Home News & Events News BLOG: What is the Difference Between Radiotherapy and Chemotherapy?

Radiotherapy and chemotherapy are two different forms of cancer treatment that ultimately aim to achieve the same goal – to either reduce the size of cancerous tumours or to completely eradicate the cancer. The main difference is that one uses radiation while the other uses cytotoxic drugs to destroy cancer cells.

Combination therapy is used when two different forms of treatment complement each other. For example, where chemotherapy works through the whole body as the cytotoxic drugs are administered, radiotherapy is a more targeted approach. A treatment combination of both radiotherapy and chemotherapy can be referred to as chemoradiation. Quite often, it may be decided that the best course of action is to combine both radiotherapy and chemotherapy to treat cancer.

How Chemotherapy Works

Chemotherapy aims to destroy cancer cells in the body, preventing them from growing and dividing. In the United Kingdom, there are over 50 different chemotherapy drugs licensed for use that have been proven to help treat more than 200 different types of cancers. The exact drug (or drugs) used will be determined by the consultant who will consider factors such as the patient’s age, overall health, location and stage of cancer.

At the Rutherford, our clinical teams administer chemotherapy drugs in one of two ways which are:

  • Orally – via prescription tablets that can be taken at home.
  • Intravenously – via the use of a small needle inserted into the hand or arm that delivers the drug(s) directly into the bloodstream. This form of treatment takes place at a Rutherford Cancer Centre in one of our state-of-the-art infusion suites.
Blog what is difference between chemo and radio

As the chemotherapy drug(s) travels around the body’s bloodstream, the cancer cells will become compromised and die off. Chemotherapy may also damage healthy cells during the treatment, but these cells will repair themselves once the treatment is over, whereas cancer cells are unable to recover.

One course of chemotherapy will typically last anywhere between three and six months, with cycles administered around three to four weeks at a time, allowing time for the body to recover between each cycle. Patients receiving chemotherapy intravenously should expect one session to last at least a few hours and at maximum an entire day.

How Radiotherapy Works

Where chemotherapy works the entire body, radiotherapy differs by targeting isolated areas of the body by using high-energy x-rays, known as photons, which are delivered to cancer cells. This prohibits the cells’ ability to grow and replicate, which ultimately kills the cancer cells.

External beam radiotherapy (also referred to as conventional radiotherapy) is delivered using the latest technology for the highest accuracy and precision possible. A part of their treatment planning, patients undergo CT and MRI scans to pinpoint the size and location of the tumour before treatment, which will be administered over the course of several sessions, as the full dose of radiotherapy is split into several smaller doses. These doses may take place over a few days to a few weeks.

One of the key differences between radiotherapy and chemotherapy is the reduction of side effects that patients experience when undergoing a course of radiotherapy compared to chemotherapy. This is because the radiotherapy machines utilised at the Rutherford Cancer Centres are specifically designed to shape the x-rays to match the tumour and the area around it. Fewer healthy cells are damaged during radiotherapy compared to chemotherapy.

Radiotherapy techniques

There are three different techniques used when administering radiotherapy at the Rutherford Cancer Centres, allowing our team to be able to deliver the best treatment for our patients. These are:

  • Volumetric-Modulated Arc Therapy (VMAT) – using a LINAC machine that can rotate around the patient, the shape and intensity of the x-ray beam are adjusted accordingly, thus delivering less radiation to healthy skin cells. This is a type of Intensity Modulated Radiation Therapy (IMRT).
  • Image-Guided Radiotherapy (IGRT) – a variety of systems are used to precisely locate the cancer cells in the body using scans and x-rays. CT imaging is used to accurately deliver radiotherapy to the treatment area.
  • Deep Inspiration Breath-Hold (DIBH) – this technique is mostly used for patients receiving radiotherapy in areas of the body influenced by breathing motion (such as the lungs). Patients are asked to hold their breath whilst receiving treatment to reduce the amount of radiation delivered to healthy skin cells. Patients will be invited to a coaching session before using the DIBH technique during a treatment session.

What are the Side-Effects of Radiotherapy and Chemotherapy?

Side-Effects of Chemotherapy

Not all patients who receive chemotherapy will experience side effects, many of which can be treated with other symptom-managing treatments or therapies.

Some of the side-effects that chemotherapy patients report may include tiredness/fatigue, nausea, hair loss, anaemia, increased susceptibility to bruising and bleeding, sore/irritated mouth (mucositis), loss of appetite, skin and nail changes, concentration and memory problems, sleeping issues, reduced libido, diarrhoea and constipation and emotional issues.

Side-Effects of Radiotherapy

Although patients who undergo radiotherapy are likely to experience fewer side effects than those who undergo chemotherapy, some are to be expected. Many of these can be managed through other courses of treatments that the treatment team at the Rutherford Cancer Centres can advise on.

Some of the side-effects that radiotherapy patients report may include sore skin around the treated area, tiredness/fatigue, hair loss around the treated area, nausea, loss of appetite, sore mouth and/or discomfort when swallowing, diarrhoea, stiff joints and muscles around the treated area, reduced sex drive, emotional issues and lymphedema.

Why Would I Need Chemotherapy and Radiotherapy?

Radiotherapy is often combined with other forms of treatment, such as chemotherapy and surgery, to provide the best possible chance of a positive outcome. This may involve using radiotherapy as a means of reducing the size of the tumour before chemotherapy or utilising chemotherapy before using radiotherapy to clear the remaining cancer cells in an isolated area.


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For more information regarding chemotherapy and radiotherapy, as well as of the other treatments offered at the Rutherford Cancer Centres, please get in touch with us today.

why would I need radiotherapy or chemotherapy

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