Although 90% of breast lumps are
benign (not cancer), one of the most common symptoms of breast cancer is a lump
or thickened tissue in the breast (or potentially in the axillary lymph nodes,
felt in the armpit). Other symptoms include any changes to the size, shape or
the skin of the breast, discharge from the nipple or painful breasts or
armpits. People with breast cancer symptoms then discuss them with their GP who
can refer them for screening. The NHS also runs a screening programme where
women aged 50 to 70 (the most at risk group) are invited for digital mammography.
Screening involves either a mammogram or breast ultrasound to produce an image
of the breast indicating any tumours. For younger women with denser breasts,
ultrasound scans are more effective for indicating tumours. Biopsies are used
to see if the lump is cancerous; either a few cells are removed either by using
a vacuum to aspirate though a small needle without removing any tissue, or a sample
of tissue is removed through a large needle. MRI scans can also be used to
further identify the extent of the disease of the breast and to identify the
area to be removed in surgery. Tests can also be carried out to check any metastasis
to other vital organs (using CT scans or chest X-rays) or to identify the
hormone receptor status of the tumour cells removed in biopsy.
The breast cancer screening programme
has come under fire recently. A review published in the Lancet medical journal, showed that screening can lead to overdiagnosis, as each patient has a 1% chance of being overdiagnosed if they go for screening. Overdiagnosis is the screening which identifies a cancerous growth, but one which would not have been harmful. This means that patiuents have to unnecessairly undergo treatments (which can have dangerous side effects). There are also risks of false positives where women with no breat cancer at all are told that they have the disease, which leads to the anxiety of being diagnosed with cancer.
Breast cancers are defined by their stage grade and receptor
status. The stage of the tumour tells us its size and how far it has spread. TNM
staging gives us staging bases on T, tumour size, N, whether the axaillary
lymph nodes are affected and M, whether the tumour has metastised. Ductal
carcinoma in situ is stage 0; if the tumour measures less than 2cm and the lymph nodes
in the armpit are not affected (also no metastasis) it is in stage 1; Stage 2 is
when either the tumour measures between 2cm and 5cm or the lymph nodes in the
armpit are affected, or both, with no sign that the cancer has spread elsewhere
in the body; if there are still no signs of metastasis, but the tumour measures
larger than 2cm and the lymph nodes in the axilla are affected, it is stage 3 (the
tumour might be attached to structures in the breast, such as skin or surrounding
tissue); Stage 4 describes tumours of any size where the cancer has spread to
other parts of the body (metastasis). The grade of the cancer describes the
appearance of the individual cancer cells that make up the tumour. If the cells
are slow growing, even if they look abnormal, they are G1 (low grade); If the
cells have poorer differentiation (and so look more abnormal) than G1 cells we
describe them as G2 (medium grade); G3 (high grade) cells look very abnormal
and proliferate quickly.
Cancer develops due to changes to the
genetic information in cells, mutations of oncogenes or tumour suppressor genes, which mean that there
are changes to the proteins created within cells, which allows tumours to
develop. These mutations are somatic which means they happen as the person is
alive, rather than being present in the genetic information from conception
(although some inherited alleles (versions of gene) are more likely to mutate
than others). In cancer, cells are able to evade apoptosis (organised cell
death) and anti-growth signals, or sustain their own growth and angiogenesis
(formation of a blood supply to the tumour). An example of changes in cancer
cells is a mutation causing the activation of the telomerase enzyme, which
allows unlimited replication of the cell, as telomeres do not shorten, so the
cell can undergo unlimited replications. In breast cancer, commonly inherited
mutations include BRCA1, BRCA2, TP53 and PTEN which increase the risk of the
disease. These are all tumour suppressor genes that when mutated may no longer
be able to prevent excessive cell division and proliferation.
Currently breast cancer can be treated
by: surgery to remove the tumour (breast-conserving surgey) or the entire
breast (mastectomy) and in some cases the lymph nodes from the under arm
(axilla); radiotherapy to destroy cancerous cells with targeted radiation
(often used after other treatments to remove any remaining cancer cells);
chemotherapy a treatment program which targets rapidly diving cells (such as
cancer cells but also often affecting other cells in the body such as blood
cells and hair follicles); Hormone therapy to target ER+ cancer cells with
drugs to block oestrogen (such as Tamoxifen, aromatase inhibitors or goserelin)
and biological therapy for HER2+ cancers through treatment with drugs such as
the monoclonal antibody trastuzumab (Herceptin) in addition to chemotherapy. Cancer
diagnosis is difficult to deal with and families are often offered counselling
to learn more about the illness. Additionally breast removal surgery can be
distressing for many women, as can the hair loss associated with chemotherapy, support
is offered by charity groups.
Nice (the National Institute for Health and Care Excellence) have recently approved the Oncotype DX test to identify whether breast cancer will benefit from chemotherapy treatment. This will reduce unnecessary treatment as well as the stress and side-effects associated. The test is used after surgery to see how likely a tumour is to recur (and if therefore chemotherapy needed) by looking at the activity of certain genes in the tumour. The test works best for those with ER+ cancer but HER2- cancers (without the ERBB2 receptors).
Radiotherapy can lead to skin irritation or lymphoedema (fluid build up due to the lymph nodes being blocked). Radiotherapy sessions only take a few minutes at a time, but are intensive for 3 to 5 days a week for 1 to 2 months. Chemotherapy drugs are usually administered intravenously (though in some cases they may be given in tablet form). Chemotherapy sessions usually last between 4 and 8 months, with sessions every 10-20 days. The main risks with chemotherapy is the risk of infection due to the effect on white blood cells which provide the immune response in the body, however other side effects include loss of appetite, nausea, tiredness and hair loss.
Nice (the National Institute for Health and Care Excellence) have recently approved the Oncotype DX test to identify whether breast cancer will benefit from chemotherapy treatment. This will reduce unnecessary treatment as well as the stress and side-effects associated. The test is used after surgery to see how likely a tumour is to recur (and if therefore chemotherapy needed) by looking at the activity of certain genes in the tumour. The test works best for those with ER+ cancer but HER2- cancers (without the ERBB2 receptors).
Radiotherapy can lead to skin irritation or lymphoedema (fluid build up due to the lymph nodes being blocked). Radiotherapy sessions only take a few minutes at a time, but are intensive for 3 to 5 days a week for 1 to 2 months. Chemotherapy drugs are usually administered intravenously (though in some cases they may be given in tablet form). Chemotherapy sessions usually last between 4 and 8 months, with sessions every 10-20 days. The main risks with chemotherapy is the risk of infection due to the effect on white blood cells which provide the immune response in the body, however other side effects include loss of appetite, nausea, tiredness and hair loss.
Hormone therapies are used in
conjuncture with chemotherapy, or as an alternative to other treatments (which
are too risky due to the general health of the person with breast cancer) or before
surgery to shrink the tumour so that it is easier to remove. Hormone therapies
can cause side effects like those associated with menopause such as hot
flushes, tiredness, aching joints and weight gain. Tamoxifen and aromatase inhibitors
are taken daily in tablet form, whereas goserelin is taken as an injection once
a month. Tamoxifen prevents oestrogen binding to receptors; aromatase inhibitors
prevented the production of oestrogen in women who have gone through menopause,
for whom oestrogen is produced by aromatase; goserelin is an ovarian suppressor
which prevents the production of oestrogen temporarily by the ovaries in
pre-menopausal women. Ovarian ablation is a surgical or radiotherapeutic
technique for permanent prevention of oestrogen production by the ovaries by
inducing early menopause. Monoclonal antibodies work by binding to the HER2+
receptor protein, so indicating the HER2+ cancer cells which can then be
destroyed. This treatment must be administered in hospitals via and intravenous
drip; sessions take one hour and may be as regularly as once a week. Some side effects
of trastuzumab include heart problems (so regular heart function tests are
needed) and allergic reactions to the drug causing nausea. By identifying more
genetic mutations in cancer cells we may find more ways in which we can treat
patients, using targeted biological therapies, specific to the dependencies of
their tumour.
