Radiation proctocolitis

Background

• Injury to the colon following radiation therapy most commonly affecting the sigmoid colon and rectum.
• Acute ( up to three months), Chronic ( 3 months to years later)
• Results in majority from radiation to the lower abdomen and pelvis as in the cases of cancers of the rectum, colon, gonads, uterus, bladder, and prostate.

Clinical Features

Uncomplicated

• Diarrhea
• Urgency
• Mucus discharge
• Tenesmus
• GI bleeding is more common in chronic radiation proctitis than acute radiation proctitis

Complicated

• Radiation injury extending to genitourinary system
  • urethral stenosis
  • Cystitis
  • Ureteral scarring
• Radiation injury extending to small bowel
  • Small bowel obstruction
  • Small intestine bacterial overgrowth
  • Fistulae

Differential Diagnosis

• Inflammatory bowel disease
• Infectious colitis
• Diversion colitis
• Ischemic colitis
• Diverticulitis
• Chronic graft-versus-host disease

Evaluation

• Labs
  • Stool C.diff toxin along with routine stool cultures
  • Specific testing for E.coli 0157:H7
  • Ova and Parasite assay including giardia
  • CBC, electrolytes, albumin, ESR, CRP

• Endoscopy and biopsy
  • Nonspecific findings
  • Pallor, friability, ulcerations, bleeding
  • Telangiectatic with bleeding
  • Avoid biopsy unless malignancy is suspected as facilitate fistula/non healing wound formation

• Imaging
  • CT if obstructive symptoms are present
  • MRI if suspicion is high for radiation-induced fistulae

Management

Acute

• Generally self-limited
• approximately 20% of patients will need to lengthen time intervals between radiation therapy to recover
• Hydration, steroids, +/- 5-aminosalicylate enema, bowel regimen.

Chronic

• Non-invasive
  • Anti-inflammatories
  • Sucralfate enema
  • short-chain fatty acids
  • Hyperbaric O2
  • Antioxidants: Vitamin A, E, C.
• Invasive
  • Endoscopic treatment with ablation therapy : Topical formalin, Laser, Argon plasma coagulation
  • Surgical resection last resort

Disposition

• Treat outpatient
• Severe cases that are candidates for surgery should be admitted