A prospective trial demonstrating the benefit of personalized selection of breath-hold technique for upper-abdominal radiotherapy using the Active Breathing Co-ordinator (ABC).

Abstract

For upper abdominal (UA) tumors, our institutional-standard motion reduction method is Expiration Breath Hold (EBH), using Active Breathing Coordinator (ABC)TM. However, an individual patient's breath-hold (BH) reproducibility (RBH) may be improved in Deep Inspiration or Inspiration Breath-Hold (DIBH or IBH). This trial compared the tumor position RBH, stability (SBH), and breath-hold time (TBH) of three BH methods, using ABC, to personalize the selection of technique, by employing a pre-planning screening assessment. Patients planned for UA radiotherapy (kidney, pancreas, liver, or adrenal gland), were invited to participate in this prospective trial. Active Breathing Coordinator (ABC)TM education was conducted, then participants attempted EBH, DIBH and IBH, in randomized order. During five consecutive BH's for each method, kV fluoroscopy images of the diaphragm were acquired. The BH technique selection was personalized according to a decision matrix. The EBH and the personalized technique cohort mean RBH and SBH of were analyzed. Between May 2019 and March 2020, 19 participants were recruited. Median age of participants was 68 years (range 32-81). Tumor sites included kidney (n=1), adrenal gland (n=5) and liver (n=14). One participant was excluded due to poor BH compliance, leaving 270 images from 18 participants for analysis. Mean TBH was 22.1, 23.9 & 24.2 seconds for EBH, DIBH and IBH respectively. Screening selected EBH for 44% (n=8), IBH for 39% (n=7) and DIBH for 17% (n=3) of participants. The mean RBH was superior at 0.92mm (0.79mm SD) for the personalized technique, compared to EBH of 1.79mm (1.49mm SD) (p=0.016). Pre-planned subset analysis of participants whose personalized technique was not EBH showed improved mean RBH of 0.63mm (0.29mm SD) compared to their EBH RBH of 2.2mm (1.7mm SD) (p=0.011). In 56% of participants, DIBH or IBH demonstrated superior RBH compared to EBH Personalized BH screening can inform selection of an ABC BH method which provides optimal RBH with improved TBH for an individual's planning and treatment course. Australian New Zealand Clinical Trials Registry (ANZCTR): XXX (withheld - blinded manuscript).