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NCT Number: NCT05081024

Establishing a ctDNA Biomarker to Improve Organ Preserving Strategies in Patients With Rectal Cancer

This study measures the levels of circulating tumor DNA (ctDNA) in patients with stage II-III rectal cancer before, during, and after treatment to find out if the presence or absence of ctDNA in patient's blood using the Signatera test can be used to gauge how different treatments may affect rectal cancer. ctDNA is DNA from the rectal cancer that is circulating in the blood. The purpose of this study is to understand if the way rectal tumors respond to standard treatment can be associated with varying levels of ctDNA.

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Key information

Conditions

Rectal Adenocarcinoma Colorectal Neoplasms Digestive System Diseases Digestive System Neoplasms Gastrointestinal Diseases Gastrointestinal Neoplasms Intestinal Diseases Intestinal Neoplasms Neoplasms Neoplasms by Site Rectal Diseases Rectal Neoplasms Stage II Rectal Cancer AJCC v8 Stage IIA Rectal Cancer AJCC v8 Stage IIB Rectal Cancer AJCC v8 Stage IIC Rectal Cancer AJCC v8 Stage III Rectal Cancer AJCC v8 Stage IIIA Rectal Cancer AJCC v8 Stage IIIB Rectal Cancer AJCC v8 Stage IIIC Rectal Cancer AJCC v8

Age range

18 year and older

Sex eligibility

All sexes

Study type

Observational

Primary location

OHSU Knight Cancer Institute, Portland, Oregon, United States

Loading trial locations.

About this study

PRIMARY OBJECTIVE:

I. To estimate the percentage of participants that achieve complete clinical response.

SECONDARY OBJECTIVES:

I. To assess circulating tumor deoxyribonucleic acid (ctDNA) status among participants receiving total neoadjuvant therapy (TNT).

II. To assess molecular residual disease (MRD i.e., ctDNA status). III. To assess the rate of transabdominal surgery. IV. To assess the rate pathological complete response after surgery. V. To assess the rate of watch and -wait (W&W) after TNT. VI. To assess disease-free survival (DFS). VII. To assess overall survival (OS).

EXPLORATORY OBJECTIVES:

I. To characterize ctDNA clearance or non-clearance patterns during TNT. II. To correlate ctDNA levels with a participant's pathological features. III. To preliminary assess the prognostic performance of ctDNA levels in relation to participant's clinical outcome.

OUTLINE:

Patients undergo collection of blood samples at baseline (before any neoadjuvant therapy), every 2 months while undergoing TNT, and then every 3 months for up to 3 years after completion of TNT. Patients' medical records are also reviewed. Patients may undergo collection of tissue sample if an archival tissue sample is not available.

Who can participate

Healthy volunteers accepted: No

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

Inclusion criteria

  • Participant must provide written informed consent before any study-specific procedures or interventions are performed
  • Participants aged >= 18 years
  • Pathologically-confirmed stage II or III primary adenocarcinoma of the rectum:
  • T3N0M0 - T4bN2M0

Exclusion criteria

  • Has radiologic evidence of distant metastases at the time of screening/enrollment
  • Has received prior treatment for their rectal adenocarcinoma
  • Requires or has received blood transfusion within 1 month of study enrollment

Treatment and study plan

Biopsy

Procedure

Undergo biopsy

Other names: BIOPSY_TYPE, Bx

Biospecimen Collection

Procedure

Undergo collection of blood and/or tissue samples

Other names: Biological Sample Collection

Electronic Health Record Review

Other

Medical records are reviewed

Primary outcomes

  1. Complete clinical response (cCR)

    Time frame: From time of treatment start up to date of completing total neoadjuvant therapy (TNT), up to 3 months.

    cCR following TNT will be analyzed using the TNT analysis set. Proportions of participants that achieved cCR will be calculated and the exact 95% confidence interval (CI) will be presented.

Secondary outcomes

  1. Positive circulating tumor deoxyribonucleic acid (ctDNA)

    Time frame: From date of baseline measure of ctDNA (i.e., number of mutant molecules per mL) to date of until the date of first documented progression, up to 3 years.

    The proportion of ctDNA positive participants (at baseline, throughout TNT, and follow-up) and its exact 95% CI will be evaluated using the ctDNA analysis set. Where appropriate, sub-analyses will be conducted using populations that underwent surgery or were monitored using a watch and wait (W&W) strategy.

  2. Positive ctDNA after completing TNT

    Time frame: From date of baseline measure of ctDNA (i.e., number of mutant molecules per mL) to date of until the date of first documented progression, up to 3 years

    The proportion of ctDNA positive participants (at baseline, throughout TNT, and follow-up) and its exact 95% CI will be evaluated using the ctDNA analysis set. Where appropriate, sub-analyses will be conducted using populations that underwent surgery or were monitored using a W&W strategy.

  3. Rate of transabdominal surgery

    Time frame: Up to 3 years following completion of TNT

    Will be evaluated using the TNT analysis set. The corresponding exact 95% CI will also be presented.

  4. Rate of pathological complete response (pCR)

    Time frame: From start of treatment until completion of surgery, up to 3 years.

    Will be evaluated using the TNT analysis set. The corresponding exact 95% CI will also be presented.

  5. Rate of watch and wait strategy

    Time frame: Up to 3 years following completion of TNT

    Will be evaluated using the TNT analysis set. The corresponding exact 95% CI will also be presented.

  6. Disease-free survival

    Time frame: Time between the date of surgery (or W&W population, the date of completing TNT) and the date of local or metastatic recurrence or death from any cause, assessed up to 3 years following completion of TNT

    Will be estimated using the Kaplan-Meier method.

  7. Overall survival

    Time frame: Time between the date of signed consent to the date of death from any cause, assessed up to 3 years following completion of TNT

    Will be estimated using the Kaplan-Meier method.

Other outcomes

  1. ctDNA status

    Time frame: From date of baseline measure of ctDNA (i.e., number of mutant molecules per mL) to date of until the date of first documented progression, up to 3 years

    positive versus negative results per test results

  2. Positive ctDNA by clinical characteristics

    Time frame: From date of baseline measure of ctDNA to date of recurrence or death from any cause, assessed up to 3 years following completion of TNT

    association or recurrence on ctDNA test and standard imaging

  3. Sensitivity

    Time frame: From date of baseline measure of ctDNA to date of recurrence or death from any cause, assessed up to 3 years following completion of TNT

    Sensitivity and specificity will be calculated using complete clinical response (yes versus [vs.] no), or tumor recurrence (yes vs. no) as reference standard.

  4. Specificity

    Time frame: From date of baseline measure of ctDNA to date of recurrence or death from any cause, assessed up to 3 years following completion of TNT

    Sensitivity and specificity will be calculated using complete clinical response (yes vs. no), or tumor recurrence (yes vs. no) as reference standard.

Sponsors and collaborators

Lead sponsor

OHSU Knight Cancer Institute

Other

Collaborators

  • Natera, Inc.

Registry information

Important dates

Study start
2021
Primary completion
2026
Study completion
2026
First posted
Oct 18, 2021
Registry last updated
Sep 25, 2025

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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