Side effects

Radiotherapy is a localised treatment that acts exclusively on a pre-defined part of the body. This distinguishes it from chemotherapy, which has a different (‘systemic’) mode of action, acting – and producing side effects – throughout the human body.

Due to the local nature of proton therapy, radiotherapy side effects usually only occur in the irradiated area of the body and manifest themselves in forms which may include:

• Irritation of the irradiated skin (radiodermatitis) and of mucous membranes (radiogenic mucositis)
• Burning sensation when urinating (following radiotherapy of the prostate)
• Hair loss (following radiotherapy in and around the head)

In rare instances nausea and vomiting These localised and acute proton therapy side effects are usually of a temporary nature and generally disappear within a few weeks of treatment.

Other side effects of proton therapy and potential late complications

Proton therapy is extremely precise, so that side effects can be minimised as far as possible. That said, side effects can occur. In addition to the localised acute side effects mentioned above, side effects affecting the patient’s well-being and certain late complications can result.

Tiredness, listlessness and loss of appetite

During proton therapy, patients may sometimes experience tiredness, listlessness or loss of appetite. This is caused by the effort your body puts into processing the rays. It can also manifest itself in fatigue, a broad term comprising various symptoms of exhaustion.

However, these side effects of proton therapy vary widely from individual to individual and depend on the part of the body being treated, on the individual or total dose and on the frequency of radiotherapy treatment. Added to this is the fact that sensitivity to radiation varies from person to person.

Late complications of proton therapy

In some cases, proton therapy can lead to late complications such as permanent scarring. In children in particular, radiotherapy can affect body growth and pubertal development, hormone production, salivation and the functions of the nervous system, eyes or ears. However, due to the pinpoint accuracy of proton therapy, such late complications are fairly rare. However, sometimes the location of a tumour is so difficult that not all organs or nerves can be spared. It is then necessary to weigh up which side effects will be the least restrictive.

Long-term observations concerning the side effects of proton therapy

Since patient treatment began at WPE, we have documented the treatments and any side effects that have occurred in anonymised form as part of studies. This data is intended help to draw nuanced conclusions on future possibilities offered by proton therapy, and also on tolerability and potential late complications.

Based on the results to date, for example, it can be said that proton therapy is well tolerated, partly due to the fact that surrounding healthy tissue is spared during proton irradiation.

With our research, we are constantly improving proton therapy and helping ensure that the side effects of radiotherapy can be avoided as far as possible in future.