News | Image Guided Radiation Therapy (IGRT) | June 07, 2022

A new precision radiotherapy technique described as ‘practice changing’ has been shown to reduce long-term side effects, including swallowing problems, for patients with head and neck cancer following treatment

A new precision radiotherapy technique described as ‘practice changing’ has been shown to reduce long-term side effects, including swallowing problems, for patients with head and neck cancer following treatment

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June 7, 2022 — Two-year results from the Dysphagia-Aspiration Related Structures (DARS) trial, which is funded by Cancer Research UK and the National Institute for Health and Care Research, were presented at the American Society for Clinical Oncology (ASCO) Annual Meeting. The study reveals that patients experienced less adverse side effects if they were treated with dysphagia-optimized intensity modulated radiotherapy (DO-IMRT), compared with standard IMRT.

IMRT is more precise than traditional forms of radiotherapy. It works by changing the shape of a radiation beam, so it is sculpted to closely fit a patient's tumor, reducing the amount of radiation affecting healthy tissue.

However, DO-IMRT, which has been pioneered by researchers from The Royal Marsden and The Institute of Cancer Research, London, is optimized to reduce the risk of swallowing difficulties, known as dysphagia. It does this by reducing radiation to the pharyngeal muscles, which support swallowing.

The randomised phase III study found double the number of patients treated with DO-IMRT (40%) reported being able to swallow as well as ever compared with those treated with standard IMRT (20%) two years following treatment. Patients who received DO-IMRT had also previously reported better swallowing function at 12 months compared those who received standard IMRT.

Of those treated with DO-IMRT, over four in five (81%) reported high normalcy of diet - meaning they were still able to eat at least some foods that require chewing - and over nine in 10 (92%) said they felt comfortable eating in public, compared with just under 73% and 85% of those treated with standard IMRT respectively. 

The study included 112 newly diagnosed patients with oropharyngeal and hypopharyngeal cancers (tumours of the throat) from centres across the UK and Ireland. Half received standard IMRT and half received DO-IMRT every day for six weeks.

There was no evidence of a difference in survival rates between the two approaches.

Around 12,400 people are diagnosed with head and neck cancer in the UK each year1 and about 70% are left with life changing side effects including swallowing problems, making it difficult to eat and drink, after radiotherapy.

The DARS trial was coordinated by the Clinical Trials and Statistics Unit at The Institute of Cancer Research, London and was supported by strong collaborations between participating centres and a multidisciplinary team of doctors, speech and language therapists (SLT), radiographers, research nurses and physicists.

Michael Brown2, 73, was diagnosed with upper oesophageal cancer in September 2017 after experiencing recurrent mild pain in his throat and ear. He was referred to The Royal Marsden where he was recruited to the DARS trial and, six months after finishing the treatment, he was able to eat almost normally. He said:

“When I was told about the study, I agreed to join immediately. Although it was randomized and I didn’t know if I’d be getting the new treatment, I just wanted to do everything possible to ensure I had a good quality of life afterwards.

“I received the treatment every day for six weeks and, while it wasn’t pleasant, the team caring for me were really supportive. After just six months, I was back to eating almost normally, though certain foods (e.g. spicy and acidic foods) were problematic for longer. I now love going out for meals and I have a big garden where I grow my own fruit and vegetables so being able to retain my ability to swallow was hugely important. It would be wonderful if more patients could access this more targeted form of radiotherapy.

“I am really grateful to the team of doctors, dietitians, nurses, therapeutic radiographers, and speech and language therapists that helped me get back to normal life.”

Professor Chris Nutting, Consultant Clinical Oncologist at The Royal Marsden NHS Foundation Trust and Professor of Radiation Oncology at The Institute of Cancer Research, London, said:

“This practice-changing study represents a major step forward for treating head and neck cancer patients. We’ve shown that this optimised IMRT treatment can spare patients’ swallowing muscles and, crucially, without lessening the success of their treatment.

“This new technique, which can have a major impact on patient’s quality of life, is achievable for all centres currently offering IMRT. It simply requires some additional time from the radiation oncologist and physicist to make adjustments to help reduce the irradiation of the muscles that control swallowing. Next, we’re planning to teach others around the world how to reproduce this new treatment approach.”

Dr Justin Roe, Consultant SLT and Joint Head of the Department of Speech, Voice and Swallowing at The Royal Marsden NHS Foundation Trust, said: “Eating and drinking are not only key for survival but are also two of the most fundamental pleasures in our lives and are often central to the way we socialise. However, despite advances in recent years, radiotherapy can be devastating for patients with head and neck cancer, and, in most cases, swallowing is affected.

“The treatment sometimes leaves people unable to eat and drink safely or comfortably. This can cause enormous distress during mealtimes. Patients may also avoid social situations involving food and drink too, leading to isolation. It can also have a significant impact on hydration, nutrition and in the most severe cases, can lead to significant respiratory complications. I’m delighted the DARS trial has discovered a new kinder way to treat this patient group, offering many a significantly improved chance of getting back to a more normal life.”

Martin Ledwick, Cancer Research UK’s head nurse, said: "Behind the results of each clinical trial, there are real people who deserve the best possible quality of life. It’s important the interventions not only work, but can be kinder so they are still able to enjoy life’s pleasures. 

“It’s difficult for many of us to imagine not being able to swallow properly, but this can be the reality for head and neck cancer patients post-treatment. 

“These promising results could make life after treatment brighter for head and neck cancer patients, and we look forward to seeing this kinder form of radiotherapy make its way to the clinic.” 

Professor Emma Hall, Deputy Director of the Clinical Trials and Statistics Unit at The Institute of Cancer Research, London, said: “Radiation is a vital treatment for patients with head and neck cancer but it can damage important muscles involved in swallowing and talking. This cutting-edge radiotherapy technique delivers more precise radiotherapy – targeting cancer cells while sparing these important structures. I am very pleased that the latest results of the DARS trial show the potential of DO-IMRT to reduce side effects from radiotherapy and improve patient’s lives.”

The DARS trial has been funded by Cancer Research UK with support from The National Institute for Health and Care Research and The Royal Marsden Cancer Charity.

For more information:



  1. Cancer Research UK:
  2. Not the patient’s real name.  

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