Treatment outcome of high-dose image-guided
intensity-modulated radiotherapy using intraprostate
fiducial markers for localized prostate
cancer at a single institute in Japan
Several studies have confirmed the advantages of delivering high doses of external beamradiotherapy to achieve optimal tumor-control outcomes in patients with localized prostatecancer. We evaluated the medium-term treatment outcome after high-dose, image-guidedintensity-modulated radiotherapy (IMRT) using intra-prostate fiducial markers for clinicallylocalized prostate cancer.
In total, 141 patients with localized prostate cancer treated with image-guided IMRT (76Gyin 13 patients and 80Gy in 128 patients) between 2003 and 2008 were enrolled in this study.The patients were classified according to the National Comprehensive Cancer Networkdefinedrisk groups.
Thirty-six intermediate-risk patients and 105 high-risk patients wereincluded. Androgen-deprivation therapy was performed in 124 patients (88%) for a median of11months (range: 2-88 months).
Prostate-specific antigen (PSA) relapse was definedaccording to the Phoenix-definition (i.e ., an absolute nadir plus 2 ng/ml dated at the call). The5-year actuarial PSA relapse-free survival, the 5-year distant metastasis-free survival, the 5-year cause-specific survival (CSS), the 5-year overall survival (OS) outcomes and the acuteand late toxicities were analyzed.
The toxicity data were scored according to the CommonTerminology Criteria for Adverse Events, version 4.0. The median follow-up was 60 months.
The 5-year PSA relapse-free survival rates were 100% for the intermediate-risk patients and82.2% for the high-risk patients; the 5-year actuarial distant metastasis-free survival rateswere 100% and 95% for the intermediate- and high-risk patients, respectively; the 5-year CSSrates were 100% for both patient subsets; and the 5-year OS rates were 100% and 91.7% forthe intermediate- and high-risk patients, respectively.
The Gleason score (<8 vs. [greater than or equal to]8) wassignificant for the 5-year PSA relapse-free survival on multivariate analysis (p=0.044).
Therewas no grade 3 or 4 acute toxicity. The incidence of grade 2 acute gastrointestinal (GI) andgenitourinary (GU) toxicities were 1.4% and 8.5%, respectively.
The 5-year actuariallikelihood of late grade 2-3 GI and GU toxicities were 6% and 6.3%, respectively. No grade4 GI or GU late toxicity was observed.
These medium-term results demonstrate a good tolerance of high-dose image-guided IMRT.However, further follow-up is needed to confirm the long-term treatment outcomes.
Published on: 2012-07-06