Guidelines for Complications of Cancer Treatment Vol VIII Part B

sigmoid colon and rectum being in close proximity to thetumour will be affected the most. Similarly, in postoperativecases and in extended field treatments including para-aorticnodes, a sizeable amount of small bowel tends to get irradiated.The intestines are an important dose-limiting organ inabdomino-pelvic radiotherapy.Severity and frequency of gut toxicity depends on total dose,fractionation, volume of bowel irradiated, concurrentadministration of chemotherapy and co-morbidities like pelvicinflammatory disease, hypertension, inflammatory boweldisease, HIV infection and thin body habitus. For instance,the incidence of severe late toxicity in women treated forcervical cancer was 10 - 15% at 20 years with a 30-40%incidence of chronic diarrhea, and a late small bowelobstruction of 9-30% requiring surgery at 5-years.Acute bowel toxicity manifests clinically as enteritis andulceration in the intestine with loss of epithelial integrity andincreased secretion of mucus. Patients manifest with chronicdiarrhea with resultant tissue edema and hyperemia. Thesesymptoms may be severe enough to require an alteration inthe treatment plan, they are usually transient and cease shortlyafter completion of radiation therapy.Delayed intestinal dysfunction may continue to worsen intothe late stage effects, typically presenting 6 months to 3 yearsafter radiation therapy. In a retrospective study by Olopadeet al., 90% of patients undergoing pelvic radiation reported apermanent change in their bowel habit after treatment, withnearly 50% reporting adverse effects on quality of lifemeasures.Diagnosis, Prevention and ManagementDiagnostic tests used in the workup of patients with recurrentabdominal symptoms post radiation therapy includes imaging,267