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NCT Number: NCT07594691

Inhale and Exhale Breath Holds to Improve the Radiation Therapy Accuracy in People With Upper Abdominal Cancers

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).

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Key information

Conditions

Abdominal Cancer

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Princess Margaret Cancer Centre Toronto, Ontario

Toronto, Ontario, M5G 2M9, Canada

Location status: Recruiting

Location contact

Laura Dawson

PRINCIPAL_INVESTIGATOR

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

Simulation and treatment imaging

Diagnostic Test

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.

Primary outcomes

  1. Total dose to radiation targets and OARs

    Time frame: 12 Months

    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

Secondary outcomes

  1. Positional change between a deep inhale and deep exhale breath hold

    Time frame: 12 Months

    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

Study contacts

Contact information is provided by the study sponsor or research team.

Laura Dawson, MD FRCPSC FASTRO FCAHS

CONTACT

[email protected]

416-946-4501 ext. 3276

Sponsors and collaborators

Lead sponsor

University Health Network, Toronto

Other

Registry information

Official study title

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

Acronym: INEX-RT P

Important dates

Study start
2026
Primary completion
2027
Study completion
2028
First posted
May 19, 2026
Registry last updated
May 29, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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