High accumulated doses to the inferior rectum are associated with late gastro-intestinal toxicity in a case-control study of prostate cancer patients treated with radiotherapy

Casares-Magaz, Oscar; Bülow, Steffen; Pettersson, Niclas; Moiseenko, Vitali; Pedersen, Jesper; Thor, Maria; Einck, John; Hopper, Austin; Knopp, Rick; Muren, L.P.

doi:10.1080/0284186x.2019.1632476

Cited by 14 publications

(17 citation statements)

References 32 publications

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“…When comparing planned and delivered dose, total accumulated daily dose to the RW was systematically lower than planned dose (p < 0.001). This effect has been reported previously [14,16] and is thought to be due to interfraction motion causing a blurring of the highest dose regions. However, when focusing on SRRs, accumulated dose was greater than planned dose (p < 0.001), an effect masked when considering the full RW.…”

Section: Discussionsupporting

confidence: 71%

“…A novelty of the work presented here is not only the comparison of SRR and full RW dose-toxicity analysis for planned dose, but also for total accumulated dose. The rectum is highly susceptible to motion and deformation [31], and therefore planned dose is not equal to delivered dose [8,9,14,16,41]. When comparing planned and delivered dose, total accumulated daily dose to the RW was systematically lower than planned dose (p < 0.001).…”

Section: Discussionmentioning

confidence: 99%

“…In lieu of widely available systems for accumulating daily delivered dose to the rectum, previous studies have addressed this problem using approaches such as estimating motion-inclusive dose through statistical simulation [42] or by extrapolation of dose calculated using a sample of cone-beam CT (CBCT) scans acquired throughout the course of treatment [14,41]. Casares-Magaz et al conducted a case-control study of 24 patients whereby accumulated dose was estimated through rigid registration of dose from 13 CBCT scans per patient.…”

Section: Discussionmentioning

confidence: 99%

“…However, it is widely acknowledged that DVH parameters are limited by their lack of spatial dose information [5][6][7]. Studies into more appropriate dose https://doi.org/10.1016/j.phro.2020.05.006 descriptors for the rectal wall (RW) have generally been focused on parameterisation of dose surface maps (DSMs) where the RW is virtually cut and unfolded to a normalised 2D map so that geometric dose information can be preserved [5,[7][8][9][10][11][12][13][14][15][16].…”

Section: Introductionmentioning

confidence: 99%

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Associations between voxel-level accumulated dose and rectal toxicity in prostate radiotherapy

Shelley

Sutcliffe

Thomas

et al. 2020

Physics and Imaging in Radiation Oncology

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Background and Purpose: Associations between dose and rectal toxicity in prostate radiotherapy are generally poorly understood. Evaluating spatial dose distributions to the rectal wall (RW) may lead to improvements in dose-toxicity modelling by incorporating geometric information, masked by dose-volume histograms. Furthermore, predictive power may be strengthened by incorporating the effects of interfraction motion into delivered dose calculations.Here we interrogate 3D dose distributions for patients with and without toxicity to identify rectal subregions at risk (SRR), and compare the discriminatory ability of planned and delivered dose. Material and Methods: Daily delivered dose to the rectum was calculated using image guidance scans, and accumulated at the voxel level using biomechanical finite element modelling. SRRs were statistically determined for rectal bleeding, proctitis, faecal incontinence and stool frequency from a training set (n = 139), and tested on a validation set (n = 47). Results: SRR patterns differed per endpoint. Analysing dose to SRRs improved discriminative ability with respect to the full RW for three of four endpoints. Training set AUC and OR analysis produced stronger toxicity associations from accumulated dose than planned dose. For rectal bleeding in particular, accumulated dose to the SRR (AUC 0.76) improved upon dose-toxicity associations derived from planned dose to the RW (AUC 0.63). However, validation results could not be considered significant. Conclusions: Voxel-level analysis of dose to the RW revealed SRRs associated with rectal toxicity, suggesting nonhomogeneous intra-organ radiosensitivity. Incorporating spatial features of accumulated delivered dose improved dose-toxicity associations. This may be an important tool for adaptive radiotherapy in the future.

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Section: Discussionsupporting

confidence: 71%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Associations between voxel-level accumulated dose and rectal toxicity in prostate radiotherapy

Shelley

Sutcliffe

Thomas

et al. 2020

Physics and Imaging in Radiation Oncology

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“…Several papers addressed normal tissue morbidity, and not least the relationship between objective clinical observations and patient reported outcome measures (PROMs) [67][68][69][70][71]. The patient's involvement in evaluating the side effects of the treatment is a must, but at the same time the balance between PROM and clinical objective detected side effects should be kept, as we are otherwise unable to modify the treatment in a favorable way for the patients.…”

mentioning

confidence: 99%

BIGART 2019 – adapting to the future

et al. 2019

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The use of dose surface maps as a tool to investigate spatial dose delivery accuracy for the rectum during prostate radiotherapy

Patrick,

Kildea

2024

J Applied Clin Med Phys

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PurposeThis study aims to address the lack of spatial dose comparisons of planned and delivered rectal doses during prostate radiotherapy by using dose‐surface maps (DSMs) to analyze dose delivery accuracy and comparing these results to those derived using DVHs.MethodsTwo independent cohorts were used in this study: twenty patients treated with 36.25 Gy in five fractions (SBRT) and 20 treated with 60 Gy in 20 fractions (IMRT). Daily delivered rectum doses for each patient were retrospectively calculated using daily CBCT images. For each cohort, planned and average‐delivered DVHs were generated and compared, as were planned and accumulated DSMs. Permutation testing was used to identify DVH metrics and DSM regions where significant dose differences occurred. Changes in rectal volume and position between planning and delivery were also evaluated to determine possible correlation to dosimetric changes.ResultsFor both cohorts, DVHs and DSMs reported conflicting findings on how planned and delivered rectum doses differed from each other. DVH analysis determined average‐delivered DVHs were on average 7.1% ± 7.6% (p ≤ 0.002) and 5.0 ± 7.4% (p ≤ 0.021) higher than planned for the IMRT and SBRT cohorts, respectively. Meanwhile, DSM analysis found average delivered posterior rectal wall dose was 3.8 ± 0.6 Gy (p = 0.014) lower than planned in the IMRT cohort and no significant dose differences in the SBRT cohort. Observed dose differences were moderately correlated with anterior‐posterior rectal wall motion, as well as PTV superior‐inferior motion in the IMRT cohort. Evidence of both these relationships were discernable in DSMs.ConclusionDSMs enabled spatial investigations of planned and delivered doses can uncover associations with interfraction motion that are otherwise masked in DVHs. Investigations of dose delivery accuracy in radiotherapy may benefit from using DSMs over DVHs for certain organs such as the rectum.

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High accumulated doses to the inferior rectum are associated with late gastro-intestinal toxicity in a case-control study of prostate cancer patients treated with radiotherapy

Cited by 14 publications

References 32 publications

Associations between voxel-level accumulated dose and rectal toxicity in prostate radiotherapy

Associations between voxel-level accumulated dose and rectal toxicity in prostate radiotherapy

BIGART 2019 – adapting to the future

The use of dose surface maps as a tool to investigate spatial dose delivery accuracy for the rectum during prostate radiotherapy

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