Radiation proctitis is a frequent acute complication encountered with pelvic irradiation. This study was aimed at establishing the optimal radiation dose for radiation-induced proctitis in rats. Female Wistar rats were used. The rectal specimens were examined morphologically at 5th and 10th day following 10-30 Gy irradiation in single fraction. With increasing dose, mucosal damage became worse, and there was a prominent reaction after > or =15 Gy. We selected 17.5 Gy as an optimal dose for radiation proctitis and examined specimens at day 1-14 and at week 4, 6, 8, and 12 after 17.5 Gy. The rectal mucosa revealed characteristic histological changes with time. An edema in lamina propria started as early as 1-2 days after irradiation and progressed into acute inflammation. On day 7 and 8, regeneration was observed with or without ulcer. Four weeks later, all regeneration processes have been completed with end result of either fibrosis or normal appearing mucosa. This study showed that the radiation injury of the rectum in rat develops in dose-dependent manner as it has reported in previous studies and suggested that 17.5 Gy in single fraction is the optimum dose to evaluate the protective effect of various medications for radiation proctitis in face of the clinical situation.
Animal ; Disease Models, Animal ; Dose-Response Relationship, Radiation ; Female ; Proctitis*/pathology ; Proctitis*/mortality ; Proctitis*/etiology ; Rats ; Rats, Wistar ; Rectum/radiation effects* ; Rectum/pathology ; Time Factors

Hemorrhagic radiation proctitis is infrequently seen in patients receiving pelvic irradiation. The treatment of hemorrhagic ralation proctitis is often difficult. Many patients need reyeated hospitalizations and blood transfusions. Occasionally patiets will develop severe or recurrent rectal bleeding. In case of massive bleeding requiring excessive transfusion, colonic diversion by construction of a colostomy or excision of the diseased segment may be inevitable. However, surgical procedures in these patients are associated with a high mortality and morbidity. Moreover, medical therapy is usually ineffective. Recently formalin therapy has been introduced as a simple and effective treatment for hemorrhagic radiation proctitis. We experienced a 69 year-old woman patient who developed severe homorrhagic proctitis 1 year after radiotherapy for carcinoma of the cervix. She had not improved by conservative management and required blood tranafusions and repetitive hospitalizations. After local application of a 4% formalin solution in the diseased rectum under caudal anesthesia, the bleeding immediately stopped and the patient was discharged from the hospital, and no recurrence has been observed until now.
Aged ; Anesthesia, Caudal ; Blood Transfusion ; Cervix Uteri ; Colon ; Colostomy ; Female ; Formaldehyde* ; Hemorrhage ; Hospitalization ; Humans ; Mortality ; Proctitis* ; Radiotherapy ; Rectum ; Recurrence