk than Asian women.
  • History of alcohol consumption: Alcohol increases the risk of breast cancer. Women who drink more than 2-5 glass per day have 1.5 times higher risk than non-drinking women.
  • Obesity: In addition to posing higher risks of heart disease and diabetes, obesity is also associated with higher risk of breast cancer.
  • Non-breastfeeding: during breast feeding, breast-feeding mother will be free of menstruation period due to change in hormone level and this can prevent them from breast cancer.

**If you find out that you meet one of the above criteria that puts you at risk of breast cancer, you should consult your doctor immediately.

Indicative or suspected signs of breast cancer

The following symptoms may indicate that you have cancer, that you should consult doctor immediately.

  •  Palpation of solid mass in breast
  • Change in breast surface, a lump with rough surface, or unhealed wound,hard skin or change in colour
  • Breast surface present with clearly enlarged pores, which looks like orange peel, caused by cancer cells in lymphatic ducts under the skin
  • Dimples of skin around breast area
  • Dimpled nipples
  • Bleeding nipples
  • Any changes in one of the breasts.


Stage classification of breast cancer

  1. Early stage of breast cancer. Cancer is still limited within the breast area. No significant metastasis into lymph nodes in the armpits.meaning that an unusual mass is not palpable and the cancer has not spread out to any area.
  2. Advanced stage of breast cancer. This stage is likely severe, i.e. tumor size is larger than 5 cm or it has spread out to lymph nodes in the armpits, for example, palpable in the armpits, bigger or attached to tissue under, but has not metastasised to the remote organ.
  3. Metastatic stage of breast cancer is defined as the spread out of cancer to remote organs, such as lung, liver, bone, brain, etc.

Breast cancer screening

Cancer can be cured if it is detected in the early stage. Early detection is critical. Procedures which allow us to have early diagnosis of breast cancer are:

  1. Breast self-examination (BSE)
  2. Clinical breast examination (CSE)
  3. Mammography

1. Breast self-examination

  • The appropriate time for the examination
    Should check after menstruation period as breasts are less tender and easier to check for lumps than other periods of month.
  • Examination procedures
    1. Look at the mirror to see if you have the same breast size, if both nipples are in the same level, if there is any unusual dimple or lesion on the breast surface.
    2. Feel your breasts while lying down. One hand of the exam side lies under your head and place a small cloth under the shoulder to ease the examination, then feel all over your breasts using a circular motion or each part of your breast depending on your convenience. The principle is to feel all over the breast. If you find an irregular lump by hand, please see doctor for confirmation.
    3. Lastly, squeeze your nipples to see if there is any unusual fluid or blood coming out. If yes, please see doctor for further investigation.

2. Clinical breast examination

If you aged 30 years or older, you should see doctor for breast examination approximately once every 6 months to ensure that the self-examination does not miss any abnormalities. In addition, if you find any abnormalities by self-examination, you have to see doctor for further investigation as appropriate. Remember that it can be done by both male and female doctors, you should not be shy to have it done by male doctor.

3. Mammography

Mammogram machine is a special x-ray machine with one side of plate to support under your breasts and another side to press down. This method allows doctors to see abnormalities more clearly. The abnormalities detected by the mammogram machine and may be indicative of cancer include; microcalcification in the breast, solid mass, etc. Mammogram may be followed by breast ultrasound (ultrasound of breast) to look closely at the breasts in more details. Apart from breast examination, mammogram and ultrasound are also used to investigate abnormalities at armpit lymph nodes.

Diagnosis of breast cancer
Primary diagnosis: Radiological examination and biopsy

If breast lump is detected, you have to see doctor immediately. The doctor will ask you questions, performing physical examination,complete breast examination, as well as feeling of lymph nodes at armpits and neck.

Moreover, you will also receive further examination with ultrasound of breast and mammogram, which are the routine procedures. Ultrasound does not cause any pain and take long. This procedure uses sound waves transmitted through the skin and makes images under the skin. This method is used in women aged 35 years or younger since breast mass are still of high density, leading to poor quality of mammogram images. Furthermore, it can tell if there is fluid in the lumps. A bulb containing fluid inside is called cyst. Mammogram is an x-ray of breast. It is commonly used in women aged over 35 years. This procedure is very useful for the diagnosis of cancer in early stage where the lump is not palpable. It may cause some pain, because breasts will be squeezed between two iron plates and these plates will be pressed against each other. However, most women can tell that it causes fairly tight pain and harmless to the breasts. If any abnormalities are detected, biopsy will be done by doctor. Tissues obtained will be sent to pathological laboratory for diagnosis. To determine if a cancer exists, there are various procedures available to remove tissue for investigation including fine needle aspiration, core needle biopsy, and excisional biopsy.

Fine needle aspiration:

Doctor will insert a fine needle into the lump and aspirate cells for investigation. In case of lump containing fluid, it can also be obtained by this procedure.

Core needle biopsy: 

The needle used is bigger than that used in the first procedure and doctor will inject local anaesthetic to numb that area. This allows a collection of fair amount. The advantage is that it enables pathologists not only to see if there are any abnormal cells becoming cancerous, but also to see if such cancer has already spread into surrounding tissues. With that, they can identify that it is in situ breast cancer or invasive carcinoma.

Excisional biopsy: 

A small surgery to obtain the whole mass for pathological investigation.


Principles of breast cancer treatment

  1. Local treatment which includes surgery and radiation to control lesions in breasts and armpits. It is important to tell that in order to completely cure breast cancer, the tumors have to be totally removed from the body.
  2. Systemic treatments which covers all lesions are; chemotherapy or anti-hormonal agents to control cancer cells that may spread into other parts of the body.

Systemic treatment of breast cancer

Systemic treatment is available in the form of injection, oral, or subcutaneous or intra-muscular injection. In principle, once the drug is administered, it can destroy cancer cells regardless of which organs the cells are located in. Systemic treatment consists of several groups of medications including

  1. Chemotherapy
  2. Antihormonal agents
  3. Targeted therapy Immunotherapy


It is important to know that even if you have the same type of cancer as someone else, your DNA mutations may differ, and you may need different treatment. By taking a look into your cancer DNA mutations with Comprehensive Genomic Profiling, your doctor can consider this information for identifying the most appropriate treatment approach for your cancer.



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