How is radiation therapy used to treat throat cancer?
Radiotherapy or radiation treatment is the most popular treatment modality for throat cancer. In this form of treatment, high energy radiation beams are directed at a tumour, with the aim of destroying the tumour completely or shrinking the tumour. Radiation treatments have been in use for more than 100 years in medical treatments (most commonly as X-rays), and they are extremely effective in treating solid tumours such as the ones present in hypopharyngeal and oropharyngeal throat cancer.
The following types of radiation treatments are available in the treatment of throat cancer
External beam radiation therapy (EBRT)
This is the most commonly used radiation format used in the treatment of hypopharyngeal cancers. In EBRT, an external radiation source (such as a high energy X-ray) is focused on the exact site of a tumour, to kill it completely or to shrink the size of a tumour.
Brachytherapy
This is a form of internal radiation therapy. In this process, a small amount of radioactive material is inserted near to the tumour site, or within the tumour site. Brachytherapy is used for the treatment of oropharyngeal cancer and less common in the treatment of hypopharyngeal cancer. It can be used as an individual therapy or in combination with external beam radiation therapy.
Image-guided radiotherapy (IGRT)
IGRT is a type of technique used in EBRT, which uses a variety of imaging techniques such as X-rays or CT scans, alongside regular (external beam) radiotherapy. The addition of imaging assistance allows doctors to confirm the exact location of a tumour as it starts shrinking so that the radiation treatment can become progressively more targeted.
Intensity modulated radiotherapy (IMRT)
In IMRT, radiation oncologists use linear accelerators to deliver an extremely precise dosage of radiation, which is designed to attack the specific size of a tumour. For throat cancer, it is an important treatment modality because it provides control over the amount of radiation that the throat and chest area are exposed to.
Volumetric modulated arc therapy (VMAT)
VMAT is an extremely new form of radiotherapy that was first performed in the UK. Using 3D volumetric imaging systems, VMAT maximizes the intensity (dose) of radiation at the exact tumour site, while simultaneously minimizing the radiation exposure to healthy tissue areas. Due to the targeted nature of such radiation, the overall treatment timelines are also greatly reduced in VMAT.
