Ultrahypofractionated radiotherapy for localized prostate cancer with simultaneous boost to the dominant intraprostatic lesion: a plan comparison

2021 ◽  
pp. 030089162110116
Author(s):  
Raffaella Cambria ◽  
Delia Ciardo ◽  
Alessia Bazani ◽  
Floriana Pansini ◽  
Elena Rondi ◽  
...  

Objective: To compare different stereotactic body techniques—intensity-modulated radiotherapy with photons and protons, applied to radiotherapy of prostatic cancer—with simultaneous integrated boost (SIB) on the dominant intraprostatic lesion (DIL). Methods: Ten patients were selected for this planning study. Dosimetric results were compared between volumetric modulated arc therapy, intensity-modulated radiation therapy (IMRT), and intensity-modulated proton therapy both with two (IMPT 2F) and five fields (IMPT 5F) planning while applying the prescription schemes of 7.25 Gy/fraction to the prostate gland and 7.5 Gy/fraction to the DIL in 5 fractions. Results: Comparison of the coverages of the planning target volumes showed that small differences exist. The IMPT-2F-5F techniques allowed higher doses in the targets; conformal indexes resulted similar; homogeneity was better in the photon techniques (2%–5%). Regarding the organs at risk, all the techniques were able to maintain the dose well below the prescribed constraints: in the rectum, the IMPT-2F-5F and IMRT were more efficient in lowering the intermediate doses; in the bladder, the median dose was significantly better in the case of IMPT (2F–5F). In the urethra, the best sparing was achieved only by IMPT-5F. Conclusions: Stereotactic radiotherapy with SIB for localized prostate cancer is feasible with all the investigated techniques. Concerning IMPT, the two-beam technique does not seem to have a greater advantage compared to the standard techniques; the 5-beam technique seems more promising also accounting for the range uncertainty.

2019 ◽  
Vol 19 (1) ◽  
pp. 45-51 ◽  
Author(s):  
Ehab Saad ◽  
Khaled Elshahat ◽  
Hussein Metwally

AbstractBackground:While treating brain metastasis with whole-brain radiotherapy incorporating a simultaneous integrated boost (WBRT-SIB), the risk of hippocampus injury is high. The aim of this study is to compare dosimetrically between intensity-modulated radiotherapy (IMRT) and volumetric-modulated arc therapy (VMAT) in sparing of hippocampus and organs at risk (OARs) and planning target volume (PTV) coverage.Methods:In total, 16 patients presenting with more than one brain metastases were previously treated and then retrospectively planned using VMAT and IMRT techniques. For each patient, a dual-arc VMAT and another IMRT (five beams) plans were created. For both techniques, 30 Gy in 10 fractions was prescribed to the whole brain (WB) minus the hippocampi and 45 Gy in 10 fractions to the tumour with 0·5 cm margin. Dose–volume histogram (DVH), conformity index (CI) and homogeneity index (HI) of PTV, hippocampus mean and maximum dose and other OARs for both techniques were calculated and compared.Results:A statistically significant advantage was found in WB-PTV CI and HI with VMAT, compared to IMRT. There were lower hippocampus mean and maximum doses in VMAT than IMRT. The maximum hippocampus dose ranged between 15·5 and 19·2 Gy and between 18·4 and 20·6 Gy in VMAT and IMRT, respectively. The mean dose of the hippocampus ranged between 11·5 and 17·7 Gy and between 13·2 and 18·3 Gy in VMAT and IMRT, respectively.Conclusion:Using WBRT-SIB technique, VMAT showed better PTV coverage with less mean and maximum doses to the hippocampus than IMRT. Clinical randomised studies are needed to confirm safety and clinical benefit of WBRT-SIB.


2020 ◽  
Vol 38 (6_suppl) ◽  
pp. 299-299
Author(s):  
Anthony Ricco ◽  
Nitai Mukhopadhyay ◽  
Diane Holdford ◽  
Vicki Skinner ◽  
Siddharth Saraiya ◽  
...  

299 Background: This study reports the 5 year toxicity and efficacy data of a phase I/II trial of moderately hypofractionated intensity modulated radiation therapy (IMRT) for localized prostate cancer utilizing a simultaneous integrated boost and pelvic lymph node (LN) coverage. Methods: Men with localized prostate cancer were prospectively enrolled and received IMRT to the prostate +/- seminal vesicles (SVs) +/- LNs based on National Comprehensive Cancer Network (NCCN) guidelines. Low-risk (LR) patients received 69.6 Gy in 29 fractions to the prostate alone; intermediate-risk (IR) and high-risk (HR) patients received 72Gy to the prostate, 54Gy to the SVs, and 50.4Gy to LNs (if risk of LN involvement > 15% by the Roach formula) all in 30 fractions. IR and HR patients received androgen deprivation therapy. Results: Fifty-five patients were enrolled and 49 patients evaluable with a median follow up of 60 months. There were 11 (20%) LR, 23 (41.8%) IR, and 21 (38.2%) HR patients. Twenty-five patients (51%) received prostate and LN treatment. At 5 years, the cumulative incidence of late grade 2+ gastrointestinal (GI) and genitourinary (GU) toxicity was 22.6% and 38.2% respectively. Prevalence rates of late grade 2 GI toxicity at 1, 3, and 5 years was 5.8%, 3.9%, and 5.8% respectively. Late grade 2+ GI toxicities that did not resolve by 60 months included 3 out of 52 patients (5.8%). Prevalence rates of late grade 2 GU toxicity at 1, 3, and 5 years rates were 15.4%, 7.7%, and 13.5% respectively. There were 3 patients (5.8%) who experienced grade 3 GU toxicity and no grade 3 GI toxicities. The biochemical relapse free survival at 5 years for the cohort was 88.3%. There were no local, regional, or distant failures, with all patients still alive at last follow up. Conclusions: Moderate hypofractionation of localized prostate cancer utilizing a simultaneous integrated boost and LN coverage produces excellent biochemical control and acceptable acute/late toxicity. This phase I/II trial adds to maturing data with 5 year outcomes which justify its use for cost and patient convenience factors. Clinical trial information: NCT01117935.


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