PURPOSE: To develop a method for investigating local dose effects on the bladder after prostate cancer radiotherapy based on dose-surface maps (DSMs). BACKGROUND AND PURPOSE: DSMs of patients included in a prospective study (DUE01) were generated by virtually cutting bladder contours at the points intersecting the sagittal plane passing through its center-of-mass: maps were laterally normalized and aligned at the posterior inferior point. The average DSMs of patients with/without toxicity, the DSMs of differences and t statistic were used to select regions better discriminating patients with toxicity. A total of 72 patients with no/mild urinary symptoms before radiotherapy and who were treated with moderate hypo-fractionation (2.5-2.65Gy/fr, 70-74Gy) were considered, and the endpoint was an International Prostate Symptoms Score (IPSS)⩾15 at the end of therapy (IPSSend⩾15, n=25/72). RESULTS: The DSMs of patients with/without toxicity were significantly different (p<0.05). The percentage of bladder circumference receiving >50-70Gy at 5-7mm from the base was associated with an IPSSend⩾15 (odds ratios: 1.03-1.07). Different patterns were recognized for specific symptoms. With frequency/urgency, a quasi-threshold effect on the absolute posterior dose at 5-12mm from the base (2Gy equivalent doses=80-82Gy, α/β=3-5Gy) was observed. CONCLUSIONS: Local-dose effects for acute symptoms were detected in a group of patients treated within a moderately hypo-fractionated protocol. The results for frequency/urgency were consistent with a threshold effect on the trigone.
First application of a pixel-wise analysis on bladder dose-surface maps in prostate cancer radiotherapy / F. Palorini, C. Cozzarino, S. Gianolini, A. Botti, V. Carillo, C. Iotti, T. Rancati, R. Valdagni, C. Fiorino. - In: RADIOTHERAPY AND ONCOLOGY. - ISSN 0167-8140. - 119:1(2016), pp. 123-128.
|Titolo:||First application of a pixel-wise analysis on bladder dose-surface maps in prostate cancer radiotherapy|
|Parole Chiave:||Dose-volume effects; Prostate cancer; Radiotherapy; Urinary toxicity; Hematology; Oncology; Radiology, Nuclear Medicine and Imaging|
|Settore Scientifico Disciplinare:||Settore MED/36 - Diagnostica per Immagini e Radioterapia|
|Data di pubblicazione:||2016|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1016/j.radonc.2016.02.025|
|Appare nelle tipologie:||01 - Articolo su periodico|