Radiation proctitis (RP) is an inflammation of the rectum that develops following radiation therapy directed at the pelvis, typically for cancers like prostate, rectal, or gynecological malignancies. This radiation exposure can injure the delicate lining of the rectum, leading to a range of symptoms and complications. Managing RP requires understanding whether the condition manifests in its acute or chronic form, as each has distinct timelines and underlying tissue damage. The duration and nature of this inflammation significantly affect a patient’s quality of life.
The Timeline of Radiation Proctitis
Acute radiation proctitis occurs during radiation treatment or within the first 90 days after therapy is completed. This phase is characterized by direct injury to the superficial mucosal cells of the rectum, leading to inflammation and cellular shedding. Acute symptoms are temporary and self-limiting, usually resolving within a few weeks to a few months after radiation exposure ends. While the long-term prognosis is generally favorable, acute gastrointestinal toxicity may increase the likelihood of late-stage complications. The acute phase usually concludes within six months of treatment.
Chronic, or late, radiation proctitis is a persistent condition that typically develops more than six months after the completion of radiation therapy, though it can appear years later. The median time of onset is often between 8 and 12 months after treatment. This late presentation involves irreversible changes to the deeper tissues of the rectal wall. The underlying pathology shifts from acute inflammation to progressive damage to small blood vessels, leading to tissue ischemia, fibrosis, and the formation of fragile, bleeding blood vessels called telangiectasias. Chronic RP can be persistent and may require active, long-term management, sometimes lasting for many years.
Recognizing Symptoms and Confirming Diagnosis
The symptoms of radiation proctitis generally affect bowel habits and comfort. Common symptoms in both acute and chronic phases include rectal urgency (tenesmus) and diarrhea, sometimes accompanied by excessive mucus discharge, particularly in the acute phase.
Rectal bleeding, or hematochezia, is a defining symptom and is often the most common presentation of chronic radiation proctitis. In the acute phase, bleeding is usually mild. In the chronic phase, it results from the fragile telangiectasias and can be persistent or severe enough to cause anemia. Patients may also experience rectal pain or discomfort, which is more common during the acute inflammatory period.
The diagnosis of radiation proctitis is initially based on the patient’s symptoms and history of pelvic radiation. Other causes of inflammation or bleeding, such as infection, must be ruled out. The most definitive confirmation method is endoscopy, such as a flexible sigmoidoscopy or colonoscopy, which allows for direct visualization of the rectal lining. During the procedure, the doctor looks for characteristic signs of the condition, such as mucosal inflammation and ulceration in the acute phase, or the presence of pale tissue and the distinctive, fragile telangiectasias in the chronic phase.
Treatment Options for Symptom Management
For acute radiation proctitis, treatment is primarily supportive and often involves conservative measures.
- Dietary adjustments, such as maintaining adequate hydration and following a low-residue diet, help manage diarrhea and urgency.
- Over-the-counter or prescription medications, including antidiarrheal agents like loperamide and antispasmodics, are used for symptom relief.
- Topical treatments, such as steroid or 5-aminosalicylate enemas, may be prescribed to reduce local inflammation.
- Sucralfate enemas are also employed as a protective agent that creates a barrier over the irritated mucosa.
For the persistent symptoms of chronic radiation proctitis, particularly bleeding, more specific interventions are required. Endoscopic procedures are frequently used to control bleeding by coagulating the fragile telangiectasias. Argon Plasma Coagulation (APC) delivers ionized argon gas to the mucosal surface, causing superficial heating and sealing off the damaged blood vessels. This technique is effective in controlling bleeding, often requiring just one or two treatment sessions.
If endoscopic treatments are unsuccessful or for widespread, severe bleeding, chemical cauterization using topical formalin application may be considered. Formalin works by chemically sealing the bleeding neovasculature. Another advanced treatment is Hyperbaric Oxygen Therapy (HBOT), which involves breathing pure oxygen in a pressurized chamber. HBOT promotes healing by increasing oxygen delivery to oxygen-starved areas, stimulating the growth of new blood vessels. Patients typically undergo multiple daily sessions over several weeks to achieve a significant reduction in chronic symptoms.