Radiotherapy: How it works and possible side effects explained

Radiotherapy is one of the three main pillars of modern cancer treatment, alongside chemotherapy and surgical removal of tumours. Ionising radiation is used to target tumour tissue in order to destroy cancer cells or control their growth.

Radiotherapy uses high-energy ionising radiation to cause damage to the DNA of cells. Whilst healthy cells are able to repair such damage, cancer cells largely lack this ability. This makes them particularly sensitive to radiation.

Radiotherapy focuses on what is known as the target volume, i.e. the tumour and any adjacent tissue that may be affected. Modern radiotherapy techniques minimise the impact on surrounding healthy tissue and protect radiation-sensitive organs (organs at risk). This is achieved through precise treatment planning, which keeps the target volume as small as possible without compromising efficacy.

To minimise side effects, the total dose is divided into several smaller units, known as fractions. This fractionation allows healthy tissue to regenerate between sessions, whilst cancer cells continue to be damaged.

Radiotherapy is usually carried out over several weeks, with treatment five days a week. At the weekends, the body is given a break to recover.

Although modern radiotherapy is very well tolerated thanks to advanced technology, side effects may occur. These are usually temporary and are generally limited to the tissue being treated.

• Skin irritation: Redness, itching or hyperpigmentation of the skin may occur in the treated area. These symptoms usually subside completely after treatment.

• Tissue changes: Occasionally, tissue hardening may occur due to increased formation of connective tissue; this may not become apparent until months or years after treatment.

• Fatigue: Many patients report feeling exhausted during treatment, although this subsides once the course of therapy is complete.

In very rare cases, a second cancer may develop decades after radiotherapy. However, this is the exception and usually only occurs following particularly high doses of radiation. (The time lag before onset is typically 25–30 years after radiotherapy).

As well as in cancer treatment, radiation is also used in lower doses to treat benign conditions such as inflammation (e.g. osteoarthritis or tennis elbow). As the radiation dose is low, side effects do not usually occur in these cases.

A comprehensive risk-benefit assessment is carried out before every course of radiotherapy. Modern imaging and planning technologies ensure that the radiation dose is precisely targeted at the tumour. This enables us to guarantee effective treatment whilst minimising the risk of adverse effects.

Radiotherapy is a tried-and-tested method for treating cancer and is also suitable for certain non-cancerous conditions. Thanks to a combination of precise planning and state-of-the-art technology, treatments are now more effective and better tolerated than ever before.

If you have any questions about radiotherapy or would like to find out more about the options available at our practice, our experts will be happy to help. Book a consultation today and start planning your personalised treatment programme!