ABSTRACT
Radiation injury to the gastrointestinal tract was first described in 1897, two years after the discovery of X-rays by Wilhelm Roentgen (1). Subsequently, although ionizing radiation was found to be an effective treatment of breast, skin, and other detectable malignancies it was limited by the complications of skin burns and hyperemia. Supervoltage radiation techniques allow the utilization of high radiation doses for the treatment of neoplasms without skin complications; unfortunately, radiation-induced deep tissue damage has become a significant problem with its use. Radiation injury to the colon may be concomitant with small bowel injury. It is seen most often with irradiation of pelvic malignancies: prostate, cervix, uterus, bladder, colon, rectum, and ovaries. During the last 25 years, in spite of improved knowledge and technical advancements in computer-aided dosimetric analysis, brachytherapy, megavoltage equipment, radioprotective techniques and compounds, the prevalence of radiation-induced gastrointestinal injury is estimated to be between 2% and 20% (2-7). However, these estimates are based on retrospective studies comprised of small groups of heterogeneous patients with a wide variety of primary malignancies treated, radiotherapy techniques used, radiation injury locations and severity, and duration of follow-up. The use of radiation in up to 50% of cancer treatment (1), and the increased availability of chemotherapy agents that may sensitize the colon to radiation has made colonic injury from radiation a significant and persistent problem. Moreover, the rectum’s proximity to the organs that are common targets for radiation therapy, as well as its susceptibility to significant chronic radiation injury in the setting of few proven therapeutic options has made radiation proctopathy a difficult clinical entity for managing physicians. This chapter discusses the epidemiology, pathology, pathogenesis, clinical features and treatment options along with the prognosis and future direction of radiation-induced colorectal injury. In this chapter, data on rectal injury (proctopathy) will be separated from injury to other parts of the colon (colopathy) to reflect the two main bodies of literature on colonic radiation injury.
