Hyperbaric Oxygen Therapy for Late Radiation-Induced Duodenal Toxicity After Stereotactic Body Radiotherapy in a Patient with Cholangiocellular Carcinoma: A Unique Case Report.

Stereotactic body radiotherapy (SBRT) is an effective and increasingly utilized treatment modality for abdominal tumors, offering high rates of local control with generally acceptable toxicity profiles. Nevertheless, rare but severe late gastrointestinal complications, including radiation-induced ulceration, may occur and significantly impair patients' quality of life, as well as continuation of oncologic treatment. Hyperbaric oxygen therapy (HBOT) has shown potential benefit in the management of chronic radiation-induced tissue injury, although evidence regarding its role following SBRT remains limited. We report the case of a 75-year-old woman with cholangiocellular carcinoma who developed severe radiation-induced duodenal ulceration following liver SBRT, presenting with persistent postprandial pain, nausea, vomiting, and substantial weight loss despite standard supportive treatment. Helicobacter pylori testing was negative, non-steroidal anti-inflammatory drug use was excluded, and histopathology showed chronic inflammatory and fibrotic mucosal injury with reactive epithelial changes. Despite high-dose proton pump inhibition, bismuth subcitrate, and nutritional support, symptoms and endoscopic ulceration persisted. HBOT was administered at 2.4 atmospheres absolute for 60 min over 30 sessions. Clinical improvement was noted after three sessions, and treatment was completed without adverse effects. Follow-up endoscopy demonstrated almost complete ulcer regression, with complete symptom resolution, improved oral intake, and a 10 kg weight gain. To the best of our knowledge, this represents the first reported case describing the successful use of HBOT as a potentially effective adjunctive treatment for severe radiation-induced duodenal ulceration following liver SBRT in a patient with cholangiocarcinoma. Although encouraging, this observation should be interpreted cautiously, and prospective clinical studies are needed to further evaluate the efficacy, safety, and optimal timing of HBOT in this setting.