Hypofractionation in Prostate Cancer Using Proton Beam

Quinn, Thomas J.; Hamstra, Daniel A.

doi:10.1016/j.ijrobp.2019.08.006

Cited by 3 publications

(4 citation statements)

References 18 publications

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“…Moreover, highly conformal dose distribution of PBT might contribute to the further reduction of acute patient-reported toxicity profile of hypofractionated RT. 31 Indeed, Vapiwala et al reported significant reduction of acute grade 3 urinary toxicity of patients who received PBT compared with those who received IMRT (2.7% in IMRT vs. 0% in PBT (P = 0.002)), 32 and the rate of acute grade 3 urinary toxicity was 0% in the current study. Regarding GI toxicity, all the patients in our cohort did not receive a hydrogel spacer between prostate and rectum.…”

Section: Discussionsupporting

confidence: 46%

“…Although further research on this issue is required to fill the gap between theoretical expectations and the clinical outcomes observed in our study, our data suggest that hypofractionated PBT using fraction sizes of 2.5 Gy (RBE) and 3.0 Gy (RBE) is as safe as conventional PBT (2.0 Gy (RBE)) in terms of early toxicity. Moreover, highly conformal dose distribution of PBT might contribute to the further reduction of acute and patient‐reported toxicity profile of hypofractionated RT 31 . Indeed, Vapiwala et al reported significant reduction of acute grade 3 urinary toxicity of patients who received PBT compared with those who received IMRT (2.7% in IMRT vs. 0% in PBT ( P = 0.002)), 32 and the rate of acute grade 3 urinary toxicity was 0% in the current study.…”

Section: Discussionsupporting

confidence: 45%

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Acute toxicity and patient‐reported symptom score after conventional versus moderately hypofractionated proton therapy for prostate cancer

Iizumi

Ishikawa

Sekino

et al. 2021

J of Medical Radiation Sci

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Introduction To confirm the feasibility of hypofractionated proton beam therapy (PBT), we compared the acute adverse event rates and International Prostate Symptom Score (IPSS) in prostate cancer patients treated with hypofractionated versus conventionally fractionated (2.0 Gy relative biological effectiveness (RBE)/fraction) PBT. Methods We reviewed 289 patients with prostate cancer, of whom 73, 100, and 116 patients were treated with 2.0, 2.5, and 3.0 Gy (RBE)/fraction, respectively. The endpoints were acute genitourinary and gastrointestinal toxicities and the IPSS, evaluated up to 6 months after PBT initiation. Results No significant differences were found in acute toxicity rates or the IPSS among the fractionation schedules. Diabetes mellitus, age, and androgen deprivation therapy were not identified as factors associated with the IPSS. Conclusion There were no significant differences in adverse events or quality of life among the three fractionation schedules early after PBT.

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Section: Discussionsupporting

confidence: 46%

Section: Discussionsupporting

confidence: 45%

Acute toxicity and patient‐reported symptom score after conventional versus moderately hypofractionated proton therapy for prostate cancer

Iizumi

Ishikawa

Sekino

et al. 2021

J of Medical Radiation Sci

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“…Last but not least, compared to collimation the focused minibeams offer the highest possible dose rates at the target. In particular the latter topic is an ongoing trend in the radiation oncology community for three reasons: the mitigation of moving targets [70][71][72][73], the exploration of hypofractionation [74][75][76] and the potential of reduced normal tissue toxicity due to the FLASH-effect at ultra-high dose rate [32,77]. The topic of dose rate i.e.…”

Section: Minibeam Irradiation Methods -Collimation Versus Focusingmentioning

confidence: 99%

Preclinical Challenges in Proton Minibeam Radiotherapy: Physics and Biomedical Aspects

et al. 2020

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The concept of spatial fractionation in radiotherapy was developed for better sparing of normal tissue in the entrance channel of radiation. Spatial fractionation utilizing proton minibeam radiotherapy (pMBRT) promises to be advantageous compared to X-ray minibeams due to higher dose conformity at the tumor. Preclinical in vivo experiments conducted with pMBRT in mouse ear models or in rat brains support the prospects, but the research about the radiobiological mechanisms and the search for adequate application parameters delivering the most beneficial minibeam therapy is still in its infancy. Concerning preclinical research, we consider glioma, non-small cell lung cancer and hepatocellular carcinoma as the most promising targets and propose investigating the effects on healthy tissue, especially neuronal cells and abdominal organs. The experimental setups for preclinical pMBRT used so far follow different technological approaches, and experience technical limitations when addressing the current questions in the field. We review the crucial physics parameters necessary for proton minibeam production and link them to the technological challenges to be solved for providing an optimal research environment. We consider focusing of pencil or planar minibeams in a scanning approach superior compared to collimation due to less beam halos, higher peak-to-valley dose ratios and higher achievable dose rates. A possible solution to serve such a focusing system with a high-quality proton beam at all relevant energies is identified to be a 3 GHz radio-frequency linear accelerator. We propose using a 16 MeV proton beam from an existing tandem accelerator injected into a linear post-accelerator, boosted up to 70 MeV, and finally delivered to an imaging and positioning end-station suitable for small animal irradiation. Ion-optical simulations show that this combination can generate focused proton minibeams with sizes down to 0.1 mm at 18 nA mean proton current - sufficient for all relevant preclinical experiments. This technology is expected to offer powerful and versatile tools for unleashing structured and advanced preclinical pMBRT studies at the limits and also has the potential to enable a next step into precision tumor therapy.

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“…In recent years, hypofractionated RT for PC has become the standard of care when the target is limited to the prostate and seminal vesicles (SVs). Several reports have shown that moderate or ultrahypofractionated RT (high dose per day) provides good biochemical control that is comparable to conventional fractionated RT [7][8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Optimal Bladder Volume for Hypofractionated Proton Therapy in Each Localized Prostate Cancer Risk Group

Narita,

Kato,

Ishikawa

et al. 2023

Cureus

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BackgroundThis study aimed to determine the optimal bladder volume (BV) for hypofractionated proton therapy in prostate cancer (PC). Materials and methodsTwo hundred patients with PC were enrolled in this study and classified into low-, intermediate-, and highrisk groups. Treatment planning was performed by assuming a hypofractionated schedule of 63 Gy (relative biological effectiveness) in 21 fractions. The dose indices of the bladder (V 60 and V 50 ) were calculated and classified into four groups according to the BV. A cutoff value with a 95% confidence interval was calculated on the basis of the mean and standard deviation of the dose indices. These values were compared with the dose constraints (V 60 < 15 % and V 50 < 30 %). ResultsThe dose indices were higher in the high-risk group than in the other risk groups. The cutoff value exceeded dose constraints in the low-and intermediate-risk groups with a BV of ≦ 149 cc. Additionally, the cutoff value exceeded the dose constraint in the high-risk group with a BV of ≦ 199 cc. In all the cases, the group with a BV of ≧ 200 cc was below the dose constraint. ConclusionsIn this study, the relationship between the dose and volume of the bladder in hypofractionated PT for PC was evaluated using a 95% CI to determine the optimal BV. The BV should be changed for each risk group, and a larger BV is required for a high-risk group than for other risk groups.

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Hypofractionation in Prostate Cancer Using Proton Beam

Cited by 3 publications

References 18 publications

Acute toxicity and patient‐reported symptom score after conventional versus moderately hypofractionated proton therapy for prostate cancer

Acute toxicity and patient‐reported symptom score after conventional versus moderately hypofractionated proton therapy for prostate cancer

Preclinical Challenges in Proton Minibeam Radiotherapy: Physics and Biomedical Aspects

Optimal Bladder Volume for Hypofractionated Proton Therapy in Each Localized Prostate Cancer Risk Group

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