Recruiting

Skipping surgery after immunotherapy for rectal cancer

Plain-English translation of NCT04643041 on ClinicalTrials.gov ↗ · Source last updated April 2026 · Translation generated June 2026 · How we translate trials

This study doesn't follow the usual testing phases — it may be an observational study or a different type of research.

What is this trial?

This trial is testing whether patients with rectal cancer that has a specific genetic feature (called dMMR or MSI-H) can safely skip surgery after receiving PD-1 monoclonal antibody immunotherapy. The medication has already shrunk some patients' tumors completely. This study asks: if the tumor disappears completely, do patients still need surgery, or can doctors simply watch and wait?

Standard rectal cancer treatment usually involves surgery, often combined with chemotherapy or radiation. These treatments can cause serious side effects like loss of bowel or sexual function, chronic pain, and emotional distress. This trial exists because the new treatment has shown promise in making tumors disappear entirely, raising the question of whether some patients might avoid surgery altogether.

Do you qualify?

You likely qualify if…

you have been diagnosed with rectal adenocarcinoma (a specific type of rectal cancer)
your tumor has the specific genetic feature called dMMR or MSI-H
your tumor is located in the lower part of the rectum
you have completed 6 courses of PD-1 monoclonal antibody therapy
imaging and biopsy tests confirm your tumor has completely disappeared
you have never had rectal surgery or previous chemotherapy or radiation

You likely don't qualify if…

you have serious heart problems, uncontrolled high blood pressure, or recent heart attack
you have HIV, active hepatitis B or C, or active tuberculosis
you have a history of other cancers in the past 5 years
you have an active autoimmune disease or history of autoimmune conditions like lupus or rheumatoid arthritis
you are currently taking immunosuppressant medications or long-term steroids

What participation looks like

After your tumor has completely disappeared from the immunotherapy treatment, you would enter a "watch and wait" phase instead of having surgery. This means you would have regular follow-up visits with imaging scans and possibly biopsies to carefully monitor your rectal area. The study will track whether your tumor stays gone, whether it comes back, and whether this approach is safe and effective over time.

AI-generated summary from trial data · Jun 9, 2026 · Not medical advice

Trial locations(1 site)

China

Sun Yatsen University, Guangzhou, Guangdong