Breast cancer is the abnormal growth of breast cells which invades and destroys surrounding tissue and may spread to other parts of the body. It is also referred to as a malignancy or malignant breast tumor and must be differentiated from a benign tumor which is abnormal mass of normal cells that is less serious in nature. Breast cancer remains one of the most common malignancies in women, particularly those residing in Western countries, and may very rarely occur in men.
Early diagnosis is the key to successful treatment and screening programs are now in place in most developed and many developing nations. Self-examination of the breast is of utmost importance in early diagnosis. Women are therefore encouraged to learn basic techniques for effective self-examination, identify any abnormal breast lumps and report it to a medical professional as soon as possible.
However, many tumors are missed in the early stages, even during a physical examination by a doctor. Other diagnostic investigations are essential both as a routine screening practice and as a more definitive assessment of a malignancy.
Diagnosis of Breast Cancer
History and Physical Examination
As with most other medical conditions, a through case history is important to identify symptoms of breast cancer. Warning signs may include any recent changes in the breast and nipple discharge. Risk factors may also be identified by taking a proper history.
Physical examination is not always reliable in the early stages when compared to diagnostic investigations like a mammography. Even so, regular self breast examination from the age of 20 years is advocated as a means of detecting early breast cancer and may be effective in some cases.
Mammography is an x-ray of the breast tissue. It helps in screening for breast cancer or to identify the breast tumor. Early breast cancer can be identified by mammography even before it can be palpated by a clinical examination. Treatment at this stage usually yields very good results.
Ultrasonography is used to determine whether the tumor is solid or cystic. Cystic tumors are usually not cancerous but a solid tumor may be cancerous.
CT Scan and MRI
A CT (computed tomography) scan utilizes a series of x-rays to create a cross section image of the breast. Magnetic resonance imaging (MRI) is the use of a magnetic field and radio waves to create three-dimensional images of the breast. Both CT scan and MRI are not done routinely but may sometimes be utilized to identify a lump or to assess the spread of the disease.
Breast Tissue Biopsy
A biopsy removes tissue from the breast which can then be examined by a pathologist to detect any abnormalities in cell architecture or growth. A number of techniques may be utilized in this regard, including :
- Fine needle aspiration (FNA) cytology where an extremely thin needle is used to remove cells or fluid from a lump.
- Core biopsy where a wide-bore needle is used to remove a sample of the breast tissue.
- Surgical biopsy includes incisional biopsy, where a part of the tumor is removed for examination under the microscope, and excision biopsy, where the whole tumor is removed and sent for biopsy.
- A skin biopsy may be done if there are skin changes in the breast.
- Sentinel lymph node biopsy may be done to determine spread of cancer. The lymph node draining the segment of breast where the tumor has formed is removed and a biopsy done. If cancer is found in the sentinel lymph node, it is presumed that metastasis has occurred to the other lymph nodes as well.
A biopsy is the only method that can confirm the presence of cancer in a tumor. If the biopsy confirms cancer, the tissue may be tested for hormone receptors, which are sites on the surface of tumor cells that bind to hormones such as estrogen or progesterone. More receptors indicate more sensitivity of the tumor to hormone therapy. Measurement of HER 2/neu receptors may help in characterizing a tumor and decide on the best form of treatment for that tumor. Read on
Staging and Grading of Breast Cancer
Staging of a tumor is done at the time of diagnosis for a number of reasons :
- To decide on the appropriate treatment for that particular individual.
- To get a fair idea about the outlook (prognosis).
- To compare similar cases during clinical trials.
- For accurate documentation of the initial tumor.
Staging may be done by 3 methods – clinical, pathological, and histological.
- Stage 1 : The tumor is less than 2 cm in size. It is not fixed to muscle or chest wall (N0).
- Stage 2 : The tumor is 2 to 5 cm in size. Mobile axillary (armpit) lymph nodes present on the same side (N1).
- Stage 3 : The tumor is more than 5 cm in size. It is fixed to the skin or muscle. Fixed axillary lymph nodes on the same side (N2), supraclavicular nodes (N3).
- Stage 4 : The tumor may be of any size, but fixed to skin or chest wall. Lymph nodes are involved. Distant metastasis to liver, lungs, brain, or bones present.
This is mostly done during clinical trials and is known as the TNM classification. It is a simple classification based on the size and local invasion of the tumor (T), spread to lymph nodes (N), and the presence or absence of distant metastasis (M).
This is based on the microscopic appearance of the tumor. The degree of differentiation of the tumor may give a guide to the behavior of the tumor. Grade 1 tumors are usually slow-growing and grade 4 the most aggressive.
- Grade 1 : This represents the least malignant tumors.
- Grade 2 : 25 to 50 % of the cells are undifferentiated.
- Grade 3 : 50 to 75 % of the cells are undifferentiated.
- Grade 4 : More than 75% of the cells are undifferentiated.
Staging may be done by means of the following tests
- Blood tests – may include complete blood count (CBC), liver function test (LFT), serum calcium.
- Chest x-ray.
- CT scan.
- FNAC and CT-guided needle aspiration cytology.
- Isotope scanning.
- Bone isotope scan.
- Bone marrow examination.
A combination of tumor size, grade, and lymph node involvement decides the outlook of a case, with the most important factor being nodal status.
- Stage 0 or cancer in situ has a 5-year survival rate of 99 to 100%.
- The outlook for stage 1 tumor is also very good, with a 5-year survival rate of 95 to 100%.
- The 5-year survival rate for stage 2 tumor is about 86%.
- Stage 3 tumors show a 5-year survival rate of about 57%.
- The 5-year survival rate for stage 4 tumor may be 20%.
The 5-year survival rate is the percentage of patients who live at least 5 years after being diagnosed with cancer. This is a standard way of estimating a cancer patient’s outlook. Patients may live well beyond 5 years and this should not discourage a person from continuing to seek medical treatment, adhering to the prescribed treatment and maintaining a positive attitude in this time.