Radiation Proctitis

Radiation proctitis is inflammation of the rectum that occurs as a result of damage to the rectum sustained from pelvic radiation given to treat a cancer such as prostate or cervical cancer. Radiation proctitis can be acute or chronic depending on the timing relative to the radiation therapy.

What causes acute radiation proctitis?
Acute radiation proctitis presents either during or up to 6 months after completion of radiation therapy. Acute radiation proctitis is essentially collateral damage from the oxygen-free radicals created by the radiation therapy itself.  One in five patients with acute radiation proctitis may require temporary cessation of therapy until the symptoms resolve.  Fortunately, once the acute radiation proctitis has resolved, the majority of patients remain symptom-free and do not go on to develop chronic radiation proctitis.

What are the symptoms of acute radiation proctitis?
The symptoms of Acute Radiation Proctitis include:

-Diarrhea (with or without blood)

-Nausea

-Abdominal cramping

-Tenesmus (a sensation of urgency to have a bowel movement, sometimes even when there is no bowel movement to pass)

-Mucoid discharge

What causes chronic radiation proctitis?
Chronic radiation proctitis can develop in up to 20% of patients who have received pelvic radiation.  The nature and severity of the symptoms are determined by the location and of course, the severity of radiation injury.  In contrast to acute radiation proctitis, chronic radiation proctitis can manifest anytime following completion of radiation therapy from 6 months to 30 years. It results from generalized tissue fibrosis, narrowing of arterioles and development of telangectasias (abnormal blood vessels that can bleed easily) due to radiation.

What are the symptoms of chronic radiation proctitis?
The symptoms of Chronic Radiation Proctitis include:

-Rectal bleeding (most common).

-Development of a recto-vaginal fistula in women

-Development of recto-urethral fistula in men

-Rectal pain

-Partial or complete obstruction of the rectum resulting in either

-Diarrhea or

-Constipation

-Fecal incontinence

How is chronic radiation proctitis diagnosed?
An in-office history and examination by a colon and rectal surgeon will generally allow proper diagnosis of chronic radiation proctitis, along with evaluation of the rectum, either with a flexible or rigid proctoscope. If a colonoscopy has not been done, then a colonoscopy will be advised.

What is the treatment of radiation proctitis?
In the event of fistula formation or obstruction, surgery with removal of the affected segment of bowel is necessary.  If a patient has intractable symptoms of rectal bleeding or pain, creation of a colostomy may be indicated.  Once done, the pain and bleeding will typically subside.

Prior to creation of a colostomy, other non-operative interventions should be attempted. Rectal bleeding is the most common manifestation of chronic radiation proctitis. Argon Plasma Coagulation, or APC, is an intervention that is performed with an endoscope. It is highly effective at relieving bleeding but may require more than one round of therapy. The argon is used to coagulate the thinned blood vessels, called telangectasias.  Additional possible interventions include application of formalin to the rectal lining. This can be performed either in the operating room or in an office setting.

What is the prognosis of radiation proctitis?
Pelvic radiation therapy is associated with an increased rate of rectal cancer. The latency period between radiation exposure and development of a radiation-induced cancer is felt to be at least 5 years. For this reason it is important for anyone who has received pelvic radiation to have either a colonoscopy or a flexible sigmoidoscopy starting 5 years after completion of radiation therapy.