Women can learn to hold their breath for long stretches during breast cancer radiation treatments, a technique that might help minimize damage to healthy tissue, according to a small study.
With instruction, women in the study managed to hold their breath for an average of 5.3 minutes.
"If the tumor stays still, then more surrounding tissue can be spared," said lead study author Dr. Michael Parkes of the University of Birmingham in the U.K.
"Radiotherapy is currently delivered with the chest deflated," Parkes added by email.
"If the radiotherapy is delivered with the chest inflated, the breast is moved further away from vital structures like the heart," Parkes continued. "Also, the lung is inflated, so it is less dense and therefore less vulnerable to damage."
To assess the feasibility of teaching women to hold their breath during radiation, Parkes and colleagues recruited 15 breast cancer patients already undergoing radiation.
The women ranged in age from 37 to 74 years old. None of them had respiratory, cardiovascular or neurological diseases, diabetes or obesity - all of which might make it more challenging for patients to master extended breath holds.
The women were also non-smokers, and they didn't have previous experience trying to hold their breath for long periods of time.
At the start of the study, the women could hold their breath for an average of 42 seconds, researchers report in the British Journal of Radiology, online May 11.
To prolong that time, women worked over several days on maintaining a relaxed posture and inhaling and exhaling more slowly during the study. They also wore face masks that let researchers detect how long the women stopped breathing.
After training, the longest breath hold was 6.6 minutes, achieved by a 52-year-old woman.
Risks of prolonged breath holding can include dizziness, elevated blood pressure and muscle cramping. Women in the study didn't experience serious side effects and their elevated blood pressure returned to normal within 20 seconds of breaking the breath hold.
Beyond its small size, the study is limited by its exclusion of women with a variety of health issues that can complicate breathing, the authors note. This means the results might not be similar for a broader population.
Even so, it makes sense to continue exploring breath holds because any efforts to reduce movement in the body during radiation can improve treatment, said Dr. Joshua Meyer, a researcher in radiation oncology at Fox Chase Cancer Center in Philadelphia.
"If we can make moving targets stationary by eliminating the motion caused by breathing, we can treat a smaller volume around the tumor, and thereby decrease the dose to healthy tissue and increase the safety of the treatments," Meyer, who wasn't involved in the study, said by email.
A particular concern with breast cancer radiation is the potential for heart complications to develop years later, and breath holds may help minimize this risk, said Dr. Daphna Gelblum, a radiation oncology researcher at Memorial Sloan Kettering Cancer Center Westchester, in West Harrison, New York.
"As breast cancer is commonly diagnosed early and women will live many years after treatment completion, the late complications of treatment are important to them," Gelblum, who wasn't involved in the study, said by email.
While the main goal of breath holds is to spare surrounding tissue, keeping tumors still with this technique may also allow some patients to receive larger radiation doses with the potential to improve survival odds in some diseases such as early-stage lung cancer, Gelblum said.
"Dose escalation has become feasible as we have gained a greater confidence in tumor location permitting us to shrink the size of our treatment windows and greatly reducing the normal tissue toxicity," Gelblum said.
SOURCE: http://bit.ly/1szgGBh
Br J Radiol 2016.
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