Radiation Oncology

Radiation Oncology

One of the most important cancer treatment modalities is radiation oncology, also known as radiotherapy. This treatment modality employs the careful application of powerful radiation beams to either kill cancer cells or alleviate cancer-related symptoms.

How Radiation Therapy Works on Cancer

Radiation therapy, in high doses, kills cancer cells or slows their growth by damaging their DNA. Cancer cells that have had their DNA damaged beyond repair either stop dividing or die. When damaged cells die, the body breaks them down and removes them.

Radiation therapy does not immediately kill cancer cells. It can take days or weeks of treatment to damage DNA enough for cancer cells to die. The cancer cells then continue to die for weeks or months after the radiation therapy is finished.

Medical Oncology

Types of Radiation therapy

Radiation therapy is classified into two types: external beam and internal beam.

The type of radiation therapy you receive is determined by a variety of factors, including:

  • Type of cancer
  • The tumor's size, its location in the body, and how close the tumour is to normal tissues that are sensitive to radiation
  • your overall health and medical background
  • Whether you will receive additional cancer treatment
  • Other factors, such as your age and medical history

Radiation therapy using an external beam

External beam radiation therapy is delivered by a machine that directs radiation towards your cancer. The machine is large and potentially noisy. It does not touch you, but it can move around you, sending radiation to various parts of your body.

External beam radiation therapy is a local treatment, meaning it only affects one part of your body. For example, if you have lung cancer, you will only receive radiation to your chest, not your entire body.

Internal radiation treatment

Internal radiation therapy is a treatment in which a radiation source is implanted within your body. Radiation sources can be either solid or liquid.

Brachytherapy refers to internal radiation therapy using a solid source. This type of treatment involves implanting seeds, ribbons, or capsules containing a radiation source in or near the tumour. Brachytherapy, like external beam radiation therapy, is a local treatment that only targets a specific area of your body.

The radiation source in your body will emit radiation for a short period of time during brachytherapy.

Systemic therapy refers to internal radiation therapy using a liquid source. The term "systemic" refers to how the treatment travels through your bloodstream to tissues throughout your body, seeking out and killing cancer cells. Systemic radiation therapy is administered orally, intravenously via an IV line, or intramuscularly via injection.

Systemic radiation causes your body fluids, such as urine, sweat, and saliva, to emit radiation for a short period of time.

Cancer types that are treated with radiation therapy

Many types of cancer are treated with external beam radiation therapy.

Brachytherapy is most commonly used to treat head and neck cancer, breast cancer, cervix cancer, prostate cancer, and eye cancer.

To treat certain types of thyroid cancer, a systemic radiation therapy known as radioactive iodine, or I-131, is commonly used.

Targeted radionuclide therapy is another type of systemic radiation therapy used to treat some patients with advanced prostate cancer or gastroenteropancreatic neuroendocrine tumour (GEP-NET). This type of treatment is also known as molecular radiotherapy.Systemic therapy refers to external radiation therapy with a liquid source.

Targeted radionuclide therapy is another type of systemic radiation therapy used to treat some patients with advanced prostate cancer or gastroenteropancreatic neuroendocrine tumour. This type of treatment is also known as molecular radiotherapy.