This study evaluated the efficacy of computed tomography (CT)-based three-dimensional (3D) dose-volume parameters ofthe rectum and urinary bladder as predictor for late complication in cervical cancer patients treated with radiotherapy.Forty-two patients treated with a combination of external radiotherapy and high-dose-rate intracavitary brachytherapy betweenJanuary 2002 and December 2008 were retrospectively analyzed. Brachytherapy was prescribed with standard 2D planning.Patients underwent pelvic CT at every brachytherapy. The external rectal wall and bladder wall were contoured on the CTimages, and the minimum doses delivered to 0.1 cc, 1 cc, 2 cc and 5 cc of the most irradiated rectal and bladder volumes werecalculated with dose-volume histograms. Total dose (external radiotherapy plus brachytherapy) to the rectum and the urinarybladder was transformed to the biologically equivalent dose in 2 Gy fractions with / of 3 Gy (D0.1cc, D1cc, D2cc andD5cc). The relationships between these dosimetric parameters and the incidence of late rectal complication (LRC) wereanalyzed. The values of D0.1cc, D1cc, and D2cc were significantly higher in patients with LRC than in those without (p <0.05), but the difference in the values of D5cc was not statistically significant (p = 0.092). The rate of LRC is increasedsignificantly with rectal D1cc higher than 90 GyEQD2 (p = 0.010). This study has suggested that CT-based 3D dose- volumeparameters of the rectum may be effective for predicting LRC
