Multi-Institutional Phase II Study of Proton Beam Therapy for Organ-Confined Prostate Cancer Focusing on the Incidence of Late Rectal Toxicities

Nihei, Keiji; Ogino, Takashi; Onozawa, Masakatsu; Murayama, Shigeyuki; Fuji, Hiroshi; Murakami, Masao; Hishikawa, Yoshio

doi:10.1016/j.ijrobp.2010.05.027

Cited by 69 publications

(74 citation statements)

References 29 publications

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“…Fields 1 and 2 required 891 spots to cover the PTV volume, while field 3 needed 1701 spots. We assumed a dose prescription of 74 Gy (RBE) in 37 fractions to the isocenter in accordance with a previous report 16 . The Relative Biological Effectiveness (RBE) was set to 1.1.…”

Section: Methodsmentioning

confidence: 99%

“…This value corresponds to the clinical data available on proton therapy. In report 16 , it was shown that biochemical relapse-free survival rate (bNED) at 3 years was 94% for Gleason score < 8 patient group. The similar percentage is also seen in report 18 in which bNED at 5-years was more than 92% for T1-T2a patients with the same dose prescription.…”

Section: Tcp Modelmentioning

confidence: 99%

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Biological effect of dose distortion by fiducial markers in spot‐scanning proton therapy with a limited number of fields: A simulation study

et al. 2012

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Purpose: In accurate proton spot-scanning therapy, continuous target tracking by fluoroscopic X-ray during irradiation is beneficial not only for respiratory moving tumors of lung and liver but also for relatively stationary tumors of prostate. Implanted gold markers have been used with great effect for positioning the target volume by a fluoroscopy, especially for the cases of liver and prostate with the targets surrounded by water-equivalent tissues.However, recent studies have revealed that gold markers can cause a significant underdose in proton therapy. This paper focuses on prostate cancer and explores the possibility that multiple-field irradiation improves the underdose effect by markers on Tumor Control Probability (TCP). Methods:A Monte Carlo simulation was performed to evaluate the dose distortion effect. A spherical gold marker was placed at several characteristic points in a water phantom. Markers were with two different diameters of 2 mm and 1.5 mm, both visible on fluoroscopy. Three beam arrangements of SFUD (single-field uniform dose)were examined: one lateral field, two opposite lateral fields, and three fields (two opposite lateral fields + anterior field). The Relative Biological Effectiveness (RBE) was set to 1.1 and a dose of 74 Gy (RBE) was delivered to the target of a typical prostate size in 37 fractions. The ratios of TCP to that without the marker (TCP r ) were compared with the parameters of the marker sizes, number of fields, and marker positions. To take into account the dependence of biological parameters in TCP model,  values of 1.5, 3, and 10 Gy (RBE) were considered.Results: It was found that the marker of 1.5 mm diameter does not affect the TCPs with all  values when two or more fields are used. On the other hand, if the marker size is 2 mm, more than two irradiation fields are required to suppress the decrease in TCP from TCP r by less than 3%. This is especially true when multiple (two or three) markers are used for alignment of a patient. Conclusions:It is recommended that 1.5 mm markers be used to avoid the reduction of TCP as well as to spare the surrounding critical organs, as long as the markers are visible on X-ray fluoroscopy. When 2 mm markers are implanted, more than two fields should be used and the markers should not be placed close to the distal edge of any of the beams.

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Section: Methodsmentioning

confidence: 99%

Section: Tcp Modelmentioning

confidence: 99%

Biological effect of dose distortion by fiducial markers in spot‐scanning proton therapy with a limited number of fields: A simulation study

et al. 2012

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“…Clinical findings indicate that in cases of early tolerance, developing complications at G2 and G3 grades is respectively 5-12% and 1-2% likely for the urinary tract but is respectively less than 3.5% and 0.5% for the rectum [95,96,99]. With the passing of time after treatment, complication rates rise after 5 years at the G2 level; 21-31% in the urinary tract and 10-18% in the rectum [88,95,96,[102][103][104][105][106][107].…”

Section: Prostate Cancer (Pc)mentioning

confidence: 96%

“…Dosimetry studies have shown a 30-50% dose reduction to critical organs when using proton beam compared with the photon beam, even when advanced radiotherapy techniques are applied [94][95][96][97][98][99][100]. Reducing the mean dose of the rectum or its wall, the bladder and small intestine, (and regrettably increasing the dose to femoral bone heads) is observed in cases where the proton beam is used as booster in IMRT [101].…”

Section: Prostate Cancer (Pc)mentioning

confidence: 99%

“…With the passing of time after treatment, complication rates rise after 5 years at the G2 level; 21-31% in the urinary tract and 10-18% in the rectum [88,95,96,[102][103][104][105][106][107]. It should be emphasised that late complications are more common for those patients where attempts at dose escalation were made using proton radiotherapy alone or in the booster form after conventional radiation therapy [103,107,109].…”

Section: Prostate Cancer (Pc)mentioning

confidence: 99%

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Proton radiotherapy for treating the most common carcinomas

Sas-Korczyńska

Jakubowicz²,

Reinfuss³

2017

Nowotwory. Journal of Oncology

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A literature review is presented on proton radiotherapy when used for treating the most common carcinoma types such as cancer of the lung, breast and prostate. This is based on analytic parameters of dosimetry and clinical outcomes (efficacy and toxicity), along with studies on cost-effectiveness as compared to those achieved by conventional photon radiotherapy. NOWOTWORY J Oncol 2016; 66, 5: 396-402

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