KEY POINTS
- The prospective observational study included 36 participants, comprising 20 healthy volunteers and 16 women with breast cancer. Each participant completed four sessions and 12 prolonged DIBHs, generating 432 breath-holds, half performed with a cognitive exercise.
- Before each prolonged breath-hold, participants hyperventilated for 3 minutes at 16 breaths/minute while receiving humidified 60% oxygen at 40 L/min through high-flow nasal oxygen. Breath-holds were performed prone on an open-access breast couch.
- Cognitive engagement consisted of viewing changing colored shapes on a tablet and silently counting a specified shape during the breath-hold. In mixed-model analysis, this task prolonged L-DIBH by 14.9 seconds overall and by 19.0 seconds in breast cancer patients, with both differences statistically significant.
- A substantial learning effect was also observed. Each successive session added approximately 8.7 seconds overall, while the second and third breath-holds within a session were approximately 24.4 and 41.2 seconds longer than the first.
- Median unsupported baseline DIBH duration was 43 seconds overall and 39 seconds in patients. During the prolonged protocol, median L-DIBH duration increased to 138 seconds overall and 114 seconds in the breast cancer subgroup.
- The cognitive task improved breath-hold duration in participants with both shorter and longer baseline breath-hold capability. Among those with poorer baseline performance, the numerical benefit of the mental exercise exceeded the improvement associated with one additional training session.
- The intervention was well accepted: 64% preferred the mental exercise, and 98% of tasks were completed with perfect or good accuracy. Reported effects were mild, most commonly dry mouth or throat (19.4%), dizziness (16.7%), coughing (13.9%), and peripheral paraesthesia (13.9%).
- Clinical applicability remains uncertain. Testing occurred outside the treatment bunker without SGRT breath-hold monitoring, only 16 patients were included, and the visual task could compete with conventional visual DIBH feedback. The study did not test whether longer breath-holds reduced treatment interruptions, improved reproducibility, or lowered cardiac dose.
CLINICAL TAKEAWAY
A very simple cognitive task produced a measurable improvement in prolonged DIBH duration, particularly relevant for patients who struggle with breath-hold performance. The concept is inexpensive and appealing, but this remains proof-of-concept work using an oxygen and hyperventilation protocol rather than evidence that cognitive distraction improves routine breast radiotherapy delivery.