title: Statistical analysis of dose-volume and dose-wall histograms for rectal toxicity following 3D-CRT in prostate cancer.
abstract: The purpose of this paper is to determine the correlation between dose-volume histogram (DVH) and dose wall-histogram (DWH) in the evaluation of rectal complications for prostate cancer patients treated with three-dimensional conformal radiotherapy (3D-CRT). A retrospective analysis of DVHs and DWHs of a subset of 25 prostate cancer patients treated with 3D-CRT was performed. For every patient the rectum and the rectal wall (inner and outer surface) were contoured. Median ICRU radiation dose of 79.4 Gy was administered. Correlation between DVHs and DWHs parameters was investigated by the nonparametric Spearman test and by linear regression analysis. The results showed a statistically significant linear correlation between pairs of DVH and DWH dosimetric parameters with Spearman correlation values (S) bigger than 0.8, with p values better than 0.0005 (two-sided) when the emptied rectum is considered. The variation of S and linear fit slope values [b(1)] showed a very similar functional shape with a minimum at 91% ICRU dose [S =0.83, b(1)=0.65]. The present study confirms a high correlation (>80%) between DVH and DWH of the rectum following 3D-CRT for prostate cancer. The derived advantage is that the contouring of inner surface of rectum could be obviated in almost 90% of patients when performing predictive models for rectal complications based on dosimetric variables under the standard treatment conditions specified in this study.
authors.affiliation: Department of Medical Physics, Hospital Universitario de la Princesa, Madrid, Spain. fgarcia.hlpr@salud.madrid.org
authors.forename: Feliciano
authors.initials: F
authors.lastname: García-Vicente
authors.forename: Almudena
authors.initials: A
authors.lastname: Zapatero
authors.forename: Alejandro
authors.initials: A
authors.lastname: Floriano
authors.forename: Alfonso
authors.initials: A
authors.lastname: Cruz-Conde
authors.forename: Leopoldo
authors.initials: L
authors.lastname: Perez
authors.forename: Alicia
authors.initials: A
authors.lastname: Marín
authors.forename: Cristina
authors.initials: C
authors.lastname: Mínguez
authors.forename: Juan J
authors.initials: JJ
authors.lastname: Torres
mesh_terms: D001822:Body Burden; D003198:Computer Simulation; D003627:Data Interpretation, Statistical; D004307:Dose-Response Relationship, Radiation; D006801:Humans; D008297:Male; D008954:Models, Biological; D015233:Models, Statistical; D009928:Organ Specificity; D011471:Prostatic Neoplasms / Q000150:complications / Q000532:radiotherapy*; D011832:Radiation Injuries / Q000209:etiology* / Q000517:prevention & control; D011874:Radiometry / Q000379:methods*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D020266:Radiotherapy, Conformal / Q000009:adverse effects* / Q000379:methods; D012002:Rectal Diseases / Q000209:etiology* / Q000503:physiopathology; D012062:Relative Biological Effectiveness; D012189:Retrospective Studies; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors