The common side effects include nausea and vomiting, loss of hair, stomach upset, kidney dysfunction, bone marrow suppression, tinnitus (abnormal noises in the ears) and high frequency hearing loss. Also lung disease and infertility may occur.
What is radiotherapy?
Radiotherapy involves the use of high-energy ionising radiation to cause DNA damage and ultimately cell death.
Dose of radiotherapy is measured in Grays (Gy) – this represents the amount of energy deposited in the tissue.
Radiotherapy is given in units called fractions over several day or weeks. To give the dose in one go is too toxic and would cause severe tissue damage and even death.
The area to be irradiated is referred to as the radiation field. This is always marked out on the skin before treatment and such markings often perisist after the treatment.
Each tissue in the body has a particular tolerance to radiation. This limits the total dose that can be administered to that area.
How is radiotherapy delivered?
There are three major ways in which ionising radiation is delivered.
External beam radiotherapy: This involves the use of a variety of machines to deliver external beam therapy. The source is at a distance from the body.
Brachytherapy: In this the radioactive source is in or close to the area to be treated, or directly into the tumour.
Radioactive isotope: This involves giving a radioactive isotope that is taken up by the target organ. Radioactive isotopes can be injected or given into a vein by an injection.
What are the side effects of radiotherapy?
The common side effects are skin diseases, nausea, lethargy, bone marrow suppression, dairrhoea, hair loss, lung fibrosis, kidney impairment and paralysis.
What is hormonal therapy?
Endocrine therapy (or hormonal therapy) is an important part of managing cancers whose growth is dependent on hormones, namely breast and prostate cancer. The aim of such treatment is to reduce the amount or effect of circulating sex hormones.
Hormonal manipulation is used when the breast tumour is sensitive to circulating oestradiol i.e when it is positive for oestrogen receptor.
The growth of prostatic carcinoma is under the control of male sex hormones. Hence, the aim of hormonal therapy is to reduce testosterone levels or prevent it from binding to the androgen receptor.
What is immunotherapy?
Immunotherapy stimulates the immune system to build a response to the tumour. Interferons are naturally occurring proteins produced in response to viral infections. Three interferons are known to exist alpha, beta, and gamma. Only interferon alpha is used in treatment of cancers. The adverse effects are fluid retention, multi organ dysfunction, bone marrow and liver toxicity and fatigue.
What are the different mode of treatments for cancer?
Non-surgical or medical treatments for different cancers include chemotherapy, radiotherapy, endocrine therapy and immunotherapy
What is chemotherapy?
Chemotherapy or cytotoxic agents are drugs, which interfere with cell division. They prevent cells from multiplying.
They are non-selective and will affect any cell which is rapidly dividing, whether it is cancerous or non- cancerous.
Cytotoxics are usually given in combination or with drugs which interfere with replication at different phases of the cell cycle. This improves their effectiveness and reduces the likelihood of the development drug resistance.
Chemotherapy is given every 21 to 28 days to allow recovery of the bone marrow.
Each treatment is called a cycle and usually a course of chemotherapy involves a number of cycles.
The toxicities of each agent given in combination should not overlap.