Recruiting

Proton versus standard radiation therapy for advanced rectal cancer

Plain-English translation of NCT04525989 on ClinicalTrials.gov ↗ · Source last updated August 2025 · Translation generated July 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 study is comparing two types of radiation therapy for people with locally advanced rectal cancer: proton beam radiation and standard photon radiation. Both are followed by chemotherapy (capecitabine and oxaliplatin) and surgery. Researchers want to see if proton therapy causes fewer gastrointestinal side effects and helps patients better tolerate the chemotherapy that comes after radiation.

There are currently no published studies comparing proton therapy to standard radiation therapy for advanced rectal cancer. This trial exists to fill that gap and see if the newer treatment might reduce painful side effects like nausea, diarrhea, and bowel problems that patients often experience during cancer treatment.

Do you qualify?

You likely qualify if…

you have been newly diagnosed with rectal cancer that has spread into nearby structures or lymph nodes (locally advanced disease)
you are at least 18 years old and in good enough health to receive chemotherapy
you have adequate blood counts, kidney function, and liver function as measured by blood tests within 5 weeks of enrollment
you are able to undergo MRI imaging and have had your cancer staged within the past 6 weeks
you are able to commit to follow-up care and provide written informed consent

You likely don't qualify if…

you have metastatic disease (cancer that has spread to distant organs) or a recurrent rectal tumor
you have a deficiency in an enzyme called DPD, which prevents you from safely receiving the chemotherapy used in this trial
you have active inflammatory bowel disease such as Crohn's disease or ulcerative colitis
you are pregnant or breastfeeding, or have significant heart disease or a recent heart attack (within 12 months)
you have symptoms of nerve damage (peripheral neuropathy) or cannot safely undergo an MRI scan

What participation looks like

You will be randomly assigned to receive either proton radiation or standard photon radiation — five treatments of radiation therapy over one week. After radiation, you'll receive four to six cycles of chemotherapy (given every 3 weeks over about 12 weeks), followed by surgery to remove the tumor. Throughout the process, you'll have regular clinic visits for imaging, blood tests, and check-ins to monitor your health and side effects.

AI-generated summary from trial data · Jul 18, 2026 · Not medical advice

Trial locations(9 sites)

Sweden

Karolinska University Hospital, Theme Cancer, Dept of Pelvic cancer, Stockholm, Solna

Gävle Hospital, Gävle

Sahlgrenska University Hospital, Gothenburg

Linköping University Hospital, Linköping

Skåne University Hospital, Lund