[Clinical classification, characteristics, and prognosis of chronic radiation-induced rectal injury: a single-center analysis of 1131 cases].

Objective: To analyze the clinical characteristics and endoscopic manifestations of patients with chronic radiation-induced rectal injury (RLRI) based on single-center data, and to explore the treatment modalities and prognostic outcomes associated with different clinical classifications. Methods: A retrospective descriptive case series analysis was performed. Patients with RLRI treated at the Sixth Affiliated Hospital, Sun Yat-sen University between March 2008 and December 2024 were enrolled, and a clinical database was established. Baseline clinical data of all patients were collected and sorted, and long-term follow-up was conducted to evaluate symptomatic remission. Symptom remission was subjectively assessed based on patients' self-reported symptoms during follow-up, categorized as remission, no remission, or disease progression. Clinical classification, clinical characteristics, and treatment outcomes of RLRI were further analyzed. Results: A total of 1 131 patients were included, among whom 1 069 (94.5%) were female, with a mean age of (58.7±10.3) years. Cervical cancer was the primary malignancy in 999 patients (88.3%). The total radiation dose delivered was (74.1±23.0) Gy. The median interval from completion of radiotherapy to onset of symptomatic presentation was 13.8 months. The predominant presenting symptom was hematochezia in 978 patients (86.5%), followed by anorectal and sacrococcygeal pain 299 cases(26.4%) and abdominal pain 285 cases(25.2%). Concurrent radiation-induced urinary tract injury occurred in 360 patients (31.8%), and concurrent radiation-induced small bowel injury in 190 patients (16.8%). Based on clinical manifestations, endoscopic findings and imaging alterations, patients were classified into four subtypes: telangiectatic type (547 cases, 48.4%), mixed type (559 cases, 49.4%), ulcerative type (23 cases, 2.0%), and stricturing type (2 cases, 0.2%). In terms of treatments, 1 045 patients (92.4%) received pharmacotherapy overall; 229 patients (20.2%) underwent resection of the diseased rectal segment. Mixed-type RLRI accounted for the largest number of rectal resections (176 cases, 31.5%), while ulcerative RLRI had the highest surgical resection proportion (10/23, 43.5%), and telangiectatic RLRI the lowest (7.7%,42/547). A total of 269 patients (23.8%) received diverting stoma creation: only 93 patients with telangiectatic RLRI (17.0%, 93/547) versus 168 patients with mixed-type RLRI (30.1%,168/559). Endoscopic argon plasma coagulation (APC) was administered to 172 patients with telangiectatic RLRI (31.4%) and 96 patients with mixed-type RLRI (17.2%). Thirty-five patients (3.1%) received transanal formalin therapy, predominantly telangiectatic RLRI (29 cases), with 6 cases of mixed-type RLRI. Among the 229 patients who underwent diseased bowel resection, the main surgical procedures included Parks procedure (65 cases, 28.4%), Bacon pull-through resection (89 cases, 38.9%), Dixon anterior resection (19 cases, 8.3%), Hartmann procedure (10 cases, 4.4%), and other procedures (46 cases, 20.1%). Of the 269 patients receiving isolated diverting stoma surgery, 252 underwent loop transverse colostomy (93.7%), 15 loop ileostomy (5.6%), and 2 sigmoid colostomy (0.7%). Follow-up was completed by December 2025, covering 816 patients (72.1%). Among these, 171 patients died (21.0%, 171/816), and 56 deaths (32.7%, 56/171) were attributed to tumor recurrence or metastasis. Symptom relief status was documented in 648 patients, with an overall symptom relief rate of 78.4%(508/648). Subgroup relief rates were 84.9% for mixed-type RLRI (254/299), 72.6% for telangiectatic RLRI (244/336), complete relief in both stricturing-type patients, and relief in 8 out of 11 ulcerative-type patients. Persistent unresolved symptoms were reported in 140 patients (21.6%), most of whom had telangiectatic RLRI (92 cases). Conclusion: Significant differences exist among different clinical classifications of chronic radiation-induced rectal injury in terms of clinical features, treatment choices, and prognosis. Therefore, treatment strategies should be comprehensively evaluated based on clinical symptoms, endoscopic findings, and imaging manifestations to develop individualized treatment plans.