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 cancer is found in women more than men, with men having a very small chance of encountering it, only 1 % of all breast cancer. In 2012, the data collected from various types of cancer patients in Thailand found that the breast cancer the number 1 most prevalent cancer.
Ref: Hospital-based cancer registry annual report 2012: National Cancer Institute department of medicine services ministry of public health Thailand
Breast cancer is categorized into 4 stages, consisting of:
Stage 0 Early stage of cancer cells that have not metastasized into breast tissue.
Stage 1 The tumor is less than or equal to 2 centimeters and has not spread to lymph nodes.
Stage 2 The tumor is between 2-5 centimeters in size, which may or may not metastasize into axillary lymph nodes, or the tumor is less than 2 centimeters and has spread into axillary lymph nodes, but has not yet metastasized to other organs.
Stage 3 The tumor is larger than 5 centimeters and has metastasized into axillary lymph nodes, but has not metastasized to other organs.
Stage 4 The tumor has metastasized to other organs.
Risk factors of breast cancer
- Women previously diagnosed with breast cancer or having a family history of breast cancer, particularly in first-degree relatives, i.e., mother or sister, etc.
- Women without children or having the first child after age 30 years old.
- Women with early menarche and late menopause or who have used hormone replacement for more than 10 years.
- Women aged 40 years and older.
Diagnosis of breast cancer The combination of these assessments will be used:
Whenever abnormal symptoms are found and suspected to possibly be breast cancer, i.e. abnormalities of mammogram, tumor found by breast self-exam, or abnormality of breast, physician consultation is recommended, the physician may ask about your health history, symptoms, risk of breast cancer, and perform a general physical examination as well as a breast examination as follows:
- Physical breast exams done by either a health professional or by yourself that generally examine type and size of lumps and breast including axillary area and above clavicles.
- Mammogram and breast x-ray that provide more information, especially whether such lump is a tumor, tumor size and edge, and the number of existing tumors.
- Ultrasonography that helps differentiate between breast mass and cysts and is also used along with mammogram.
From preliminary data, the physician will determine if further investigations or treatments are needed. In patients whose investigations result is compatible with a non-serious type, the physician may schedule patients for regular visits to follow-up if there are any changes in disease lesions. In patients who are suspected to have breast cancer, needle or surgery biopsy may be needed, including:
- Fine needle aspiration biopsy:A small needle is used to examine a suspicious lump/cyst. This needle is used to aspirate fluid or to collect a suspicious breast lump, then to examine the nature of the aspirated cells by microscope.
- Core needle biopsy:A large needle is used to collect a suspicious breast lump or to remove an abnormal area found by mammogram and send to a pathology laboratory. A pathologist will determine if such cell type is a cancer cell or not.
- Surgical biopsy:All or part of a suspicious breast lump is removed by a physician. A pathologist will examine by microscope to look for cancer cells. When breast cancer is confirmed by a biopsy, special additional examination of hormone receptors is recommended to determine cancer severity and to select a treatment method which is appropriate to the signs of the disease. There are 2 types of hormone receptor, estrogen receptors and progesterone receptors. If test results are positive, it demonstrates that the disease responds to hormone therapy. If test results of HER-2 oncogene immunohistochemistry are positive, it demonstrates that such breast cancer is a serious type, resistant to chemotherapy and rapidly recurrent. In addition, patients with HER-2 oncogene positive die from cancer faster than negative ones. HER-2 oncogene can also predict the treatment response of targeted therapy.
Breast cancer treatment A team of physicians in various specialties including surgeon, radiologist, and medical oncologist, will work together in order to obtain the best treatment plan appropriate for individual patients. Factors influencing the physician to choose a treatment method include:
- Size, position, and type of cancer cells
- Disease stage and metastasis of cancer
- Age and health of patient
- Hormone receptors of cancer cells
- Pre- or post-menopause
- Factors indicating tumor severity, i.e. HER2 gene