Radiation proctitis is inflammation of the rectum caused by radiation therapy for pelvic cancers. Acute radiation proctitis occurs during and shortly after radiation treatment and causes mild, self-limiting symptoms. Chronic radiation proctitis develops months to years later and significantly reduces quality of life, with bleeding being the main symptom. Flexible sigmoidoscopy and biopsy can identify ulceration, fibrosis, and other changes. Topical formalin application or argon plasma coagulation provides short-term relief but multiple treatments are often needed and relapse is common. Surgery is reserved for complicated cases that fail other management. Further research through prospective randomized trials is still needed.

1. Radiation Proctitis Dr Darren Tonkin Colorectal Registrar

2. Contents Acute radiation proctitis Chronic radiation proctitis Pathology Investigation Management Conclusions

3. Acute Radiation Proctitis (ARP) ~75% of pts treated with pelvic XRT Occurs during treatment and for several weeks after completion Symptoms usually mild and self limiting Symptomatic treatment only

4. Clinical Manifestations - ARP Diarrhoea (predominant) Mucous discharge Tenesmus Abdominal & anal pain Rectal bleeding (uncommon)

5. Chronic Radiation Proctitis (CRP) 2 to 20% of patients Months to yrs following XRT (median 8 - 13 months) Significant negative effect on quality of life Natural history poorly understood

6. Clinical Manifestations - CRP Bleeding (70%) Mucous discharge Diarrhoea Pain Urgency Tenesmus Incontinence Fistulae Stricture Obstruction Perforation

7. Pathology Mucosal ulceration Eosinophilic crypt abscesses Obliterative endarteritis Submucosal fibrosis Neovascularization (telangiectasia)

8. Influencing Factors - CRP Radiotherapy regimen Radiation dose (>50Gy) N o. fields Shielding Delivery method (intracavity > EBRT) Radiosensitizers, chemotherapy Patient Factors Diabetes Previous abdominal surgery Hypertension Age

9. Investigation (1) Flexible sigmoidoscopy, colonoscopy ± Bx Pale mucosa + telangiectasia Ulceration, bleeding, fibrosis

10. Investigation (2) CT chest, abdomen Contrast enema Anorectal manometry Transanal ultrasound

11. Management - Medical Enemas (no proven efficacy) Steroids Sucralfate 5-aminosalicylates Butyrate Hyperbaric O 2 Limited data Expensive Time-consuming (20 - 40 treatments required)

12. Management - Endoscopic (1) Topical Formalin Adapted from use in radiation cystitis 4% formalin solution applied Contact time 2-3 min 59 – 100% short term response Minimal relapse Protection of perianal skin important GA often required Fissures, ulcers, strictures reported

13. Management - Endoscopic (2) Diathermy Electrode “sticks” to mucosa Unpredictable depth of coagulation Ineffective in excessive bleeding

14. Management - Endoscopic (3) Laser (Nd:YAG, Argon) 87% short term response 2 - 3 treatments required 70% relapse after cessation of bleeding Maintenance treatments required at 7 month intervals Disadvantages Expensive Inaccessible Risk of perforation Protective precautions required

15. Management - Endoscopic (4) Argon Plasma Coagulation Bipolar diathermy current via ionized Argon gas stream Effective in short term 2 - 4 treatments required Minimal relapse Advantages Reduced perforation risk Easier painting of large areas More affordable/accessible than laser Disadvantages Rectal strictures reported Ineffective with excessive bleeding Overdistension with Argon gas

16. Management – Surgery (1) Complicated disease Strictures Fistulae Refractory bleeding High complication rate (15 - 79%) Postop fistulae (up to 25%) Anastomotic leaks Wound dehiscence Pelvic sepsis

17. Management – Surgery (2) Excision - preferred approach Anterior resection + reconstruction APR – perineal wound breakdown in 45% Diversion Prior to definitive surgery for strictures or fistulae Not indicated for bleeding

18. Conclusions Medical management of little benefit Topical formalin or Argon plasma coagulation most effective Surgery as last resort in complicated cases Poorly investigated in the past Prospective, randomized trials required