How to reduce the harm of radiotherapy

Protect sensitive organs from radiation to reduce the side effects of radiation therapy

Lina Medvedeva, XX2 century

A new way of planning radiation therapy can prevent damage to sensitive organs around tumors, which will reduce side effects. The technique was developed by physicists at the Institute of Cancer Research, London, and the Royal Marsden Hospital, a partner London oncology clinic, and requires the use of a complex mathematical formula to reduce radiation damage to sensitive organs.

Despite the fact that radiation therapy is used to treat various types of cancer, side effects can occur several months or even years after treatment and significantly affect the patient's quality of life.

Radiation therapy should direct as large a dose of radiation as possible to cancer cells in order to kill the cancer, but not to hurt healthy tissue. Doctors plan treatment carefully, based on the patient's tomogram, irradiating the area around the tumor to make sure that the tumor is all affected by the radiation beam. However, current planning techniques do not take into account the presence of organs in the beam path.

With a disease such as prostate cancer, the organs closest to the tumor – such as the intestine and rectum – are especially sensitive to radiation. Therefore, the development of radiotherapy plans that would avoid them, but still treat the entire tumor, can lead to fewer side effects and better treatment in general.

The new technique, the details of which are published in the journal Physics in Medicine & Biology (Tsang et al., Novel adaptive beam-dependent margins for additional OAR sparing), uses the concept of "adaptive edges" and takes into account nearby organs when planning the treatment area.

For the study, each radiation beam was mapped to measure the total irradiation of the tissues around the tumors. Then the position of the sensitive organs was taken into account in order to adjust the edges of the radiation therapy application area.

Researchers from the Institute of Cancer Research tested the system using data from five prostate cancer patients, creating radiation therapy plans that took into account the position of the bladder and rectum. They found out that their plans delivered radiation doses to the tumor, and the surrounding organs were exposed to less radiation than if the refinements had not been made.

The lead researcher, Professor Uwe Oelfke, says: "Radiation therapy is very effective in cancer, but the harmful effects of radiation on healthy tissues can lead to the fact that we will face side effects that can affect the quality of life of the patient. Working with the edges is necessary to ensure complete treatment of the tumor, and safely reducing these edges is the key to further improving the end result for the patient."

Henry Tsang, one of the authors of the article, adds: "Our study is devoted to the adaptation of the edges, this is important, since nearby organs are less susceptible to radiation, while the impact on the tumor continues. We have proposed a technique for planning prostate cancer treatment, but it is easy to adapt it to other forms of the disease."

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