Breath-holding times in various phases of respiration and effect of respiratory training in lung cancer patients

Introduction: Breath-holding (BH) technique is used for reducing the intrafraction-tumour motion in mobile lung tumours treated with radiotherapy (RT). There is paucity of literature evaluating differences in BH times in various phases of respiration in patients with lung cancer.

Methods: One hundred consecutive patients with lung cancer planned for radical RT/chemoradiation were accrued in the study. Eighty-seven patients were eligible for analysis at RT conclusion. Baseline pulmonary function test (PFT) were performed in all patients, and respiratory training was given from the day of RT planning. Deep inspiration breath hold (DIBH), deep expiration breath hold (DEBH) and mid-ventilation breath hold (MVBH) were recorded manually with a stopwatch for each patient at four time points (RT planning/baseline, RT starting, during RT and RT conclusion).

Results: Median DIBH times at RT planning, RT starting, during RT and RT conclusion were 21.2, 20.6, 20.1 and 21.1 s, respectively. The corresponding median DEBH and MVBH times were 16.3, 18.2, 18.3, 18.5 s and 19.9, 20.5, 21.3, 22.1 s, respectively. Respiratory training increased MVBH time at RT conclusion compared to baseline, which was statistically significant (19.9-22.1 s, P = 0.002). DIBH or DEBH times were stable at various time points with neither a significant improvement nor decline. Among various patient and tumour factors Forced Vital Capacity pre-bronchodilation (FVCpre ) was the only factor that consistently predicted DIBH, DEBH and MVBH at all four time points with P value <0.05.

Conclusions: BH was well tolerated by most lung cancer patients with minimum median BH time of at least 16 s in any of the three phases of respiration. Respiratory training improved MVBH time while consistently maintaining DIBH and DEBH times throughout the course of radiotherapy.