Correlation between urinary dose and delayed radiation cystitis after 78 Gy intensity-modulated radiotherapy for high-risk prostate cancer: A 10-year follow-up study of genitourinary toxicity in clinical practice. (October 2017)

• Record Type: Journal Article
• Authors: Inokuchi, Haruo; Mizowaki, Takashi; Norihisa, Yoshiki; Takayama, Kenji; Ikeda, Itaru; Nakamura, Kiyonao; Hiraoka, Masahiro
• Is Part Of: Clinical and translational radiation oncology. Volume 6(2017)
• Page Start: 31
• Page End: 36
• Publication Date: 2017-10
• Subjects: Intensity-modulated radiation therapy -- Prostate cancer -- GU toxicity -- Long term follow-up -- Urinary dose; Cancer -- Radiotherapy -- Periodicals; Oncology -- Periodicals; Cancer -- Radiotherapy; Oncology; Radiation Oncology; Neoplasms -- radiotherapy; Translational Medical Research; Periodicals; Electronic journals; Periodicals; 616.9940642
• DOI: 10.1016/j.ctro.2017.09.005
• Languages: English
• ISSNs: 2405-6308

Abstract

Highlights: High-dose prostate IMRT was well tolerated in terms of long-term GU toxicities. Hematuria was the most common long-term GU toxicity after high-dose IMRT. Bladder neck dose–volume data were significantly associated with hematuria. Abstract: Purpose: To investigate the factors associated with the risk of long-term genitourinary (GU) toxicity among high-risk prostate cancer (PC) patients treated with high-dose intensity-modulated radiotherapy (IMRT). Methods and materials: Between 2000 and 2011, PC patients treated with 78 Gy in 39 fractions delivered by IMRT combined with neo-adjuvant hormonal therapy were selected from among our database. GU toxicities and clinical factors, as well as separate anatomical urinary structures, were evaluated in terms of their associations. Results: A total of 309 patients was included in this study. The median follow-up was 104 months (range: 24–143 months). The most frequently observed late grade ≥2 GU toxicity was hematuria (11.2%: 10-year actuarial risk) with radiation cystitis observed in the majority of patients. In univariate analysis, late grade ≥2 hematuria was associated with the exposure to doses >75 Gy (V75) of the bladder neck and V70 of the bladder wall, as well as with T stage. V75 of the bladder neck remained significant in multivariate analysis ( p = 0.049). Conclusions: At the 10-year follow up of high-dose IMRT, a major concern was proved to be delayed cystitis related to the higher volume of bladder neck dose exposed excess over 75 Gy.