Abstract
PurposeProstate cancer (PCA) is highly heterogeneous in terms of its oncologic outcome. We therefore aimed to tailor radiation treatment to the risk status by using three different hypofractionated radiation regimen differing in applied dose, use of rectum spacer, inclusion of pelvic lymph nodes (pLN) and use of androgen deprivation therapy (ADT). Here we report on acute toxicity, quality of life (QOL) and oncologic outcome at a median follow-up of 12 months.MethodsA total of 221 consecutive PCA patients received hypofractionated intensity-modulated radiotherapy (IMRT). Low-risk (LR) patients were planned to receive 60 Gy in 20 fractions (EQD2α/β1.5 = 77.1 Gy), intermediate-risk (IR) patients 63 Gy in 21 fractions (EQD2α/β1.5 = 81 Gy), and high-risk (HR) patients 67.5 Gy in 25 fractions (EQD2α/β1.5 = 81 Gy) to the prostate and 50 Gy in 25 fractions to the pLN. Acute rectal toxicity was assessed by endoscopy. In addition, toxicity was scored using CTC-AE 4.0 and IPSS score, while QOL was assessed using QLQ-PR25 questionnaires.ResultsAcute CTC reactions were slightly higher in the HR regimen but reverted to baseline at 3 months. GI G2 toxicity was 4%, 0% and 12% for the LR, IR and HR regimen. Compared to IR patients, the increase in toxicity in HR patients was statistically significant (p = 0.002) and mainly caused by a higher incidence of diarrhea presumably due to pelvic EBRT. QOL scores of all domains were worse for the HR regimen (not significant).ConclusionRisk-adapted moderate hypofractionation is associated with low GI/GU toxicity. Given the higher rate of pelvic metastases in HR patients, slightly higher transient acute reactions should be outweighed by possible oncological benefits.
Highlights
The prognosis of prostate cancer is highly dependent on its risk profile as developed by D’Amico et al [1] and adopted by the RTOG and AUA
We have compared toxicity profiles of three different hypofractionation schedules which were designed under the assumption that HR prostate cancer requires escalated treatment compared to LR prostate cancer which holds a high risk of overtreatment
Treatment differed in applied dose, use of rectal spacers, use of antihormonal medication and inclusion of pelvic lymph nodes (pLN)
Summary
From February 2015 to July 2018, 221 patients referred for primary radiotherapy were eligible to receive risk adapted hypofractionated radiation treatment (Table 3 for patient characteristics). 4.0 scores (Fig. 1c, d): Acute GU G1 toxicity was 58%, 64% and 51% for LR, IR and HR regimen at the end of RT and returned to baseline levels at 3 months. Acute GI G1 toxicity at end of RT was 21%, 18% and 33% for LR, IR and HR, respectively, and reverted to near baseline levels at 3 months. By the end of therapy, the urinary score increased to a comparable extent in all regimen groups (27.1) but reverted to baseline at 6 months after the end of therapy. This is in good concordance with the acute toxicity assessment which showed very similar dynamics. Biochemical progression-free survival at a median followup of 12 months was 99% overall, and 100%, 100% and 97% for LR, IR and HR patients, respectively
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