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Comparing chemotherapy alone versus chemotherapy with radiation for rectal cancer treatment

A Phase 3 Randomized Trial Of Neoadjuvant Chemotherapy, Excision And Observation Versus Chemoradiotherapy For Early Rectal Cancer

Phase 3 Interventional Canadian Cancer Trials Group · NCT06205485

This study is testing whether giving chemotherapy alone is just as effective as combining it with radiation for people with early rectal cancer before their surgery.

Quick facts

PhasePhase 3
Study typeInterventional
Enrollment250 (estimated)
Ages18 Years and up
SexAll
SponsorCanadian Cancer Trials Group Research network
Drugs / interventionschemotherapy, radiation
Locations107 sites (Phoenix, Arizona and 106 other locations)
Trial IDNCT06205485 on ClinicalTrials.gov

What this trial studies

This study aims to determine whether neoadjuvant chemotherapy alone is as effective as a combination of chemotherapy and radiation therapy for patients with early rectal cancer. Participants will receive either a chemotherapy regimen (FOLFOX or CAPOX) for up to 12 weeks or a combination of chemotherapy and radiation for up to 6 weeks before undergoing surgery. The study will monitor side effects and assess the best surgical approach post-treatment, with follow-up appointments scheduled for up to 5 years. The goal is to evaluate cancer response rates and quality of life outcomes between the two treatment approaches.

Who should consider this trial

Good fit: Ideal candidates include adults aged 18 and older with early-stage rectal adenocarcinoma who meet specific MRI and CT imaging criteria.

Not a fit: Patients with advanced rectal cancer or those with contraindications to the protocol chemotherapy will not benefit from this study.

Why it matters

Potential benefit: If successful, this study could provide a less intensive treatment option that maintains effectiveness while potentially improving quality of life for rectal cancer patients.

How similar studies have performed: Other studies have shown promising results with similar approaches, but this specific comparison is novel.

Eligibility criteria

Show full inclusion / exclusion criteria 
Inclusion Criteria:

* Histologically confirmed invasive, well-moderately differentiated rectal adenocarcinoma, mismatch repair proficient.
* MRI stage cT1 not eligible for transanal surgery or cT2-T3ab\*. \* T3a: \<1mm depth invasion, T3b: 1-5mm depth of invasion.
* cN0 stage based on pelvic MRI - including absence of radiographic evidence of mesorectal nodal metastasis, tumour deposits or extramural venous invasion (EMVI).
* M0 stage based on no evidence of metastatic disease by CT imaging of chest, abdomen and pelvis.
* Mid to low-lying tumour eligible for transanal excision in the opinion of the treating surgeon.
* Medically fit to undergo radical TME surgery as per treating surgeon's decision.
* Participant is able (i.e. sufficiently fluent) and willing to complete the quality of life questionnaires in either English or French or Spanish.
* Age of at least 18 years.
* No contraindications to protocol chemotherapy.
* Adequate normal organ and marrow function: ANC ≥ x 10\^9/L; platelet count ≥ 100 x 10\^9/L; bilirubin \< 1.5 UNL, excluding Gilbert's syndrome; Estimated creatinine clearance of ≥ 50ml/min
* Patient must have an ECOG performance of \<2 (or Karnofsty ≥ 60%).
* Must be accessible for treatment and follow-up
* Males and females of reproductive potential must have agreed to use a highly effective contraceptive method during and for 6 months after completion of chemotherapy.
* HIV-infected patients on effective anti-retroviral therapy with undetectable viral load within 6 months are eligible for this trial.

Exclusion Criteria:

* Pathologic high-risk factors on diagnostic biopsy: high histologic grade (poorly differentiated), mucinous or signet ring histology.
* Patients with visible pelvic sidewall nodes on MRI.
* Patients with unequivocal determination of nodal disease that, in the opinion of the investigator, would prohibit protocol therapy administration.
* Previous pelvic radiation for any reason, including brachytherapy alone.
* Patients who have had primary lesion excised prior to enrollment. If a patient has had partial excision prior to enrollment, there must be gross residual disease endoscopically for patient to be eligible.
* Patients with a prior or concurrent malignancy whose natural history or treatment does not have the potential to interfere with the safety or efficacy assessment of the investigational regimen are eligible for this trial.
* Prior treatment for rectal cancer.
* Patients with known dihydropyrimidine dehydrogenase deficiency (DYPD).
* Potential trial participants should have recovered from clinically significant adverse events of their most recent therapy/intervention prior to enrollment.
* Patients with known history or current symptoms of cardiac disease, or history of treatment with cardiotoxic agents, should have a clinical risk assessment of cardiac function using the New York Heart Association Functional Classification. To be eligible for this trial, patients should be class 2B or better.
* Any contra-indications to undergo MRI imaging.
* Presence of anterior lesions above or near peritoneal reflection rendering the patient ineligible for a transanal tumour excision.
* T3 tumours invading or abutting the internal sphincter.

Where this trial is running

Phoenix, Arizona and 106 other locations

+57 more sites — see ClinicalTrials.gov for the full list.

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
View on ClinicalTrials.gov → Find more trials like this →
Conditions Rectal Cancer
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.