Radiation proctocolitis

Background

• Injury to the colon following radiation therapy most commonly affecting the sigmoid colon and rectum.
• 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.
• Occurs up to 6 weeks after receiving radiation therapy

Clinical Features

Uncomplicated

• Diarrhea
• Urgency
• Mucus discharge
• Tenesmus
• 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

• Ulcerative colitis
• Crohns disease
• Inflammatory Bowel Disease
• CMV Colitis
• Infectious/parasitic enterocolitis
• Diversion colitis
• Ischemic colitis
• Diverticular colitis
• Chronis graft-versus-host diease

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
  • Telangiectatic
  • Avoid this procedure in severe proctitis as it may facilitate fistula 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.

Chronic

• Non-invasive
  • anti-inflammatories
  • sucralfate
  • short-chain fatty acids
  • Hyperbaric O2
  • Antioxidants
• Invasive
  • ablation surgery
  • Resection if localized

Disposition

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