A 63-year-old man comes to the physician with a 4-week history of rectal pain and occasional rectal bleeding. He initially thought he had hemorrhoids and applied over-the-counter creams without significant relief. He had prostate cancer treated with external beam radiation therapy 1 year earlier. The patient is an ex-smoker with a 30-pack-year history but does not use alcohol or illicit drugs. He lives with his girlfriend of 10 years.
His blood pressure is 128/68 mm Hg, pulse is 76/min, and respirations are 14/min. Cardiopulmonary examination is normal. The abdomen is soft and nontender to palpation. Rectal examination reveals guaiac- positive brown stool.
Laboratory results are as follows:

Sigmoidoscopy shows rectal mucosal pallor with friability and several telangiectasias.
Which of the following is the most likely cause of this patient's condition?

Question

A 63-year-old man comes to the physician with a 4-week history of rectal pain and occasional rectal bleeding.  He initially thought he had hemorrhoids and applied over-the-counter creams without significant relief.  He had prostate cancer treated with external beam radiation therapy 1 year earlier.  The patient is an ex-smoker with a 30-pack-year history but does not use alcohol or illicit drugs.  He lives with his girlfriend of 10 years.
His blood pressure is 128/68 mm Hg, pulse is 76/min, and respirations are 14/min.  Cardiopulmonary examination is normal.  The abdomen is soft and nontender to palpation.  Rectal examination reveals guaiac- positive brown stool.
Laboratory results are as follows:

Sigmoidoscopy shows rectal mucosal pallor with friability and several telangiectasias.
Which of the following is the most likely cause of this patient's condition?

Quizplus · Accepted Answer

This patient with a history of prostate cancer and radiation therapy likely has radiation proctitis. Radiation injury most commonly affects the rectosigmoid colon and occurs following treatment of lower gastrointestinal (eg, anus, rectum) or genitourinary (eg, cervix, prostate) malignancies. Prostate cancer treatment is the most common reason for radiation injury to the rectum due to the higher doses used compared with other malignancies. Both acute and chronic radiation injuries can occur and differ in time from radiation and type of symptoms. Acute radiation proctitis occurs during or within 6 weeks of radiation therapy. Symptoms include diarrhea, tenesmus, and, rarely, bleeding. They usually resolve once radiation is stopped but can continue for up to 1 year after treatment discontinuation. Chronic radiation proctitis occurs much later, often 9-12 months (sometimes longer) after radiation therapy. It is caused by intestinal epithelial atrophy and fibrosis accompanied by mucosal ischemia, often leading to stricture formation and bleeding. Clinical features of chronic radiation proctitis include diarrhea, fecal obstruction, bleeding, tenesmus, and fecal incontinence. Injury to the genitourinary tract or small bowel can lead to complications such as fistula formation, small bowel obstruction, and cystitis. There is also an increased risk of secondary malignancy (eg, colorectal cancer) in patients exposed to radiation. Diagnosis can be confirmed with sigmoidoscopy or colonoscopy, which may reveal large, continuous areas of mucosal pallor with friability and telangiectasias. Rectal biopsies, if needed, should be performed judiciously due to the risk of fistula formation. Treatment of acute radiation proctitis includes butyrate enemas to promote rapid healing. Mild bleeding due to chronic radiation proctitis does not require treatment. Other therapies for chronic radiation proctitis depend on the severity of symptoms and include sucralfate enemas, stool softeners, endoscopic therapy, and surgery for patients with intractable symptoms (eg, bleeding, pain). (Choice A) Androgen deprivation therapy is used for metastatic prostate cancer. It has many side effects, including fatigue, sexual dysfunction, osteoporosis and fractures, hot flashes, anemia, gynecomastia, and an increased risk of cardiovascular disease and diabetes. However, proctitis is not a side effect of androgen deprivation therapy. (Choice B) Collagenous colitis results in chronic, intermittent, watery diarrhea without bleeding and is accompanied by fecal urgency. Colonoscopy reveals normal colon, but biopsy shows inflammation (colitis) without mucosal ulcerations. (Choice C) Human papillomavirus infection is highly associated with anal squamous cell carcinoma. Condyloma acuminata predisposes individuals to anogenital cancers and is usually evident on visual inspection of the genitourinary area. (Choice D) Ulcerative colitis and radiation proctitis may appear similar on colonoscopy (irregular, friable, and erythematous mucosa with ulceration). However, radiation proctitis is the most likely diagnosis in patients with a history of radiation treatment. Similarly, Crohn's disease usually has a cobblestoning pattern and discontinuous lesions that differentiate it from radiation proctitis. The rectum is not always involved in Crohn's disease. Educational objective: Prostate cancer treatment is the most common reason for radiation injury to the rectum. Acute radiation proctitis can occur during or within 6 weeks of radiation therapy. Chronic radiation proctitis occurs 9-12 months after therapy. Diagnosis is made via sigmoidoscopy, which reveals large, continuous areas of mucosal pallor with friability and telangiectasias. __________ References: Management of intestinal complications in patients with pelvic radiation disease. (http://www.ncbi.nlm.nih.gov/pubmed/22858731)

A 63-Year-Old Man Comes to the Physician with a 4-Week