Radiation is a highly targeted and highly effective way to destroy cancer cells. Radiation therapy is a localised treatment which only affects the part of your body that requires treatment. High-energy X-rays and gamma rays are some of the types of radiation used for cancer treatment.
Radiation may be delivered by a machine outside the body (external-beam radiation therapy), or it may come from radioactive material placed in the body near cancer cells (internal radiation therapy, also called brachytherapy).
Despite what many people fear, radiation therapy is relatively easy to tolerate and its side effects are limited to the treated area.
About half of all cancer patients receive some form of radiation therapy sometime during their treatment. Most of the time radiation therapy needs to be delivered over several days or weeks. Most of our patients spend about half an hour each day, and are otherwise able to maintain their usual activities.
Types of Radiation
In external radiation therapy, a machine called a linear accelerator (LINAC) directs a beam of radiation through the skin of the tumor. The machine does not touch you but rotates around you, sending delivering radiation to your body from different directions. With the use of state-of-the-art treatment techniques and equipment, high dosage of radiation is aimed and shaped according to the contour of your tumor which ensuring doses to your surrounding healthy tissues and kept at a minimum.
3-Dimensional Conformal Radiation Therapy (3D-CRT)
3-Dimensional Conformal Radiation Therapy (3D-CRT) delivers a conformal radiation dose from different directions to the tumor, while sparing surrounding normal structures.
Conformal Radiation Therapy uses a specialised planning CT scanner and sometimes other scans, such as MRI scans. This means the treatment team can plan the radiotherapy treatment area very precisely in 3 dimensions – width, height and depth.
Intensity-modulated radiation therapy (IMRT)
Intensity modulated radiotherapy (IMRT) is an advanced type of conformal radiation therapy. It uses sophisticated software and hardware to vary the shape and intensity of radiation delivered to different parts of the treatment area. It is one of the most precise forms of external beam radiation therapy available. It is very helpful in areas such as the head and neck, for example to avoid the spinal cord or salivary glands.
Volumetric modulated arc therapy (VMAT)
Volumetric modulated arc therapy (VMAT) is a type of IMRT and works by delivering a continuous beam of radiotherapy in an arc which moves around the tumour, changing the beam shape and treatment dose automatically as it moves.
Treatment sessions with VMAT are significantly shorter, reducing patient discomfort and patient movement during prolonged treatment.
Stereotactic Radiosurgery (SRS)
Stereotactic radiosurgery (SRS), sometimes called radiosurgery, involves the delivery of a high dose of focused radiation therapy to a small, well-defined area in the brain or other part of the head. This is usually delivered in one, or few treatment sessions.
Despite the name, SRS does not involve actual surgery. It is called ‘surgery’ because a result similar to an actual surgical procedure is created by one therapy session. It is a non-invasive treatment for some patients with tumours or cancers of the brain and head.
SRS may be used to treat patients with secondary cancers that have moved spread to the brain (brain metastasis), slow growing benign tumours (such as acoustic neuromas), and sometimes to re-treat an area that has previously had radiation therapy before (head and neck cancers or primary brain cancers). In addition, SRS can also be used to treat some non-cancer or tumour conditions such as arteriovenous malformations (abnormal connection of veins and arteries) and complex cases of trigeminal neuralgia.
Stereotactic Body Radiotherapy (SBRT)
When SRS is used to treat body tumors, it’s called stereotactic body radiotherapy (SBRT). SBRT can deliver very high doses of radiation over a relatively short total treatment time resulting in an increased probability of local tumor control. This advanced technology treatment can be applied for the treatment of small lung cancers and control of liver tumors and selected spinal metastases.
Imaged Guided Radiation Therapy (IGRT)
Image-guided radiation therapy (IGRT) is the use of imaging during radiation therapy to improve the precision and accuracy of treatment delivery. IGRT is used to treat tumors in areas of the body that move, such as the lungs. Radiation therapy machines are equipped with imaging technology to allow your doctor to image the tumor before and during treatment. By comparing these images to the reference images taken during CT simulation, the patient’s position and/or the radiation beams may be adjusted to more precisely target the radiation dose to the tumor. Some IGRT procedures may use fiducial markers, to help align and target the radiation equipment.
Brachytherapy is a procedure that involves placing radioactive material inside your body to treat cancer. It allows your doctor to use a higher total dose of radiation to treat a smaller area in shorter time than conventional external beam radiation therapy (EBRT).
Brachytherapy is shown to be effective in combination with external beam radiotherapy and chemotherapy. The accurate delivery of radiation directly to the tumour inside the body reduces the risks of side effects.
Brachytherapy can be given over a short period of time – often a matter of day and is an established, treatment. However, it is continually being advanced with the very latest technology to provide even more effective treatment.
Intraoperative Radiation Therapy (IORT)
Intraoperative radiation therapy (IORT) delivers a concentrated dose of radiation therapy to a tumor bed during surgery. This advanced technology may help kill microscopic disease, reduce radiation treatment times or provide an added radiation "boost."
This innovative therapy is administered at the time of surgery, following cancer removal. Typically, standard radiation therapy involves five days of treatment per week, for a total of five to six weeks for some patients. With IORT, clinical oncologists can deliver a similar dose of radiation in a single treatment session, while also preserving more healthy tissue. This helps to reduce side effects and the time spent going back and forth to the hospital for radiation treatments.
A patient must be a surgical candidate to be eligible for IORT. Do consult with your oncologist to find out if you fit the criteria.
General side effects
Every individual responds and reacts differently to radiotherapy. Given this, radiotherapy affects each one differently. Some people may have mild side effects and others encounter more severe side effects. The side effects can range from medium short term to long term, depending on the individual and the cancer affected.
Some of the main side effects experienced by patients include:
One main side effect is fatigue or feeling tired and weak after treatment, more so if patients undergo treatment over several weeks. Tiredness could also be due to low levels of red blood cells (anaemia).
Feeling an overall weakness is also common, and this may last for a few weeks post-treatment. Patients are encouraged to rest well and try to exercise a little when they can.
Some patients complain of sore skin in the area being treated. The skin may look reddened or darker than usual. It may also get dry and itchy. Breakouts and blisters may also form around the treated skin area. Our teams will advise you on the best way of coping with this.
One side effect that most patients are concern of is hair fall. Some patients may experience hair fall out in the treatment area. Hair in other parts of the body is not affected. The hair should begin to grow back again a few weeks after the treatment ends.
Radiation to the mouth or throat, or parts of the digestive system (like the stomach or intestines) may cause eating and digestion problems. For instance, you may have sores in your mouth or throat, nausea, vomiting, or loss of appetite.
However, patients are encouraged to eat proteins and some high-calorie foods during this time to help the body recover. Experts have found that patients who eat well can better handle cancer treatment and side effects.