What is breast cancer?
Breast cancer is an uncontrolled growth of cancerous cells in the breast. To better understand the disease, it helps to understand how cancer in general develops.
Cancer occurs as a result of abnormalities (mutations) in the genes responsible for controlling the growth and maintaining the health of cells. These genes are present in each and every cell in our bodies. Normally cell growth occurs via an orderly process when healthy new cells replace old or defective ones. Unfortunately, over time, mutations can alter the genes in our cells that control growth/replication of a cell. That altered cell then gains the ability to keep dividing with the body being unable to control or inhibit the process, producing more cells exactly like it and forming a growth (tumour).
A tumour can be benign (rarely dangerous to health) or malignant (cancer). Benign tumours are not cancerous, their cells closely resemble the original cell in appearance, they grow slowly, and they do not invade nearby tissues or spread to other distant organs of the body. Malignant tumors are cancerous. Growth of these cancer cells is usually much faster than in a benign tumour, their appearance can alter substantially from the original cell, and their behaviour is less predictable. These cancer cells can eventually spread beyond the original tumour to other organs in the body (metastatic disease).
The term “breast cancer” refers to a cancerous growth or tumour that has developed from cells in the breast. Breast cancer can either begin in the cells of the lobules of the milk-producing glands (lobular breast cancer), or in the ducts that drain milk from the glands to the nipple (ductal breast cancer). Less commonly, breast cancer can begin in the ‘in-between’ or stromal tissues, which include the fatty and fibrous tissue that connects the different glands of the breast (i.e. Phylloides tumour).
What are the related symptoms of breast cancer?
Breast cancer may cause a variety of symptoms which may include:
If left unchecked, cancer cells can invade nearby healthy breast tissue and invade lymphatic channels and blood vessels. The underarm lymph nodes (glands) would be the first structures that filter the lymphatic channels draining the breasts. Cancer tumour cells trapped here will present as enlarged glands in the armpit and implies a more advanced stage of cancer. If cancer cells invade the blood vessels, they then have a pathway into other parts of the body. Distant organs mostly affected would be the liver, lungs, bone and occasionally the brain. Once cancer has spread to these distant organs, the patient has metastatic disease. This implies very advanced cancer and generally carries a poor prognosis.
What are the risk factors for developing breast cancer?
Breast cancer is always caused by a genetic abnormality or aberration (a “mistake” in the genetic material). Mostly (90%) breast cancers are due to genetic abnormalities that occur as a result of the normal ageing process and the “wear and tear” of the cell. However, 5-10% of cancers are due to an inherited abnormality.
A risk factor is any factor that makes it more likely that you will get a certain disease, such as cancer—having one or even many risk factor does not necessarily mean that you will get cancer. Most women with no apparent risk factors for getting breast cancer will develop the disease, whereas most women who have one or more breast cancer risk factors will never develop the disease.
There are different kinds of risk factors. Some factors, like a person's age or race, can't be changed and are therefore termed ‘non-preventable’. Others are linked to cancer-inducing environmental factors, and some are related to personal behaviours such as smoking, excessive alcohol intake and an unhealthy diet. These factors are termed 'preventable'.
Non-preventable risk factors:
Genetic screening for breast cancer:
More and more women are deciding to learn whether or not they have an abnormality in what has come to be known as the "breast cancer genes,” BRCA1 (BReastCAncer gene 1) and BRCA2 (BReastCAncer gene 2). Women who inherit a mutation in either of these genes — from their mothers or their fathers — have a much higher-than-average risk of developing breast cancer and ovarian cancer. Men with these mutations have an increased risk of breast cancer, especially if the BRCA2 gene is affected, and possibly of prostate cancer. Many inherited cases of breast cancer have been associated with these two genes.
The function of the BRCA genes is to keep breast cells growing normally and prevent any cancer cell growth. But when these genes contain the mutations that are passed from generation to generation, they do not function normally, and breast cancer risk increases. Abnormal BRCA1 and BRCA2 genes may account for up to 5 – 10% of all breast cancers, or 1 out of every 10 – 20 cases.
Most people who develop breast cancer have no family history of the disease. However, when a strong family history of breast and/or ovarian cancer is present, there may be a reason to believe that a person has inherited a BRCA1 or BRCA2 mutation. Some people choose to undergo genetic testing to find out. A genetic test involves giving a blood sample that can be analysed to pick up any abnormalities in these genes.
The decision to have a genetic screening test is a complex one to make. A positive result will have far-reaching implications for the patient in terms of raising the possibility of prophylactic mastectomies and oophorectomy as well as possible implications with regards to life insurance policies, etc. A positive result will also have consequences for siblings and offspring. Therefore the decision to have a genetic test must preferably be made in conjunction with your surgeon and genetic counsellor and with the support of your family.
How is breast cancer diagnosed?
The most reliable way to diagnose breast cancer is to use a combination of modalities, sometimes also referred to as the 'triple test'. This consists first and foremost of a thorough history and clinical examination, followed by a mammogram and lastly a 'fine needle aspiration' (FNA) to obtain cells from the suspicious area of breast tissue. This will lead to a diagnosis in the majority of cases. In a few special instances, Dr Cooper may substitute the mammogram for a breast MRI scan or the FNA for a larger biopsy of the tumour.
What happens once I am diagnosed with breast cancer?
Once the diagnosis is confirmed, Dr Cooper will determine the severity of the breast cancer, both locally (in the breast itself) and also systemically, (whether the disease has spread to other organs). This process is commonly referred to as staging of the cancer. The local staging of the cancer and also whether lymph nodes (glands) in the axilla (armpit) are involved can be readily determined by physical examination. To determine whether systemic spread has occurred, Dr Cooper will request a CT scan of your chest and abdomen as well as a bone scan.
How is breast cancer treated?
Breast cancer is one of the most studied diseases in the field of medicine. This has led to a large body of scientific evidence that helps to guide the treatment of breast cancer. However, every patient will still have her/his treatment individualized to ensure the best possible outcome for them. These decisions are usually best made by a multi-disciplinary team consisting of a radiologist, surgeon and an oncologist, taking into account the patient’s personal preferences. In broad terms, breast cancer treatment can be divided into local and systemic therapy.
Local therapy includes the treatment of the breast itself as well as the axilla (armpit). Breast cancer has been traditionally treated with a total mastectomy (removal of all the breast tissue, skin and nipple-areola). We now know that this is not necessary in all cases. As long as certain prerequisites are met a tumour excision coupled with local breast irradiation (breast conservation therapy) can offer similar cure rates to a mastectomy. There may however be contraindications to breast-conserving therapy, which will be explained to you by your surgeon, should they be applicable. Treatment of the axilla depends largely on whether there are lymph nodes (glands) palpable or not.
In the presence of palpable glands, a standard axillary dissection is routinely performed to remove all the lymph nodes in the axilla. This is done to control the axillary disease as well as to gain information to help guide the systemic treatment of the disease.
In the absence of palpable glands, Dr Cooper will perform a sentinel lymph node biopsy. The sentinel node is the first node in the axilla draining the breast. If this node is free of cancer, there is very little chance that the other axillary nodes will be involved. The sentinel node is identified by injecting a special radioactive substance into the tumour or behind the nipple. Following this, the patient is taken to theatre, and the sentinel node (which will concentrate the radioactive marker) is identified with a gamma camera and resected. After full histological examination, a decision will then be made whether to proceed with an axillary dissection.
Radiotherapy (irradiation) is also employed to reduce the local recurrence rate of cancer. This is usually administered to the operative field after the wound has healed.
Although breast cancer always starts off as a local growth in the breast, it will at some stage spread to the rest of the body. Even if all the screening tests for cancer spread is clear, it is mostly advisable to still treat systemically (the whole body/patient) except in cases where the cancer is really detected very early. The systemic treatment has 3 components:
Chemotherapy is the use of specific cancer-killing drugs given either intravenously or orally in an attempt to treat the patient systemically (whole-body). The aim is to 'kill off' cancer cells that have escaped from the primary cancer but are as yet clinically undetectable. This can be done either in combination with surgery (as is mostly done) to cure the patient, or it can be used alone in cases where cure is not possible (the aim here would be to delay the progression of cancer). If used in conjunction with surgery it can be given either before (neoadjuvant therapy) or after (adjuvant therapy) surgery. There is no survival difference in giving chemotherapy before or after surgery. Giving chemotherapy before surgery may shrink larger tumours so that breast conservation surgery might be possible. The other advantage is that the response to the chemotherapy drugs can be evaluated clinically. If the tumour does not shrink with the first set of drugs, the oncologist may prescribe other chemotherapy drugs. These days there are a variety of chemotherapy drugs available, and multiple drugs are usually given in combination. Which combination is best, is still to be determined and remains an ongoing theme for laboratory studies and clinical trials.
Chemotherapy drugs attack cells that divide quickly, which is why they are effective against cancer cells. Other cells in the body such as the bone marrow, the lining of the mouth and intestines and the hair follicles, also divide quickly. These cells will also be affected by chemotherapy, which is why side effects develop. The severity of side effects is difficult to predict and will depend on the type of drugs used, the amount given, and the length of the treatment. The most common of the possible side effects include:
Chemotherapy is usually given in cycles, with each period of treatment followed by a period of rest where the body is given time to recover. The total length of chemotherapy is usually between 3 – 6 months, but will be determined by your oncologist and also guided by your response to the therapy.
Immunological (targeted) therapy:
Breast cancer is one of the most studied diseases of our time. This has lead to a much better understanding of the changes that occur at a genetic level when breast cancer develops.
This understanding has made it possible for scientists to develop newer drugs that specifically target these changes. The development of these drugs represents a new avenue of attack in the treatment of breast cancer and also has the advantage of fewer and less severe side effects when compared to conventional chemotherapy.
Unfortunately, not all cancers will respond to immunological therapy. Only 1 in 5 cancers will have larger than normal amounts of the growth-promoting protein known as HER2/neu (or just HER2) expressed on the surface of their tumour cells. Trastuzumab is a type of drug known as a monoclonal antibody — a man-made version of a very specific immune system protein. When the HER2 receptor is present (this can be tested for) Trastuzumab will bind to it and help slow the growth of the tumour. It can also stimulate the patient's own immune system to better fight cancer.
Breast Reconstruction following Mastectomy
Breast reconstruction is usually done by a plastic surgeon. It can be done at the time of the mastectomy (immediate reconstruction), or it can be done at a later stage (delayed reconstruction). It can be done using the patient’s own tissue also referred to as autologous (own tissue) flap surgery or it can be done with the help of breast implants. Deciding which of these options is best for you will depend on a number of clinical factors as well as your own personal preference.