Hypofractionated Pencil-Beam Scanning Intensity-modulated Proton Therapy (IMPT) in Recurrent Rectal Cancer (IMPARC)

September 15, 2025 updated by: Washington University School of Medicine

Hypofractionated Pencil-Beam Scanning Intensity-modulated Proton Therapy (IMPT) in the Reirradiation of Locoregionally Recurrent Rectal Cancer - IMPARC

The purpose of this trial is to determine the maximum tolerated dose (MTD) of hypofractionated IMPT for the reirradiation of locoregionally recurrent rectal cancer.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Terminated

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
15

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.
  • Name: Allen Mo, M.D., Ph.D.
  • Phone Number: 314-362-7769
  • Email: amo@wustl.edu

Study Locations

  • United States
    • Missouri
      • St Louis, Missouri, United States, 63110
        • Washington University School of Medicine

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • History of biopsy-proven adenocarcinoma of the rectum, anus or rectosigmoid junction of any stage now with recurrent disease in the pelvis
  • One prior course of radiation therapy to the pelvis for rectal cancer
  • ECOG performance status 0-2
  • At least 18 years of age
  • Women of childbearing potential and men must agree to use adequate contraception (hormonal or barrier method of birth control, abstinence) prior to study entry and for the duration of study participation. Should a woman become pregnant or suspect she is pregnant while participating in this study, she must inform her treating physician immediately.
  • Able to understand and willing to sign an IRB-approved written informed consent document.

Exclusion Criteria:

  • Patients with pre-existing radiosensitizing conditions, such as connective tissue disorders (i.e. lupus, scleroderma) and genetic mutations (i.e. ataxia-telangiectasia)
  • A history of other malignancy with the exception of malignancies for which all treatment was completed at least 2 years before registration and the patient has no evidence of disease, basal cell or squamous cell carcinoma of the skin that were treated with local resection only, or carcinoma in situ of the cervix. Patients with history of prostate cancer treated without radiotherapy and no evidence of disease are eligible
  • More than one prior course of radiation to the pelvis for rectal cancer
  • Prior radiation to the pelvis for disease other than rectal cancer
  • Tumor in the rectum/colon requiring radiation therapy to the full circumference of the rectum/colon.
  • Current treatment with any investigational agents.
  • Uncontrolled intercurrent illness including, but not limited to, ongoing or active infection, or unstable angina pectoris
  • Pregnant and/or breastfeeding. Women of childbearing potential must have a negative urine or serum pregnancy test within 14 days of study entry.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Non-Randomized
  • Interventional Model: Sequential Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Dose Level 1: Hypofractionated Pencil-Beam Scanning Intensity-modulated Proton Therapy (IMPT)
  • Radiotherapy will consist of five fractions, delivered once daily, with pencil beam scanning proton beam therapy using the defined dose in dose level 1 (30 Gy).
  • The use of Intensity Modulated Radiation Therapy (IMRT) with photon beam therapy is permitted at the discretion of the treating investigator in order to avoid extended treatment delays due to logistical reasons (e.g. machine downtime).
Radiation: Hypofractionated Pencil-Beam Scanning Intensity-modulated Proton Therapy
When feasible it is strongly recommended that radiotherapy begin on a Monday
Other Names:
  • IMPT
Device: MEVION S250i Hyperscan and Adaptive Aperture Proton Therapy Machine
-The device that will administer the IMPT
Experimental: Dose Level 2: Hypofractionated Pencil-Beam Scanning Intensity-modulated Proton Therapy (IMPT)
  • Radiotherapy will consist of five fractions, delivered once daily, with pencil beam scanning proton beam therapy using the defined dose in dose level 2 (35 Gy).
  • The use of Intensity Modulated Radiation Therapy (IMRT) with photon beam therapy is permitted at the discretion of the treating investigator in order to avoid extended treatment delays due to logistical reasons (e.g. machine downtime).
Radiation: Hypofractionated Pencil-Beam Scanning Intensity-modulated Proton Therapy
When feasible it is strongly recommended that radiotherapy begin on a Monday
Other Names:
  • IMPT
Device: MEVION S250i Hyperscan and Adaptive Aperture Proton Therapy Machine
-The device that will administer the IMPT
Experimental: Dose Level 3: Hypofractionated Pencil-Beam Scanning Intensity-modulated Proton Therapy (IMPT)
  • Radiotherapy will consist of five fractions, delivered once daily, with pencil beam scanning proton beam therapy using the defined dose in dose level 3 (40 Gy).
  • The use of Intensity Modulated Radiation Therapy (IMRT) with photon beam therapy is permitted at the discretion of the treating investigator in order to avoid extended treatment delays due to logistical reasons (e.g. machine downtime).
Radiation: Hypofractionated Pencil-Beam Scanning Intensity-modulated Proton Therapy
When feasible it is strongly recommended that radiotherapy begin on a Monday
Other Names:
  • IMPT
Device: MEVION S250i Hyperscan and Adaptive Aperture Proton Therapy Machine
-The device that will administer the IMPT
Experimental: Dose Level -1: Hypofractionated Pencil-Beam Scanning Intensity-modulated Proton Therapy (IMPT)
  • Radiotherapy will consist of five fractions, delivered once daily, with pencil beam scanning proton beam therapy using the defined dose in dose level -1 (25 Gy).
  • The use of Intensity Modulated Radiation Therapy (IMRT) with photon beam therapy is permitted at the discretion of the treating investigator in order to avoid extended treatment delays due to logistical reasons (e.g. machine downtime).
Radiation: Hypofractionated Pencil-Beam Scanning Intensity-modulated Proton Therapy
When feasible it is strongly recommended that radiotherapy begin on a Monday
Other Names:
  • IMPT
Device: MEVION S250i Hyperscan and Adaptive Aperture Proton Therapy Machine
-The device that will administer the IMPT

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Maximum Tolerated Dose (MTD) of Reirradiation Using Hypofractionated IMPT
Time Frame: From start of treatment through 6 months
  • MTD is defined as the dose associated with a 35% probability of dose-limiting toxicity (DLT).

  • DLT is defined as any toxicity listed below that occurs within 6 months from start of treatment and is considered possibly, probably, or definitely related to proton reirradiation:

    • Any grade 5 toxicities
    • Any grade 4-5 GI toxicities
    • Bowel obstruction
    • Grade 3-5: diarrhea; anal, colonic, or bowel ulcers; bladder perforation; any fistula formations; peripheral motor/sensory neuropathy of the pelvis above baseline; osteonecrosis/soft tissue necrosis; radiation dermatitis; hematuria; hematochezia; bowel/pelvic hemorrhage; reproductive tract toxicity
  • Toxicity will be graded using CTCAE v5
From start of treatment through 6 months

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Clinical Complete Response Rate
Time Frame: Within 6 weeks to 3 months post-completion of radiation therapy (range 7-14 weeks)
-DRE, endoscopy, and cross-sectional imaging will be used to measure clinical complete response rate
Within 6 weeks to 3 months post-completion of radiation therapy (range 7-14 weeks)
Median Freedom From Locoregional Progression (FFLP)
Time Frame: Through completion of follow-up (full range 1.81 months-13.87 months)
-Defined as time from end of radiation therapy to date of first instance of local or regional tumor progression
Through completion of follow-up (full range 1.81 months-13.87 months)
Median Overall Survival (OS)
Time Frame: Through completion of follow-up (full range 4.4 months to 13.87 months)
Defined as time from end of radiation therapy to date that at least 50% of patients died
Through completion of follow-up (full range 4.4 months to 13.87 months)
Median Progression-free Survival (PFS)
Time Frame: Through completion of follow-up (full range 1.81 months-13.87 months)
-Defined as time from end of radiation therapy to the earliest date of locoregional progression, distant progression, or death from any cause
Through completion of follow-up (full range 1.81 months-13.87 months)
Median Change in Quality of Life (QoL) Score as Measured by The European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 (EORTC QLQ-C30)
Time Frame: Assessed at pre-treatment (baseline), 1-2 weeks, 3 months, 6 months, 9 months, and 12 months post-treatment
30 question survey which assesses patient well-being with 5 functional scales, 9 symptom scales, & global health scale. Scores for each scale range from 0-100. Higher score for the functional scale & global health represent high functioning, while high score for symptom scale represents high symptomatology. Median scores were taken for each scale for each dose level and the different between pre-treatment and post-treatment scores were calculated to determine change in score over time. For functional scales and global health status, negative values represent improved functionality/quality of life, while positive values represent diminished functionality. For symptom scales, the opposite is true. If patients did not complete the the survey at each time point, their data was censored. Data values were averaged prior to 3 months. Differences were taken between baseline values and the average value calculated of post-RT up to 3 months.
Assessed at pre-treatment (baseline), 1-2 weeks, 3 months, 6 months, 9 months, and 12 months post-treatment
Median Change in Quality of Life (QoL) Score as Measured by The European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 (EORTC QLQ-C30)
Time Frame: Assessed at pre-treatment (baseline), 1-2 weeks, 3 months, 6 months, 9 months, and 12 months post-treatment
30 question survey which assesses patient well-being with 5 functional scales, 9 symptom scales, & global health scale. Scores for each scale range from 0-100. Higher score for the functional scale & global health represent high functioning, while high score for symptom scale represents high symptomatology. Median scores were taken for each scale for each dose level and the different between pre-treatment and post-treatment scores were calculated to determine change in score over time. For functional scales and global health status, negative values represent improved functionality/quality of life, while positive values represent diminished functionality. For symptom scales, the opposite is true. If patients did not complete the survey at each time point, their data was censored. Data values were averaged from 3-12 months. Differences were taken between baseline values and the average value calculated of post-RT from 3-12 months.
Assessed at pre-treatment (baseline), 1-2 weeks, 3 months, 6 months, 9 months, and 12 months post-treatment
Median Change in Quality of Life (QoL) Score as Measured by the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire Colorectal Cancer Module 29 (EORTC QLQ-CR29)
Time Frame: Assessed at pre-treatment (baseline), 1-2 weeks, 3 months, 6 months, 9 months, and 12 months post-treatment
29 question survey which assesses quality of life for patients with colorectal cancer including functional & symptom status. The survey includes 4 multi-item scales & 19 single-item scales. Scores are linearly transformed to provide a score from 0-100. A high score for functional scales represents high level of functioning, while a high score for symptom scale represents high level of symptoms. Median scores were taken for each scale & the difference between baseline & varying time points was reported. Negative value represents improved function for a functional scale item, & worsening symptoms for symptom scale items. Positive values represent the converse. If patients did not complete the survey at each time point, their data was censored. Data values were averaged prior to 3 months. Differences were taken between pre-treatment (baseline) values and the average value calculated of post-RT up to 3 months.
Assessed at pre-treatment (baseline), 1-2 weeks, 3 months, 6 months, 9 months, and 12 months post-treatment
Median Change in Quality of Life (QoL) Score as Measured by the by the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire Colorectal Cancer Module 29 (EORTC QLQ-CR29)
Time Frame: Assessed at pre-treatment (baseline), 1-2 weeks, 3 months, 6 months, 9 months, and 12 months post-treatment
29 question survey which assesses quality of life for patients with colorectal cancer including functional & symptom status. The survey includes 4 multi-item scales & 19 single-item scales. Scores are linearly transformed to provide a score from 0-100. A high score for functional scales represents high level of functioning, while a high score for symptom scale represents high level of symptoms. Median scores were taken for each scale & the difference between baseline & varying time points was reported. Negative value represents improved function for a functional scale item, & worsening symptoms for symptom scale items. Positive values represent the converse. If patients did not complete the survey at each time point, their data was censored. Data values were averaged from 3-12 months. Differences were taken between baseline values and the average value calculated of post-RT from 3-12 months
Assessed at pre-treatment (baseline), 1-2 weeks, 3 months, 6 months, 9 months, and 12 months post-treatment
Frequency of Treatment-related Acute Adverse Events as Measured by CTCAE v 5.0
Time Frame: From start of treatment through 3 months after completion of radiation therapy (estimated to be 3 months and 1 week)
From start of treatment through 3 months after completion of radiation therapy (estimated to be 3 months and 1 week)
Frequency of Treatment-related Late Adverse Events as Measured by CTCAE v 5.0
Time Frame: From 3 month post-completion of radiation therapy to 12 months post-completion of radiation therapy
From 3 month post-completion of radiation therapy to 12 months post-completion of radiation therapy

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Washington University School of Medicine

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Michael Waters, M.D., Washington University School of Medicine

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
May 4, 2021

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
July 29, 2024

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
November 18, 2024

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
March 29, 2021

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
March 29, 2021

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
April 1, 2021

Study Record Updates

Last Update Posted (Estimated)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
September 29, 2025

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
September 15, 2025

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
September 1, 2025

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 202103218

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

Yes

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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