The 5-year outcomes of moderately hypofractionated radiotherapy (66 Gy in 22 fractions, 3 fractions per week) for localized prostate cancer: a retrospective study
Hypofractionated radiotherapy using fewer and larger fractional doses may be more beneficial than conventional external-beam radiotherapy for localized prostate cancer. We evaluated the 5-year outcomes of moderately hypofractionated radiotherapy for localized prostate cancer.
We retrospectively evaluated 195 patients with localized prostate cancer (T1–3N0M0) who underwent intensity-modulated radiotherapy (IMRT) (66 Gy delivered in fractions of 3 Gy every other weekday) between May 2005 and December 2011. Patients received androgen deprivation therapy depending on the perceived intermediate or high risk of their disease. A prostate-specific antigen nadir +2.0 ng/ml indicated biochemical failure. We assessed toxicity using the Radiation Therapy Oncology Group and the European Organization for Research and Treatment of Cancer (RTOG/EORTC) criteria, and patient-reported outcomes using the Expanded Prostate Cancer Index Composite (EPIC).
The risk classifications (proportion) were low risk (13.8%), intermediate risk (35.9%), and high risk (50.3%). The median follow-up was 69 months. Thirteen (6.66%) patients experienced biochemical failure within a median of 40 months (interquartile range, 25–72 months). The 5-year overall survival rate and no biological evidence of disease rate were 97.7% and 92.4%, respectively. Based on the RTOG/EORTC criteria, no patient experienced acute or late toxicity of grade 3 or higher. The EPIC scores revealed significant differences in the average value of all domains (p < 0.01). At 1 month postradiotherapy completion, the general urinary and bowel domain scores had decreased, but these scores returned to baseline level by 3 months post radiotherapy.
The moderately hypofractionated radiotherapy protocol yielded short-term satisfactory clinical outcomes with acceptable toxicity.
KeywordsHypofractionation Intensity-modulated radiotherapy Patient-reported outcome Prostate cancer Prostate-specific antigen Quality of life
Androgen deprivation therapy
Analysis of variance
Biologically effective dose
No biochemical evidence of disease
Conventional or hypofractionated high-dose intensity-modulated radiotherapy for prostate cancer
Common terminology criteria for adverse events
European Organization for Research and Treatment of Cancer
Expanded Prostate Cancer Index Composite
HYpofractionated irradiation for PROstate cancer
Overall treatment time
PROstate fractionated irradiation trial
Quality of life
Radiation Therapy Oncology Group
Editage (www.editage.jp) provided English language editing for this manuscript.
All authors have read and approved the final manuscript.
Compliance with ethical standards
Ethics approval and consent to participate
The protocol of this study was approved by the institutional review board of Tokyo Women’s Medical University in Tokyo, Japan (protocol number 637). All participants provided informed consent.
Conflict of interest
No author has any conflict of interest.
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