Classification of Actinic Proctitis
Actinic proctitis is classified by timing into acute (self-limited, lasting approximately 3 months) and chronic (developing months to years after radiation therapy), and by severity ranging from mild mucosal changes to severe complications including ulceration, stricture, or perforation. 1, 2
Temporal Classification
The primary classification system for actinic (radiation-induced) proctitis distinguishes between two distinct temporal patterns:
Acute actinic proctitis: Self-limited condition that develops during or immediately after radiation therapy and typically resolves within approximately 3 months 2
Chronic actinic proctitis: Develops months to years after completion of radiation therapy, with an incidence of approximately 5-20% in patients who received pelvic radiation (particularly for prostate cancer) 2
Severity-Based Classification
Chronic actinic proctitis can be further classified by severity of complications:
Mild disease: Characterized by telangiectasias, friability, and minor mucosal changes visible on endoscopy 1
Moderate disease: Presents with more significant ulceration and bleeding requiring intervention 1
Severe disease: Includes complications such as stricture formation, perforation, or fistula development requiring surgical management 1, 3
Important Clinical Context
Radiation-induced colitis should be considered a separate clinical entity from ulcerative colitis and inflammatory bowel disease, requiring a different diagnostic and therapeutic approach. 1 This distinction is critical because:
- The pathophysiology differs fundamentally from inflammatory bowel disease 1
- Treatment strategies are distinct from those used for ulcerative proctitis 1
- The Montreal and Paris classification systems used for ulcerative colitis (E1 proctitis, E2 left-sided, E3 extensive) do not apply to radiation-induced disease 4
Endoscopic Features
The endoscopic appearance helps classify severity and includes telangiectasias, friability, ulceration, and strictures, with these findings supported by high-level evidence 1. Severe cases may demonstrate stenosis or perforation requiring surgical intervention such as proctosigmoidectomy 3.