Treatments

Radiation treatment can be administered as a complete cure by itself, or in combination with surgery and/ or chemotherapy. Radiation can also be given as a palliation to prevent suffering and pain as end of life support in a malignant brain or spinal tumour.

Types of Radiation Therapy

External beam radiation is delivered through a machine outside the body, and Brachytherapy or internal beam radiation is done by placing radioactive material in the cancerous part of the body. Another type is Systemic radiation therapy where radioactive substances like radioactive iodine are used to kill cancer cells through the blood.

First, treatment planning is done by simulation. Detailed scans are taken to plot the cancer area precisely, including ultrasounds, CT scans, MRIs and PET scans. To ensure that the radiation is given in the same position each time, body molds, masks and other body frames are tailormade and temporary skin markings are done.

After this the precise dosage of the radiation, and the safest angles (to prevent harm to surrounding normal tissue) for delivery are calculated by a team of Radiation Oncologist, medical physicist and dosimetrists. Treatment is monitored constantly to ensure the positions and angles have not changed in anyway.

The type of radiation therapy to be selected depends on the type, size & location, depth of the cancer, how close it is to normal tissues, the age, general medical and nutritional status of the patient, and if other adjuvant therapy is necessary.

External Radiation Therapy

A linear accelerator or LINAC is routinely used to deliver external radiation in daily treatment sessions over the course of several weeks. The number of treatment sessions depends on many factors, including the total radiation dose that will be given.

Most common types of external-beam radiation therapy are administered through Image Guided Radiation Therapy (IGRT), Intensity Modulated Radiation Therapy (IMRT) and 3- Dimensional Conformal Radiotherapy (3D-CRT) machines that use very sophisticated computer software to deliver radiation to very precisely shaped target areas.

Stereotactic radiosurgery (SRS) delivers one or more high doses of radiation to a small tumour and is most commonly used in treating brain or spinal tumours and brain metastases from other cancer types. Stereotactic body radiation therapy (SBRT) or Cyberknife treats tumours that lie outside the brain and spinal cord that move with the normal motion of the body.

Internal radiation therapy

Brachytherapy is delivered by strategically placing radioactive pellets or wires inside or on the body. Different techniques are Interstitial (within a tumour), Intracavitary (within a surgical cavity or a body cavity), and Episcleral (to treat melanoma inside the eye). Delivery devices, such as needles and catheters, are used and as the isotopes decay naturally, they give off radiation that damages nearby cancer cells.

Permanent Brachytherapy is when the pellets are surgically placed within the body permanently, and in Temporary Brachytherapy, the delivery sources are removed after treatment.

Radiation therapy given before surgery is called pre-operative or neoadjuvant radiation and is used to shrink a tumour before being surgically removed. Radiation given during surgery is called Intraoperative radiation therapy (IORT), and when given after surgery is called post-operative or adjuvant radiation therapy. Chemoradiation is the combination of Chemotherapy and Radiation.

Side effects of Radiation Therapy

Acute side effects that occur during treatment include extreme tiredness, skin irritation or damage at regions exposed to the radiation beams, hair loss at radiation site, nausea/ vomiting, urinary and bowel issues if lower abdomen or bladder is radiated. These effects usually disappear when treatment stops.
Chronic effects of radiation are depends on the area treated like Fibrosis of the radiated part, damage to the bowels, causing diarrhoea and bleeding., memory loss, infertility, and secondary cancers.