• Question: How does radiotherapy help in curing or slowing down cancer?

    Asked by anon-267460 to Iain on 14 Nov 2020.
    • Photo: Iain Tullis

      Iain Tullis answered on 14 Nov 2020: last edited 14 Nov 2020 12:30 am

      Radiotherapy works by damaging the DNA of cells in the volume that’s being treated.

      Ideally only cancerous cells would be exposed to the radiation but that’s not entirely possible as the oncologist prescribing the treatment doesn’t usually want to leave any cancer behind. The tumour is often not on the skin surface and there will be some overlaying non-cancerous tissue. To minimise the damage to the DNA of normal cells, the course of radiotherapy can be arranged such that the tumour is targeted from a variety of angles. This means that a large number of cells of normal tissue are exposed to a lower dose of radiation than the tumour. These normal cells are able to repair the damage to their DNA and most survive the low radiation dose. The cancer cells are not able to repair themselves after radiotherapy and they have been given a higher dose of radiation.

      Normal cells can also be damaged by radiotherapy, which may cause side effects.

      I’m not an oncologist – I’m an engineer building instruments to deliver radiation to cancers and to measure the properties of tissue that indicate where the cancer is.

      You could ask this question in one of the biology zones.

      https://www.cancerresearchuk.org/about-cancer/cancer-in-general/treatment/radiotherapy/about

Comments

  • Photo: Andreas

    Andreas commented on :

    Different types of radiation can help to improve how patients are treated.
    The hard part is to mainly reach cancer cells and leave healthy parts of the body alone as radiation can be harmful to sensitive organs. That’s why protons, the same particles running around the Large Hadron Collider, are often used for cancers deep in the body. Protons do most damage when they slow down. Think of catching a ball vs a just a glancing blow. By adjusting the energy or speed of the particles we can adjust how deep they penetrate and hence ensure that they do most damage where the cancer is.