Breast-cancer patients can learn how to hold their breath for more than five minutes in order to receive radiation therapy while motionless, which can lead to shorter treatments, lower overall doses, better tumor targeting and less destruction of healthy tissue.
A report in the current British Journal of Radiology describes the small study behind the successful demonstration.
Michael Parkes, MA, DPhil, of the University of Birmingham, England, and colleagues state that they previously developed techniques for healthy people to hold their breath for seven minutes.
In their current work, they trained 15 breast-cancer patients spanning the ages of 37 and 74 to pre-oxygenate, inhale and remain breathless under simulated radiotherapy treatment conditions.
The only mechanical intervention was a ventilator, which was used to induce hyperventilation and in the process reduce carbon dioxide levels in the bloodstream.
All the patients were non-smokers who were already undergoing radiotherapy and had no respiratory problems or previous training in breath-holding.
Before the training, which covered aspects such as relaxed posture and proper inhalation, the cohort’s average breath-hold was just 42 seconds.
After training, the average breath-hold duration was 5.3 minutes. One 52-year-old achieved an astonishing hold of 6.6 minutes.
The authors note that the typical beam-on time in breast radiotherapy is approximately two minutes.
At breakpoint, when the women resumed breathing as normal, all patients had normal concentrations of oxygen and carbon dioxide in their arterial blood.
Mean blood pressure had risen significantly in most, but it normalized within approximately 20 seconds of the breakpoint.
In the period immediately following the breath-hold, no patient was distressed, and none had gasping, dizziness or disturbed breathing.
Most crucially, during the breath-holding period, the mean movement of the tumor marker was less than 2 millimeters per minute.
In their discussion, Parkes et al. write that, despite the small sample, their technique deserves consideration beyond breast-cancer radiotherapy.
“While our pilot study focused on patients with breast cancer, the results will be representative of all patients with normal lung function,” they write. “Our approach could therefore be of benefit to patients with tumors in a wide range of thoracic and abdominal locations including the lung, esophagus, liver, pancreas, stomach and kidney.”
Management of respiratory-related motion at all these anatomic sites “is the subject of urgent ongoing research and technical modifications,” they add. “Our pilot data indicate that our novel approach should be brought into this debate.”
BJR has posted the full paper online.