Researchers at the University of Birmingham working with clinical teams at University Hospitals Birmingham NHS Foundation Trust have successfully shown for the first time that breast cancer patients can be trained to achieve single prolonged breath holds of over five minutes, opening the door for targeted radiotherapy to be administered with just one dose in each daily session.
A typical radiotherapy beam in each daily session takes two minutes to deliver, with shaped radiation beams directed from several angles to intersect at the cancerous tumour. Because patients are not able to hold their breath for this long, most radiotherapy treatment is delivered while still breathing, and the ventilatory motion of the chest increases the risk of damage to nearby healthy tissue.
Clinical practice for some breast cancer patients is due to change with the introduction of repeated breath holds of around 20 seconds, to provide a stable target for the treatment, given over a number of doses in each session.
But the Birmingham team have demonstrated that the treatment in each session could now be delivered to patients in a single breath-hold.
The research “Safely prolonging single breath-holds to >5 minutes in cancer patients; feasibility and applications for radiotherapy“ published today in the British Journal of Radiology, builds on previous studies of healthy volunteers who were able to reach mean breath holds of seven minutes.
Dr Mike Parkes, from the University of Birmingham, explained, “The physiology of breath holding is well understood on the whole, but has been somewhat overlooked in medical research because until now it hadn’t any obvious clinical application”
“Following on from our preliminary work on healthy subjects, we wanted to see if we could help patients with breast cancer to achieve a breath hold of over two minutes to allow a radiotherapy treatment to be delivered in a single breath-hold.”
15 patients who were undergoing radiotherapy were recruited to the trial and trained to extend their breath holds safely. Patients are trained on how to maintain a relaxed posture, to practice inhaling and exhaling to maximum effect and then to assist them naturally to raise their blood oxygen levels and reduce their blood carbon dioxide levels, by preoxygenation and mechanically induced hypocapnia.
The average breath hold of patients after the training was 5.3 minutes, significantly more than the required target of 2 minutes.
Dr Parkes continued, “Being able to hit the cancerous tumour accurately is essential to avoid damage to other areas, including the heart muscle. Having a stable chest that we can target in one dose could be invaluable in protecting the surrounding tissue.”
“Although 5 minute breath-holds may seem astonishing to people, it is perfectly natural and safe for patients. Actually, anyone can do it. Patients are carefully monitored throughout the process and if their oxygen levels drop or their blood pressure rises above a certain level we would step in. The safety levels we use are very conservative so there is no risk attached.”
Of all 15 patients undergoing radiotherapy, 13 also had chemotherapy and 2 were taking Herceptin.
The Birmingham team believe that being able to assist patients in achieving a single breath-hold could greatly improve the long term survival and quality of life of breast cancer patients.
The study was supported by the NIHR/Wellcome Trust Birmingham Clinical Research Facility.
The trial was funded by the Queen Elizabeth Hospital Birmingham Charity as part of the Charity’s ongoing multi-million pound support of patients at the hospital.
For interview requests, a copy of the full paper or for more information, please contact Luke Harrison, Media Relations Manager, University of Birmingham on +44 (0)121 414 5134.
For out of hours media enquiries, please call: +44 (0) 7789 921 165
The National Institute for Health Research (NIHR) is funded by the Department of Health to improve the health and wealth of the nation through research. The NIHR is the research arm of the NHS. Since its establishment in April 2006, the NIHR has transformed research in the NHS. It has increased the volume of applied health research for the benefit of patients and the public, driven faster translation of basic science discoveries into tangible benefits for patients and the economy, and developed and supported the people who conduct and contribute to applied health research. The NIHR plays a key role in the Government’s strategy for economic growth, attracting investment by the life-sciences industries through its world-class infrastructure for health research. Together, the NIHR people, programmes, centres of excellence and systems represent the most integrated health research system in the world.