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.
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.
Study Type
OBSERVATIONAL
Enrollment
50
Undergo biopsy
Undergo collection of blood and/or tissue samples
Medical records are reviewed
OHSU Knight Cancer Institute
Portland, Oregon, United States
RECRUITINGFred Hutch
Seattle, Washington, United States
RECRUITINGComplete clinical response (cCR)
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.
Time frame: From time of treatment start up to date of completing total neoadjuvant therapy (TNT), up to 3 months.
Positive circulating tumor deoxyribonucleic acid (ctDNA)
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.
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 ctDNA after completing TNT
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.
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
Rate of transabdominal surgery
Will be evaluated using the TNT analysis set. The corresponding exact 95% CI will also be presented.
Time frame: Up to 3 years following completion of TNT
Rate of pathological complete response (pCR)
Will be evaluated using the TNT analysis set. The corresponding exact 95% CI will also be presented.
Time frame: From start of treatment until completion of surgery, up to 3 years.
Rate of watch and wait strategy
Will be evaluated using the TNT analysis set. The corresponding exact 95% CI will also be presented.
Time frame: Up to 3 years following completion of TNT
Disease-free survival
Will be estimated using the Kaplan-Meier method.
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
Overall survival
Will be estimated using the Kaplan-Meier method.
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
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