How opioid-free, opioid-sparing, and opioid-based anesthesia affect immune markers and cancer cell behavior after colorectal cancer surgery

Effect of Opioid-Free, Opioid-sparing Versus Opioid-based Anesthesia on Perioperative NETs and Cancer Cell Malignancy in Patients Undergoing Surgery for Colorectal Cancer: A Randomized, Controlled Trial

NA · Fudan University · NCT07264556

This trial will test whether opioid-free or opioid-sparing anesthesia versus standard opioid-based anesthesia changes immune markers and affects cancer cell behavior in adults having elective colorectal cancer surgery.

Quick facts

PhaseNA
Study typeInterventional
Enrollment90 (estimated)
Ages18 Years to 80 Years
SexAll
SponsorFudan University (other)
Drugs / interventionschemotherapy
Locations1 site (Shanghai, Shanghai Municipality)
Trial IDNCT07264556 on ClinicalTrials.gov

What this trial studies

Adults aged 18–80 with ASA physical status I–III undergoing elective colorectal cancer surgery were randomized to receive opioid-free anesthesia, opioid-sparing anesthesia, or conventional opioid-based anesthesia. Blood samples were collected before surgery and 24 hours after surgery to measure neutrophil extracellular trap markers (including MPO and citrullinated histone H3) as primary endpoints. Secondary endpoints include the effect of postoperative serum on colorectal cancer cell malignancy in laboratory assays, postoperative pain scores, adverse events, and recovery profiles. The opioid-based arm uses remifentanil and sufentanil intraoperatively with postoperative patient-controlled IV analgesia, while the other arms reduce or omit intraoperative and postoperative opioids.

Who should consider this trial

Good fit: Adults 18–80 years old with ASA physical status I–III who are scheduled for elective colorectal cancer surgery under general anesthesia at the enrolling center.

Not a fit: Patients with prior colorectal surgery, recent chemotherapy or radiotherapy within 8 weeks, opioid addiction, serious major organ disease, or contraindications to the anesthetic techniques are excluded and unlikely to benefit from participation.

Why it matters

Potential benefit: If successful, changing the anesthesia approach could reduce pro‑tumor immune signals after surgery and potentially lower cancer cell aggressiveness, which might improve long‑term outcomes.

How similar studies have performed: Prior research has suggested opioids can alter immune function and perioperative factors may influence cancer biology, but results are mixed and direct comparisons of opioid-free versus opioid-sparing versus opioid-based approaches remain relatively novel.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* aged 18-80 years old,
* American Society of Anesthesiologists physical status I-III,
* elective colorectal cancer surgery under general anesthesia

Exclusion Criteria:

* previous history of colorectal surgery,
* addicted to opioids,
* serious major mental or physical illness (heart, pulmonary, hepatic, or renal diseases),
* radiotherapy or chemotherapy history within 8 weeks prior to the surgery,
* contraindications to anesthetic agents or epidural.

Where this trial is running

Shanghai, Shanghai Municipality

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 →

Conditions: Colorectal Cancer, Opioid-free Anesthesia, NETs, Opioid free anesthesia, Neutrophil extracellular trapping markers, colorectal cancer

Last reviewed 2026-05-15 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.