title: Prediction of toxicities of prostate cancer radiotherapy.
abstract: We treated a cohort of 116 patients with prostate cancer with three-dimensional conformal hypofractionated radiotherapy to a total dose of 52.8 Gy in 16 fractions (3.3 Gy per fraction). The correlation between acute and late gastrointestinal (GI) and genitourinary (GU) toxicity and dose-volume parameters was analysed. Comparison of observed incidence of toxicity and normal tissue complication probability calculated from dose-volume histograms (DVH) of all patients using radiobiological Lyman-Kutcher-Burman model was performed. The results of our study suggest that acute gastrointestinal toxicity ≥ grade 2 (G2) is the significant predictor of late toxicity ≥ G2 (p=0.006). Observed incidence of acute and late GI toxicities ≥ G2 was 9.7% and 11.5%, respectively. NTCPs of acute and late GI complications ≥ G2 were 11.3% and 2.5%. Observed incidence of late GU toxicity ≥ G2 was 14.2%, NTCP was 0.8%. Comparison of calculated probability of acute GI toxicity ≥ G2 and observed incidence indicates that parameters of radiobiological models are set appropriately. Comparison of observed incidence of late GI and GU complications ≥ G2 and calculated NTCPs shows the need of refinement of LKB model parameters for acute and late GI and GU complications ≥ G2.
  
  
  
  prostate cancer, radiotherapy, acute and late toxicity, radiobiological modeling.
authors.forename: B
authors.initials: B
authors.lastname: Hostova
authors.forename: P
authors.initials: P
authors.lastname: Matula
authors.forename: P
authors.initials: P
authors.lastname: Dubinsky
mesh_terms: D004307:Dose-Response Relationship, Radiation; D005544:Forecasting; D041981:Gastrointestinal Tract / Q000528:radiation effects*; D006801:Humans; D008297:Male; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D011832:Radiation Injuries; D050397:Radiotherapy, Intensity-Modulated / Q000009:adverse effects*; D014551:Urinary Tract / Q000528:radiation effects*