Analysis of prostate bed motion using an endorectal balloon and cone beam computed tomography during postprostatectomy radiotherapy

Joo, Ji Hyeon; Kim, Yeon Joo; Kim, Young Seok; Cho, Young Pil; Lee, Ho Yeon; Jeong, Chul; Kwak, Jungwon; Cho, Byoung Chul

doi:10.2147/ott.s98112

Cited by 5 publications

(7 citation statements)

References 22 publications

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“…Because of the large pelvic lymphatic area covered by CTV, mild hypofractionated IMRT of 2.2 Gy per day was adopted in the current study. The incidence of toxicity seems to be similar or lower than in those other studies, which can be attributed to the use of ERB in 93.5% patients and meticulous IGRT [ 8 ]. The only patient with severe rectal bleeding after SRT in the present study underwent SRT without the use of ERB in 2008, as it was not introduced yet.…”

Section: Discussionsupporting

confidence: 55%

“…Patients were instructed to have empty bladders and rectums before CT simulation and subsequent treatment. ERB has been used since 2009 to avoid damage to the anterior rectal wall and to decrease the irradiated rectal volume according to previously reported methods [ 8 , 11 ]. CTV included the prostate beds, external iliac, internal iliac, and obturator lymph nodal areas.…”

Section: Methodsmentioning

confidence: 99%

“…With the advent of intensity-modulated radiotherapy (IMRT) and image-guided radiotherapy (IGRT), several studies have reported advantages of these methods in terms of dosimetric parameters of organs at risk, translating to a clinically significant reduction in toxicity [ 6 , 7 ]. Endorectal balloon (ERB) is often used to protect the rectal wall and to achieve better reproducibility, thereby facilitating smaller margins [ 8 , 9 ].…”

Section: Introductionmentioning

confidence: 99%

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Image-guided, whole-pelvic, intensity-modulated radiotherapy for biochemical recurrence following radical prostatectomy in high-risk prostate cancer patients

et al. 2018

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BackgroundThe optimal field size of salvage radiotherapy (SRT) for biochemical recurrence, particularly for patients with high-risk prostate cancer, remains undefined. This retrospective analysis was performed to investigate oncological outcomes as well as treatment-related toxicity following salvage intensity-modulated radiotherapy (IMRT) to the whole pelvis and to compare the results with other studies implementing a small field size of the prostate bed.MethodsThe medical records of 170 patients with high-risk prostate cancer who received SRT for biochemical recurrence following prostatectomy were reviewed. Whole-pelvic IMRT was administered with a median dose of 66 Gy in 30 fractions. To improve treatment accuracy, an endorectal balloon device and daily cone-beam computed tomography were utilized. Androgen-deprivation therapy combined with SRT was administered to 97 (57.1%) patients.ResultsEventually, 68 (40.0%) patients showed biochemical progression (BCP) after SRT. With a median follow-up period of 56 months, the 5-year BCP-free survival was 38.6%. The overall and cause-specific survival rates were 90.9% and 96.7%, respectively. Regarding BCP-free survival analysis, pathological T stage, persistent prostate-specific antigen (PSA) elevation after prostatectomy, and preSRT PSA level were significant prognostic factors on univariate analysis. On multivariate analysis, pathological T stage and preSRT PSA value retained their significance. Acute and late grade-3 genitourinary toxicities were observed in one (0.6%) and five (2.9%) patients, respectively. One patient each developed acute and late grade-3 gastrointestinal toxicity.ConclusionSRT to whole pelvis using IMRT and image guidance is as safe as SRT to the prostate bed, but its efficacy should be confirmed in ongoing randomized trials. PreSRT PSA was the only controllable prognostic factor, suggesting the benefit of early SRT.

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Section: Discussionsupporting

confidence: 55%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Image-guided, whole-pelvic, intensity-modulated radiotherapy for biochemical recurrence following radical prostatectomy in high-risk prostate cancer patients

et al. 2018

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“…An endorectal balloon was used to improve the position of the rectum, and after insertion and inflation with 60 cc of air, the balloon was fixed in place with an individual adjustable stopper. Details on the planning CT acquisitions have been described elsewhere 17,18 . All of the patients underwent 15 megavolt (MV) 7-field IMRT.…”

Section: Methodsmentioning

confidence: 99%

Fluence-map generation for prostate intensity-modulated radiotherapy planning using a deep-neural-network

Lee

Kim

Kwak

et al. 2019

Sci Rep

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A deep-neural-network (DNN) was successfully used to predict clinically-acceptable dose distributions from organ contours for intensity-modulated radiotherapy (IMRT). To provide the next step in the DNN-based plan automation, we propose a DNN that directly generates beam fluence maps from the organ contours and volumetric dose distributions, without inverse planning. We collected 240 prostate IMRT plans and used to train a DNN using organ contours and dose distributions. After training was done, we made 45 synthetic plans (SPs) using the generated fluence-maps and compared them with clinical plans (CP) using various plan quality metrics including homogeneity and conformity indices for the target and dose constraints for organs at risk, including rectum, bladder, and bowel. The network was able to generate fluence maps with small errors. The qualities of the SPs were comparable to the corresponding CPs. The homogeneity index of the target was slightly worse in the SPs, but there was no difference in conformity index of the target, V60Gy of rectum, the V60Gy of bladder and the V45Gy of bowel. The time taken for generating fluence maps and qualities of SPs demonstrated the proposed method will improve efficiency of the treatment planning and help maintain the quality of plans.

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“…With the advent of hypofractionation and SBRT in the post-prostatectomy setting, more stringent dosimetric constraints may be required for organs at risk (OARs) [6][7][8]. Thus, an endorectal balloon (ERB) may need to be considered to immobilize the target and to spare normal organs by pushing away the large bowel and inflating the rectal volume [9,10]. While an ERB may lead to more consistent rectal filling and target immobilization, it can lead to patient discomfort and an increased anterior rectal wall dose [10,11].…”

Section: Introductionmentioning

confidence: 99%

Clinical Practice Evolvement for Post-Operative Prostate Cancer Radiotherapy—Part 1: Consistent Organs at Risk Management with Advanced Image Guidance

Laughlin

Vargas

et al. 2022

Cancers

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Purpose: Post-operative prostate cancer patients are treated with full bladder instruction and the use of an endorectal balloon (ERB). We reassessed the efficacy of this practice based on daily image guidance and dose delivery using high-quality iterative reconstructed cone-beam CT (iCBCT). Methods: Fractional dose delivery was calculated on daily iCBCT for 314 fractions from 14 post-operative prostate patients (8 with and 6 without ERB) treated with volumetric modulated radiotherapy (VMAT). All patients were positioned using novel iCBCT during image guidance. The bladder, rectal wall, femoral heads, and prostate bed clinical tumor volume (CTV) were contoured and verified on daily iCBCT. The dose-volume parameters of the contoured organs at risk (OAR) and CTV coverage were assessed for the clinical impact of daily bladder volume variations and the use of ERB. Minimum bladder volume was studied, and a straightforward bladder instruction was explored for easy clinical adoption. Results: A “minimum bladder” contour, the overlap between the original bladder contour and a 15 mm anterior and superior expansion from prostate bed PTV, was confirmed to be effective in identifying cases that might fail a bladder constraint of V65% <60%. The average difference between the maximum and minimum bladder volumes for each patient was 277.1 mL. The daily bladder volumes varied from 62.4 to 590.7 mL and ranged from 29 to 286% of the corresponding planning bladder volume. The bladder constraint of V65% <60% was met in almost all fractions (98%). CTVs (D90%, D95%, and D98%) remained well-covered regardless of the absolute bladder volume daily variation or the presence of the endorectal balloon. Patients with an endorectal balloon showed smaller variation but a higher average maximum rectal wall dose (D0.03mL: 104.3% of the prescription) compared to patients without (103.3%). Conclusions: A “minimum bladder” contour was determined that can be easily generated and followed to ensure sufficient bladder sparing. Further analysis and validation are needed to confirm the utility of the minimal bladder contour. Accurate dose delivery can be achieved for prostate bed target coverage and OAR sparing with or without the use of ERB.

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Analysis of prostate bed motion using an endorectal balloon and cone beam computed tomography during postprostatectomy radiotherapy

Cited by 5 publications

References 22 publications

Image-guided, whole-pelvic, intensity-modulated radiotherapy for biochemical recurrence following radical prostatectomy in high-risk prostate cancer patients

Image-guided, whole-pelvic, intensity-modulated radiotherapy for biochemical recurrence following radical prostatectomy in high-risk prostate cancer patients

Fluence-map generation for prostate intensity-modulated radiotherapy planning using a deep-neural-network

Clinical Practice Evolvement for Post-Operative Prostate Cancer Radiotherapy—Part 1: Consistent Organs at Risk Management with Advanced Image Guidance

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