Plasma GLP-2 Dynamics and Acute Radiation Enteritis After Abdominopelvic Radiotherapy

This is a single-center, prospective observational cohort study involving approximately 50 adults receiving abdominopelvic radiotherapy. Participants will receive radiotherapy and other supportive treatment according to routine clinical practice. The study will not alter the participants' prescribed treatment or assign any study-specific therapeutic intervention.

Residual blood samples from routine clinical testing will be collected at three time points: before radiotherapy, at the completion of radiotherapy, and one month after radiotherapy. The primary outcome is the plasma glucagon-like peptide-2 (GLP-2) level and its change over time. Additional assessments will include diamine oxidase, D-lactate, interleukin-6, tumor necrosis factor-alpha, and interleukin-1 beta. Citrulline, intestinal fatty acid-binding protein, and metabolomic analyses may also be performed when feasible.

Clinical information will include demographic characteristics, cancer and treatment characteristics, gastrointestinal symptoms, radiotherapy dose parameters, nutritional status, laboratory findings, and quality-of-life assessments. After follow-up, participants will be classified according to whether acute radiation enteritis occurred. GLP-2 levels and longitudinal changes will be compared between participants with and without acute radiation enteritis. Associations between GLP-2 and intestinal injury markers, inflammatory factors, symptom severity, radiotherapy dose parameters, nutritional status, and quality of life will also be evaluated.

Inclusion criteria

Inclusion criteria

• Age 18 to 75 years.
• Diagnosed with a malignancy and scheduled to receive abdominopelvic radiotherapy.
• No active enteritis or moderate-to-severe diarrhea before radiotherapy.
• Expected to complete the planned course of radiotherapy and the 1-month post-radiotherapy follow-up.
• Able to complete clinical data collection, gastrointestinal symptom assessment, nutritional assessment, quality-of-life assessment, and collection of residual peripheral venous blood samples from routine clinical testing.
• Willing to participate and able to provide written informed consent.

Exclusion criteria

• Moderate-to-severe diarrhea, active inflammatory bowel disease, intestinal obstruction, short bowel syndrome, or severe malabsorption before radiotherapy.
• Previous radiotherapy to the same abdominopelvic region.
• Severe cardiac, hepatic, or renal failure.
• Active infection, severe systemic inflammatory response, or active autoimmune disease.
• Receipt during the study of treatments considered by the investigator to substantially affect intestinal hormones, inflammatory markers, or intestinal barrier function and interfere with the study results.
• Pregnancy or breastfeeding.
• Any other condition that, in the investigator's judgment, makes the individual unsuitable for participation.