Relationship and Applicability of Biologic Rectal Dose and Rectal Bleeding for Standard, Moderate, and Extreme Fractionation Proton Therapy

2020 ◽  
Vol 108 (3) ◽  
pp. e886
Author(s):  
C.E. Vargas ◽  
R.S. Bhangoo ◽  
M. Petersen ◽  
C.S. Thorpe ◽  
W.W. Wong ◽  
...  
Keyword(s):  
Proton Therapy ◽  
Rectal Bleeding ◽  
Rectal Dose

scholarly journals Biologically Effective Dose and Rectal Bleeding in Definitive Proton Therapy for Prostate Cancer

2021 ◽  
Author(s):  
Ronik S. Bhangoo ◽  
Molly M. Petersen ◽  
Gabriella F. Bulman ◽  
Carlos E. Vargas ◽  
Cameron S. Thorpe ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Proton Therapy ◽  
Rectal Bleeding ◽  
Univariate Analysis ◽  
Youden Index ◽  
Bleeding Events ◽  
Conventional Fractionation ◽  
Rectal Dose ◽  
Multivariate Logistic Model ◽  
Clinically Significant

Abstract Purpose and Objectives With increasing use of hypofractionation and extreme hypofractionation for prostate cancer, rectal dose-volume histogram (DVH) parameters that apply across dose fractionations may be helpful for treatment planning in clinical practice. We present an exploratory analysis of biologically effective rectal dose (BED) and equivalent rectal dose in 2 Gy fractions (EQD2) for rectal bleeding in patients treated with proton therapy across dose fractionations. Materials and Methods From 2016 to 2018, 243 patients with prostate cancer were treated with definitive proton therapy. Rectal DVH parameters were obtained from treatment plans, and rectal bleeding events were recorded. The BED and EQD2 transformations were applied to each rectal DVH parameter. Univariate analysis using logistic regression was used to determine DVH parameters that were significant predictors of grade ≥ 2 rectal bleeding. Youden index was used to determine optimum cutoffs for clinically meaningful DVH constraints. Stepwise model-selection criteria were then applied to fit a “best” multivariate logistic model for predicting Common Terminology Criteria for Adverse Events grade ≥ 2 rectal bleeding. Results Conventional fractionation, hypofractionation, and extreme hypofractionation were prescribed to 117 (48%), 84 (34%), and 42 (17.3%) patients, respectively. With a median follow-up of 20 (2.5-40) months, 10 (4.1%) patients experienced rectal bleeding. On univariate analysis, multiple rectal DVH parameters were significantly associated with rectal bleeding across BED, EQD2, and nominal doses. The BED volume receiving 55 Gy > 13.91% was found to be statistically and clinically significant. The BED volume receiving 55 Gy remained statistically significant for an association with rectal bleeding in the multivariate model (odds ratio, 9.81; 95% confidence interval, 2.4-40.5; P = .002). Conclusion In patients undergoing definitive proton therapy for prostate cancer, dose to the rectum and volume of the rectum receiving the dose were significantly associated with rectal bleeding across conventional fractionation, hypofractionation, and extreme hypofractionation when using BED and EQD2 transformations.

scholarly journals Preliminary analysis of prostate positional displacement using hydrogel spacer during the course of proton therapy for prostate cancer

2020 ◽  
Author(s):  
Hiroki Sato ◽  
Takahiro Kato ◽  
Tomoaki Motoyanagi ◽  
Kimihiro Takemasa ◽  
Yuki Narita ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Proton Therapy ◽  
Rectal Dose ◽  
Prostate Motion ◽  
Significant Difference ◽  
Risk Prostate Cancer ◽  
Bony Anatomy ◽  
Study Population ◽  
Planning Ct ◽  
Anterior Posterior

Abstract In recent years, a novel technique has been employed to maintain a distance between the prostate and the rectum by transperineally injecting a hydrogel spacer (HS). However, the effect of HS on the prostate positional displacement is poorly understood, despite its stability with HS in place. In this study, we investigated the effect of HS insertion on the interfraction prostate motion during the course of proton therapy (PT) for Japanese prostate cancer patients. The study population consisted of 22 cases of intermediate-risk prostate cancer with 11 cases with HS insertion and 11 cases without HS insertion. The irradiation position and preparation were similar for both groups. To test for reproducibility, regular confirmation computed tomography (RCCT) was done four times during the treatment period, and five times overall [including treatment planning CT (TPCT)] in each patient. Considering the prostate position of the TPCT as the reference, the change in the center of gravity of the prostate relative to the bony anatomy in the RCCTs of each patient was determined in the left–right (LR), superior–inferior (SI) and anterior–posterior (AP) directions. As a result, no significant difference was observed across the groups in the LR and SI directions. Conversely, a significant difference was observed in the AP direction (P < 0.05). The proportion of the 3D vector length ≤5 mm was 95% in the inserted group, but 55% in the non-inserted group. Therefore, HS is not only effective in reducing rectal dose, but may also contribute to the positional reproducibility of the prostate.

scholarly journals Comparison of rectal dose reduction by a hydrogel spacer among 3D conformal radiotherapy, volumetric-modulated arc therapy, helical tomotherapy, CyberKnife and proton therapy

2020 ◽  
Vol 61 (3) ◽  
pp. 487-493 ◽  
Author(s):  
Masahide Saito ◽  
Toshihiro Suzuki ◽  
Yuya Sugama ◽  
Kan Marino ◽  
Naoki Sano ◽  
...  
Keyword(s):  
Dose Reduction ◽  
Proton Therapy ◽  
Helical Tomotherapy ◽  
Volumetric Modulated Arc Therapy ◽  
Conformal Radiotherapy ◽  
Ct Images ◽  
High Dose ◽  
3D Conformal Radiotherapy ◽  
Rectal Dose ◽  
Arc Therapy

Abstract This study aimed to evaluate the rectal dose reduction with hydrogel spacer in 3D conformal radiotherapy (3DCRT), volumetric modulated arc therapy (VMAT), helical tomotherapy (HT), CyberKnife (CK) and proton therapy. Twenty patients who had hydrogel spacer for prostate radiotherapy were retrospectively enrolled. Computed tomography (CT) images with or without hydrogel spacer were used to evaluate rectal dose reduction. In total, 200 plans (20 patients × 2 CT images × 5 techniques) were created using the following criteria: 3DCRT, VMAT and HT [76 Gy/38 fractions (Fr), planning target volume (PTV) D50%], CK (36.25 Gy/5 Fr, PTV D95%) and proton therapy (63 GyE/21 Fr, PTV D50%). Rectal dose reduction was evaluated using low-/middle-dose (D20%, D50% and D80%) and high-dose (D2%) ranges. Rectal dose reduction of each dose index was compared for each technique. Significant rectal dose reduction (P < 0.001) between the treatment plans on pre- and post-CT images were achieved for all modalities for D50%, D20% and D2%. In particular, the dose reduction of high-dose (D2%) ranges were −40.61 ± 11.19, −32.44 ± 5.51, −25.90 ± 9.89, −13.63 ± 8.27 and −8.06 ± 4.19%, for proton therapy, CK, HT, VMAT and 3DCRT, respectively. The area under the rectum dose–volume histogram curves were 34.15 ± 3.67 and 34.36 ± 5.24% (P = 0.7841) for 3DCRT with hydrogel spacer and VMAT without hydrogel spacer, respectively. Our results indicated that 3DCRT with hydrogel spacer would reduce the medical cost by replacing the conventional VMAT without spacer for prostate cancer treatment, from the point of view of the rectal dose. For the high-dose gradient region, proton therapy and SBRT with CK showed larger rectal dose reduction than other techniques.

Proton therapy for prostate cancer: An analysis of rectal toxicity outcomes at University of Florida Proton Therapy Institute (UFPTI).

2014 ◽  
Vol 32 (4_suppl) ◽  
pp. 161-161
Author(s):  
Rovel J. Colaco ◽  
Bradford S. Hoppe ◽  
Randal H. Henderson ◽  
Romaine Charles Nichols ◽  
Christopher G. Morris ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Radiation Dose ◽  
Proton Therapy ◽  
Rectal Bleeding ◽  
Treatment Technique ◽  
Rectal Toxicity ◽  
University Of Florida ◽  
Increased Risk ◽  
Potential Risk Factors ◽  
Grade 3

161 Background: We aimed to characterize gastrointestinal effects of proton therapy (PT) in patients treated for prostate cancer, identify factors associated with rectal bleeding (RB), and compare RB between patients on investigational protocols (IP) versus outcome tracking protocols (OTP). Methods: 1,290 patients treated consecutively with PT between August 2006 and June 2010 were studied. Pre-existing potential risk factors for RB (hemorrhoids, diabetes, aspirin, other anticoagulants) were recorded. Common terminology criteria for adverse events (CTCAE version 4.0) were used to grade toxicity. Median follow up was 3.5 years. Results: The majority (94.6%) of Grade 2 or higher gastrointestinal toxicity (GR2+) events after PT were rectal bleeding. GR1 RB occurred in 390 (30.2%) of patients, including those requiring no prescription intervention (82.6%) and those placed on a vitamin A regimen (16.3%). GR2 RB occurred in 14.7% of patients, including patients requiring prescription rectal suppositories (9.5%), cautery (4.9%), or hyperbaric oxygen (0.3%). Grade 3 (GR3) occurred in 0.8% of patients, including those requiring transfusion (0.6%) or colostomy (0.1%). Multivariate analyses showed that pretreatment daily aspirin (p=0.03), other anticoagulation (p=0.001), and the volume of rectum exposed to radiation dose levels (V70) (<.0001) were associated with an increased risk of Gr2+RB. Patients treated on investigational protocols (IP) had similar toxicity rates as those treated on an outcomes tracking protocol (OTP). Reduced rectal toxicity was noted in latter years of the study, which correlated with changes in treatment technique, pretreatment evaluation, and post-treatment supportive care regimens. Conclusions: PT was associated with low rates of GI toxicity, the most common toxicity being transient RB. GR2+RB is strongly associated with patient use of aspirin, other anti-coagulation and radiation dose volume parameters.

887 Impact of mean rectal dose on late rectal bleeding following conformal radiotherapy for prostate cancer: dose volume effect

2003 ◽  
Vol 1 (5) ◽  
pp. S267
Author(s):  
A. Zapatero ◽  
F. Garcia-Vicente ◽  
I. Modolell ◽  
P. Alcantara ◽  
A. Floriano ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Rectal Bleeding ◽  
Conformal Radiotherapy ◽  
Volume Effect ◽  
Rectal Dose ◽  
Dose Volume

Impact of mean rectal dose on late rectal bleeding after conformal radiotherapy for prostate cancer: Dose–volume effect

2004 ◽  
Vol 59 (5) ◽  
pp. 1343-1351 ◽  
Author(s):  
Almudena Zapatero ◽  
Feliciano García-Vicente ◽  
Ignasi Modolell ◽  
Pino Alcántara ◽  
Alejandro Floriano ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Rectal Bleeding ◽  
Conformal Radiotherapy ◽  
Volume Effect ◽  
Rectal Dose ◽  
Dose Volume
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