Breast cancer is one of the most common cancers in females. In Pakistan, it is the most frequently diagnosed cancer among females, accounting for nearly one in nine female patients. Its incidence in Pakistan is 2.5 times higher than that in neighboring countries like Iran and India. Most develop in women over the age of 50 but younger women are sometimes affected. Breast cancer can also develop in men, although this is rare. Breast cancer develops from a cancerous cell which develops in the lining of a duct or lobule in one of the breasts.
Cross-section diagram of a breast
Breast tissue is attached to muscle on the chest wall. A tail of breast tissue extends up into the armpit. The breasts contain:
- Many lobules which are made up of glandular tissue. They make milk after pregnancy.
- These are channels which take milk from the lobules to the nipple.
- Fatty tissue and supporting connective tissue.
- Blood vessels, lymph channels and nerves (like all other areas of the body).
Many women find that their breasts become more lumpy and tender before periods. Breasts also alter their size and shape with increasing age, pregnancy, and with marked weight changes. What is important is that one knows her own breasts – how they look and feel – and report any changes promptly to a doctor.
Cancer is a disease of the cells in the body. in which cells become abnormal and multiply out of control.
A malignant tumour is a lump or growth of tissue made up from cancer cells which continue to multiply. Malignant tumours invade into nearby tissues and organs, which can cause damage. Malignant tumours may also spread to other parts of the body. This happens if some cells break off from the first (primary) tumour and are carried in the bloodstream or lymph channels to other parts of the body. These small groups of cells may then multiply to form secondary tumours (metastases) in one or more parts of the body. These secondary tumours may then grow, invade and damage nearby tissues, and spread again.
Breast cancer develops from a cancerous cell which develops in the lining of a duct or lobule in one of the breasts. There are some subtypes of breast cancer which are important to know, as the treatment and outlook (prognosis) vary depending on the exact type of the cancer. The following gives a rough idea of the main subtypes.
Invasive or in situ?
Most breast cancers are diagnosed when a tumour has grown from within a duct or lobule into the surrounding breast tissue. These are called invasive breast cancers. Invasive breast cancers are also divided into those where cancer cells have invaded into local blood or lymphatic vessels and those that have not.
Some people are diagnosed when the cancerous cells are still totally within a duct or lobule. These are called carcinoma in situ, as no cancer cells have grown out from their original site. Ductal carcinoma in situ (DCIS) is the most common type of non-invasive breast cancer, and about 1 in 5 new breast cancer cases will be DCIS. A carcinoma in situ is easier to treat and has a better outlook than an invasive cancer.
Grade of the cancerous cells
A sample of breast cancer tissue can be looked at under the microscope. By looking at certain features of the cells, the cancer can be graded.
- Grade 1 – the cancer cells tend to be slow-growing and less aggressive.
- Grade 2 – is a middle grade.
- Grade 3 – the cancer cells tend to be fast-growing and more aggressive.
Presence of receptors
Some breast cancer cells have receptors, which allow certain types of hormones or proteins to attach to the cancer cell. The types of receptor tested for are:
- Tests on a sample of breast cancer cells can show if they contain oestrogen receptors. Oestrogen is the female hormone. Overall, about 7 in 10 breast cancers are oestrogen receptor positive. Treatment can block the oestrogen in these cancers (see below).
- Some breast cancer cells have receptors for a protein known as HER2. Overall about 2 in 10 breast cancers are HER2-positive. Cancers having high levels of these receptors are called HER2-positive.
Stage of the cancer
This does not describe a type of cancer, but describes how much the cancer has grown and whether it has spread. As a general rule, the earlier the stage, the greater the chance of a cure (see later).
Risk factors for breast cancer
Although breast cancer can develop for no apparent reason, there are certain risk factors which increase the chance that breast cancer will develop. These include:
- The risk of developing breast cancer roughly doubles for every 10 years of age. Most cases develop in women over the age of 50.
- Where one lives. The rate of breast cancer varies between countries. This may reflect genetic or environmental factors.
- Family history of breast cancer in a first-degree relative. In particular, if they were aged under 50 when diagnosed. About 1 in 20 cases of breast cancer are caused by a faulty gene which can be inherited. The genes BRCA1 and BRCA2 are the most common faulty genes.
- If one has previously had breast cancer.
- Being childless, or if a woman had her first child after the age of thirty.
- Not having breast-fed children.
- Early age of starting periods.
- Chest being exposed to radiation.
- Having a menopause over the age of 55.
- Taking continuous combined hormone replacement therapy (HRT) for several years (in women over 50 years), leading to a slightly increased risk.
- Excess alcohol.
Breast cancer symptoms
The usual first symptom is a painless lump in the breast. Note: most breast lumps are not cancerous. Most breast lumps are fluid-filled cysts or fibroadenomas (a clumping of glandular tissue) which are benign. However, A doctor should be consulted if a lump develops, as the breast lump may be cancerous.
Other symptoms of breast cancer
Other symptoms which may be noticed in the affected breast include:
- Changes in the size or shape of a breast.
- Dimpling or thickening of some of the skin on a part of a breast.
- The nipple becoming inverted (turning in).
- Rarely, a discharge occurring from a nipple (which may be bloodstained).
- A rare type of breast cancer, causing a rash around the nipple, which can look similar to a small patch of eczema.
- Rarely, pain in a breast. Note: pain is not a usual early symptom. Many women develop painful breasts (mastalgia) and this is not usually caused by cancer.
- The first place that breast cancer usually spreads to is the lymph glands (nodes) in the armpit (axilla). If this occurs, a swelling or lump may develop in an armpit. If the cancer spreads to other parts of the body then various other symptoms can develop.
Diagnosis of breast cancer
If a lump or symptoms develops which may be breast cancer, a doctor will usually examine the breasts and armpits to look for any lumps or other changes. Sometimes a biopsy of an obvious lump is arranged, but other tests may be done first such as:
- This is a special X-ray of the breast tissue.
- Ultrasound scan of the breast.
- MRI scan of the breast. This is more commonly performed on younger women, who may have denser breast tissue.
Biopsy – to confirm the diagnosis
A biopsy is when a small sample of tissue is removed from a part of the body. The sample is examined under the microscope, to look for abnormal cells. A specialist may take a biopsy with a needle which is inserted into the lump for some cells to be withdrawn. Sometimes the doctor may be guided as to where to insert the needle with the help of a mammogram or ultrasound scan. Sometimes a small operation is needed to obtain a biopsy sample.
The biopsy sample can confirm or rule out breast cancer. Also the cells from a tumour can be assessed and tested to determine their grade and receptor status.
Assessing the extent and spread
If breast cancer is confirmed, further tests may be needed to assess if it has spread. For example, blood tests, an ultrasound scan of the liver, chest X-ray, a bone scan or other types of scan. This assessment is called staging of the cancer. The aim of staging is to find out:
- How large the tumour has grown.
- Whether the cancer has spread to local lymph nodes in the armpit.
- Whether the cancer has spread to other areas of the body (metastasised).
Finding out the stage of the cancer, the grade of the cells and the receptor status of the cancer, helps doctors to advise on the best treatment options. It also gives a reasonable indication of outlook.
Treatment for breast cancer
Treatment options which may be considered include surgery, chemotherapy, radiotherapy and hormone treatment. Often a combination of two or more of these treatments is used. The treatments used depend on:
- The cancer itself – its size and stage (whether it has spread), the grade of the cancer cells, and whether it is hormone responsive or contains HER2 receptors; AND
- The woman with the cancer – age, menopausal or not, general health and personal preferences for treatment.
The types of operation which may be considered are:
- Breast-conserving surgery. This is often an option if the tumour is not too big. A lumpectomy (or wide local excision) is one type of operation where just the tumour and some surrounding breast tissue are removed. It is usual to have radiotherapy following this operation. This aims to kill any cancer cells which may have been left in the breast tissue.
- Removal of the affected breast (mastectomy). This may be necessary if there is a large tumour or a tumour in the middle of the breast. It is often possible to have breast reconstructive surgery to create a new breast following a mastectomy.
- A sentinel lymph node biopsy may be performed. This is a way of assessing if the main lymph nodes draining the breast contain cancer. If they are clear then the remaining lymph nodes in the armpit will not need to be removed. If it is not possible to do this, one or more of the lymph nodes in the armpit may be removed. This helps to stage the disease accurately and to guide the specialist as to what treatment to advise following surgery.
Radiotherapy is a treatment which uses high-energy beams of radiation which are focused on cancerous tissue. This kills cancer cells, or stops cancer cells from multiplying. For breast cancer, radiotherapy is mainly used in addition to surgery. For example, if you have breast-conserving surgery it is usual to have radiotherapy to the affected breast after the operation. This aims to prevent breast cancer returning in the same breast.
Some types of breast cancer are affected by the female hormones oestrogen and progesterone. These hormones stimulate the cancer cells to divide and multiply. Treatments which reduce the level of these hormones, or prevent them from working, are commonly used in people with breast cancer.
Hormone treatment works best in women with hormone-responsive breast cancer, but they sometimes work in cancers classed as non-hormone-responsive.
Chemotherapy is a treatment of cancer by using anti-cancer medicines which kill cancer cells, or stop them from multiplying
Chemotherapy is sometimes given before surgery to shrink a tumour so that surgery may have a better chance of success and also a smaller operation may be performed.
Chemotherapy may also be used for some women to treat breast cancer which has spread to other areas of the body.
In summary the treatment plan that may be advised can vary greatly from case to case as optimal treatment can depend on many different factors.
Screening for breast cancer
Women between 50 and 70 are recommended to have a routine mammography every three years.
Genetic testing and mammography screening (and preventive treatments in some cases) may also be offered to younger women with a strong family history of breast cancer. Prevention
All women of every age should be breast aware. That is, they should know how their breasts and nipples normally look and feel and try to recognise any changes that occur before and after periods. If any changes, lumps, or other abnormalities in the breasts or nipples are noticed then a doctor should be consulted immediately.
There is some evidence that regular exercise may reduce the risk of breast cancer by as much as a third. For women who have been through the menopause, it is particularly important not to be overweight or obese. This is because being overweight causes more oestrogen to be produced, which can increase the risk of breast cancer.
The outlook has greatly improved in recent years. Deaths from breast cancer are now at the lowest ever in 40 years. This is mainly due to the improvements in the treatment of breast cancer. The outlook is best in those who are diagnosed when the cancer is still small, and has not spread. More breast cancers are also now being diagnosed and treated at an early stage. In general, the more advanced the cancer (the more it has spread) then the less chance that treatment will be curative.