Inhale and Exhale Breath Holds to Improve the Radiation Therapy Accuracy in People With Upper Abdominal Cancers (INEX-RT P)

Inhale and Exhale Breath Holds to Improve the Therapeutic Ratio in Upper Abdominal Cancers Treated With SBRT

This is a prospective quality improvement study. The INEX RT P study will prospectively evaluate INEX RT R that optimizes radiation dose delivery to the target while minimizing dose to critical organs at risk (OAR) by treating patients with different phases of breath hold (inhale and exhale) during the same course of SBRT. 15 patients with abdominal cancer whom are expected to achieve a dosimetric advantage from this technique due to OAR proximity to target will be treated using INEX RT. Investigators hypothesize increasing the dose to the RT target by at least 10% while simultaneously decreasing or maintaining dose to adjacent critical OARs when using a combination of breath hold positions to purposefully vary the position of OARs during different fractions of the same treatment course, when compared to RT treatments planned on a single breath hold phase alone (present standard of care).

Study Overview

• Status: Recruiting
• Conditions: Abdominal Cancer
• Intervention / Treatment: Diagnostic test: Simulation and treatment imaging

• Study Type: Interventional
• Enrollment (Estimated): 15
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Laura Dawson, MD FRCPSC FASTRO FCAHS; Phone Number: 3276 416-946-4501; Email: Laura.Dawson@uhn.ca

Study Locations

• Canada
  • Ontario
    • Toronto, Ontario, Canada, M5G 2M9
      • Recruiting
      • Princess Margaret Cancer Centre Toronto, Ontario
      • Principal Investigator: Laura Dawson

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Age ≥ 18
• Any patient undergoing radiation therapy for a cancer lesion in the abdomen in close proximity to OARs that is hypothesized to have differential displacement on inhale and exhale breath hold CT scans of the OAR relative to the tumor.
• Patients need at least 3 fractions of RT
• Critical OARs are within 2 cm of luminal GI structures, chest wall, or previous radiation fields
• Able to receive and understand verbal and written information regarding study and able to give written informed consent

Exclusion Criteria:

• Inability to perform inhale or exhale breath holds during standard workflow CT simulation evaluation

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: Imaging

Diagnostic test: Simulation and treatment imaging; Obtain inhale and exhale breath hold images planned to split radiation delivery between inhale and exhale breath hold phases. For radiotherapy courses with an odd number of fractions, the phase of breath hold with higher reproducibility or anatomic advantage will be used for the additional fraction of radiotherapy. If during the treatment planning the investigators determine that the patients will benefit from the multiple breath holds technique, the patients will be treated using the composite breath hold plan. Additional one or two cone beam CTs will be obtained on treatment days for all patients using the inhale and exhale breath hold technique.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Total dose to radiation targets and OARs	Total dose to radiation targets and OARs on standard workflow (FB ITV or exhale/inhale single breath hold phase only) compared to INEX RT. Unit: Gy	12 Months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Positional change between a deep inhale and deep exhale breath hold	Evaluate the motion of critical OARs during inhale and exhale breath holding techniques during simulation and during daily treatments, including the magnitude of positional change between a deep inhale and deep exhale breath hold. Unit: mm	12 Months

Collaborators and Investigators

• Sponsor: University Health Network, Toronto

Study record dates

Study Major Dates

• Study Start (Actual): May 25, 2026
• Primary Completion (Estimated): May 30, 2027
• Study Completion (Estimated): January 30, 2028

Study Registration Dates

• First Submitted: May 13, 2026
• First Submitted That Met QC Criteria: May 13, 2026
• First Posted (Actual): May 19, 2026

Study Record Updates

• Last Update Posted (Actual): May 29, 2026
• Last Update Submitted That Met QC Criteria: May 26, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: SBRT; Breath; INEX RT; Breath Hold Immobilization
• Other Study ID Numbers: 26-5095

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No