Radiation injury of the rectum.

Any clinician involved in the treatment of pelvic malignancies with radiation is aware of the potential for rectal injury. Although severe effects have been well described for many years, it is only more recently that lesser degrees of rectal injury have been considered important. Patients are not always forthcoming in describing symptoms they find socially embarrassing; clinicians perhaps reticent in pursuing symptoms that may be resistant to intervention; and preclinical and clinical researchers handicapped by difficulty accessing the organ. Endpoints used in animal models may not reflect those of importance in humans. Interest in rectal injury has been stimulated by advances in brachytherapy technology and the advent of conformal therapy for prostate cancer. More sophisticated clinical assessments of late toxicity have evolved and greater efforts made to understand the pathophysiology of patients symptoms. This review aims to draw together pre-clinical and clinical information pertaining to rectal injury due to radiation. It is not intended as an exhaustive review of the incidence of rectal injury, but more detail has been provided on the impact of treatment of prostate and cervix cancer, particularly when patient-derived endpoints have been used.