What is radiation proctitis?

Radiation proctitis, also known as radiation-induced proctopathy, is defined as an inflammation of the rectum that occurs as a result of radiation therapy used to treat pelvic malignancies (prostate cancer, cervical cancer, etc.) and other diseases in the pelvic area or lower abdomen.^2,3,4 Radiation proctitis is broadly categorised into acute and chronic radiation proctitis, depending on the clinical manifestations and the onset of symptoms.^1,5,10

What is the difference between acute and chronic radiation proctitis?

Of patients who undergo radiation therapy, 75% develop acute proctitis, and up to 20% develop chronic proctitis.⁴ Acute and chronic proctitis can be distinguished based on the following criteria:

Onset: Acute proctitis typically manifests within three months of starting radiation therapy, whereas chronic proctitis develops months or even years after completing radiation therapy, typically after 9 to 14 months.^1,4 

Duration: Acute proctitis begins abruptly and usually resolves relatively quickly. It may, however, progress into chronic proctitis. In contrast, chronic proctitis can persist for an extended period or may present with intermittent symptoms.⁴                      

Symptoms: Acute proctitis symptoms include:^1,3,7

• Diarrhoea
• Nausea
• Mucus discharge from the anus
• Abdominal or pelvic pain
• Rectal urgency (a sudden and immediate need to have a bowel movement)
• Tenesmus (a persistent urge to have a bowel movement)
• Occult bleeding (blood not visible to the naked eye)¹²
• Pain with bowel movements⁸

These symptoms often resolve without treatment, especially after discontinuing radiation therapy. Chronic proctitis presents with similar symptoms to acute proctitis, with additional manifestations such as:^2,3,4 

• Severe rectal bleeding
• Ulcerations (sores on the inside lining of the rectum)⁴ 
• Rectal stricture (narrowing of the rectum)⁴ 
• Faecal incontinence (inability to control bowel movements)
• Fistula (an abnormal connection between different body parts, e.g., vagina and bladder)⁸
• Partial or complete rectal blockage, causing either diarrhoea or constipation

Why is it important to understand radiation proctitis?

Given that nearly half of the patients with pelvic malignancies are presumed to undergo radiation therapy, an increasing number of individuals are expected to present with symptoms of radiation proctitis. A thorough understanding of acute and chronic radiation proctitis is essential for enhancing patient care.³ Regular monitoring of high-risk patients, early intervention, and adopting a multidisciplinary approach are imperative for managing persistent symptoms and reducing the risk of more severe complications.⁵

How is radiation proctitis diagnosed?

A healthcare professional typically diagnoses radiation proctitis after reviewing the patient’s medical history, assessing the symptoms, and conducting a physical examination. A physician is also likely to suspect radiation proctitis in any patient who has previously received radiation therapy.⁶ 

To confirm radiation proctitis, various diagnostic procedures may be done. A proctoscopy may be performed to evaluate the rectum, and a sigmoidoscopy or colonoscopy may also be done to examine the lower part of the large intestine or the entire large intestine, respectively.²

It is essential to rule out other conditions, like inflammatory bowel disease (IBD) or infections before confirming the diagnosis. An abdominal ultrasound or CT scan can detect inflammatory bowel disease (IBD), and a stool test can confirm if the cause is infectious.⁶ Performing a biopsy of the inflamed rectal mucosa is generally not recommended, as it can exacerbate rectal bleeding and may contribute to the development of a fistula.³

What other health conditions cause similar symptoms as radiation proctitis?

The following are some of the conditions that may present with similar symptoms as radiation proctitis:⁵

• Inflammatory bowel disease (IBD)
• Crohn’s disease
• Infectious colitis
• Diverticulitis
• Cancer recurrence

What are the risk factors for radiation proctitis?

The following are some of the factors that increase the risk of developing radiation proctitis:^1,7,9

• Undergoing radiation therapy in the pelvic region or lower abdomen
• Receiving external beam radiotherapy¹⁰
• Receiving high-dose radiation
• Having inflammatory bowel disease (IBD) 
• Having acquired immunodeficiency syndrome (AIDS) or being HIV-positive 

How do you treat radiation proctitis?

Since presenting symptoms vary from patient to patient, treatment for radiation proctitis needs to be individualised with the help of a multidisciplinary team.

For acute proctitis patients

Supportive treatment comprising of hydration, enemas (corticosteroid or 5-ASA), and antidiarrheals is usually sufficient. Interrupting or stopping radiation therapy can help improve symptoms.³

For chronic proctitis patients

Treatment can be noninvasive or invasive, depending on the symptom severity.³ Noninvasive treatment includes anti-inflammatory agents (such as mesalamine or sulfasalazine),⁸ steroids (such as prednisone or betamethasone),³ antioxidants, sucralfate, short-chain fatty acids (SCFA), and hyperbaric oxygen therapy (HBO). Medications can be administered orally, as suppositories, or via enemas. Invasive options include ablation for destroying abnormal tissues or surgery for removing a damaged portion.^6,8

Symptom management³

1. Intermittent urgency, intermittent pain, occasional bleeding, moderate stricture, and superficial ulceration (>1 cm²):

Lifestyle modifications are necessary. (See below.)

2. Persistent urgency, persistent pain, persistent bleeding, severe stricture, and deep ulceration:

Hospital admission, minor surgery, and major lifestyle modifications are required.

3. Unresponsive rectal urgency, uncontrollable pain, severe blood loss, perforation, fistula, and complete rectal blockage:

Hospital admission and major surgery are necessary.

Patient education and lifestyle modifications

• Patients who have undergone radiation therapy for pelvic malignancy should be well-informed about the early signs and symptoms of radiation proctitis to remain vigilant and avoid any delay in seeking medical attention⁵
• Patients should be educated about lifestyle modifications and self-care practices that reduce the risk of developing radiation proctitis and improve rectal health.⁵ Patients should be encouraged to avoid or limit the intake of caffeine, sugars, alcohol, and tobacco, as this can help improve diarrhoea, thereby reducing rectal bleeding and pain. Similarly, incorporating fibre-rich foods, fibre supplements, or psyllium husk into the diet can help soften stools and ease constipation^5,6
• Regular medical check-ups are crucial for detecting and managing new complications promptly. Patients should also be cautioned about medical emergencies associated with radiation proctitis, such as excessive bleeding, dizziness, and weakness⁵

What is the prognosis of radiation proctitis?

The prognosis of radiation proctitis depends on the individual patient and their symptoms.⁵ Chronic radiation proctitis significantly affects the quality of life compared to acute radiation proctitis.³ Chronic proctitis patients may also experience persistent symptoms and difficult complications. Additionally, these patients are at risk of developing secondary colorectal cancers.⁵

What are the complications of radiation proctitis?

Following are some of the complications observed in patients with radiation proctitis:^4,5

• Iron deficiency anaemia (resulting from long-term rectal bleeding)⁸
• Radiation-induced malignancy
• Fistula (including rectovaginal, rectourethral, or rectovesical)³
• Abscess (a painful, swollen, pus-filled area)⁴ 
• Sepsis
• Bowel perforation
• Colitis

Bowel perforation and fistulas are two complications of radiation proctitis that require surgical intervention.

How do you prevent radiation proctitis?

Research has shown that patients who took selenium supplements during radiation therapy experienced a significant reduction in the severity of diarrhoea compared to those who did not.⁵

A correlation has been established between the amount of radiation therapy received and the severity of radiation proctitis symptoms. Therefore, proper planning of radiation therapy and adhering to the dose constraints can help reduce rectal and gastrointestinal (GI) toxicity.⁵

Utilising advanced radiation techniques such as intensity-modulated radiotherapy (IMRT) and image guidance can improve the delivery of radiation therapy by precisely targeting the tumour and minimising unnecessary exposure of adjacent healthy tissues.⁵

Similarly, during radiation therapy, it is important to create a physical space between the rectum and the target tissue. For example, injecting a gel into the fatty tissue surrounding the rectum enlarges the space between the front wall of the rectum and the back part of the prostate.⁵

Summary

Radiation proctitis is commonly observed in individuals who have undergone radiation therapy for pelvic malignancies such as prostate cancer and cervical cancer. Based on the onset time and clinical manifestations, radiation proctitis is classified into acute or chronic radiation proctitis.

Symptoms of radiation proctitis include abdominal pain, urgency, tenesmus, ulcerations, strictures, faecal incontinence, changes in stool consistency (diarrhoea or constipation), rectal bleeding, etc. The condition can be further complicated by fistulas, perforation, sepsis, and secondary colorectal malignancies.

Management of radiation proctitis usually takes a multidisciplinary approach, and the treatment options range from noninvasive to invasive, depending on the severity. Based on the presenting symptoms, medications like anti-inflammatory agents, antioxidants, steroids, or antidiarrheals may be prescribed. Patients should also be educated about the early signs and symptoms, lifestyle modifications, and dietary changes to improve their rectal health and overall quality of life.

During radiation therapy, measures should be taken to minimise the risk of developing radiation proctitis by adhering to dose constraints, targeting the tumour to reduce the unnecessary exposure of surrounding healthy tissues, and utilising advanced radiation techniques.

Overall, acute radiation proctitis has a good prognosis and is usually self-limiting. In contrast, chronic radiation proctitis can be complicated by more severe symptoms or secondary malignancies, necessitating careful management.