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Title: Toward Prostate Cancer Contouring Guidelines on Magnetic Resonance Imaging: Dominant Lesion Gross and Clinical Target Volume Coverage Via Accurate Histology Fusion

Abstract

Purpose: Defining prostate cancer (PCa) lesion clinical target volumes (CTVs) for multiparametric magnetic resonance imaging (mpMRI) could support focal boosting or treatment to improve outcomes or lower morbidity, necessitating appropriate CTV margins for mpMRI-defined gross tumor volumes (GTVs). This study aimed to identify CTV margins yielding 95% coverage of PCa tumors for prospective cases with high likelihood. Methods and Materials: Twenty-five men with biopsy-confirmed clinical stage T1 or T2 PCa underwent pre-prostatectomy mpMRI, yielding T2-weighted, dynamic contrast-enhanced, and apparent diffusion coefficient images. Digitized whole-mount histology was contoured and registered to mpMRI scans (error ≤2 mm). Four observers contoured lesion GTVs on each mpMRI scan. CTVs were defined by isotropic and anisotropic expansion from these GTVs and from multiparametric (unioned) GTVs from 2 to 3 scans. Histologic coverage (proportions of tumor area on co-registered histology inside the CTV, measured for Gleason scores [GSs] ≥6 and ≥7) and prostate sparing (proportions of prostate volume outside the CTV) were measured. Nonparametric histologic-coverage prediction intervals defined minimal margins yielding 95% coverage for prospective cases with 78% to 92% likelihood. Results: On analysis of 72 true-positive tumor detections, 95% coverage margins were 9 to 11 mm (GS ≥ 6) and 8 to 10 mm (GS ≥ 7) for single-sequence GTVs and were 8 mm (GS ≥ 6)more » and 6 mm (GS ≥ 7) for 3-sequence GTVs, yielding CTVs that spared 47% to 81% of prostate tissue for the majority of tumors. Inclusion of T2-weighted contours increased sparing for multiparametric CTVs with 95% coverage margins for GS ≥6, and inclusion of dynamic contrast-enhanced contours increased sparing for GS ≥7. Anisotropic 95% coverage margins increased the sparing proportions to 71% to 86%. Conclusions: Multiparametric magnetic resonance imaging–defined GTVs expanded by appropriate margins may support focal boosting or treatment of PCa; however, these margins, accounting for interobserver and intertumoral variability, may preclude highly conformal CTVs. Multiparametric GTVs and anisotropic margins may reduce the required margins and improve prostate sparing.« less

Authors:
 [1];  [2];  [3];  [4];  [5];  [2]; ;  [6];  [6];  [7];  [6];  [1];  [2]; ;  [8]; ;  [5];  [2];  [1];  [2] more »;  [9]; « less
  1. Robarts Research Institute, University of Western Ontario, London, Ontario (Canada)
  2. (Canada)
  3. (United Kingdom)
  4. (Netherlands)
  5. Lawson Health Research Institute, London, Ontario (Canada)
  6. Department of Medical Imaging, University of Western Ontario, London, Ontario (Canada)
  7. (Australia)
  8. Department of Pathology, University of Western Ontario, London, Ontario (Canada)
  9. Department of Medical Imaging, Sunnybrook Health Sciences Centre, Toronto, Ontario (Canada)
Publication Date:
OSTI Identifier:
22648796
Resource Type:
Journal Article
Resource Relation:
Journal Name: International Journal of Radiation Oncology, Biology and Physics; Journal Volume: 96; Journal Issue: 1; Other Information: Copyright (c) 2016 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
62 RADIOLOGY AND NUCLEAR MEDICINE; ANIMAL TISSUES; ANISOTROPY; DISEASE INCIDENCE; HISTOLOGY; IMAGES; NEOPLASMS; NMR IMAGING; PROSTATE

Citation Formats

Gibson, Eli, Biomedical Engineering, University of Western Ontario, London, Ontario, Centre for Medical Image Computing, University College London, London, Department of Radiology, Radboud University Medical Centre, Nijmegen, Bauman, Glenn S., E-mail: glenn.bauman@lhsc.on.ca, Department of Oncology, University of Western Ontario, London, Ontario, Romagnoli, Cesare, Cool, Derek W., Bastian-Jordan, Matthew, Queensland Health, Brisbane, Queensland, Kassam, Zahra, Gaed, Mena, Department of Pathology, University of Western Ontario, London, Ontario, Moussa, Madeleine, Gómez, José A., Pautler, Stephen E., Chin, Joseph L., Department of Urology, University of Western Ontario, London, Ontario, Crukley, Cathie, Lawson Health Research Institute, London, Ontario, Haider, Masoom A., and and others. Toward Prostate Cancer Contouring Guidelines on Magnetic Resonance Imaging: Dominant Lesion Gross and Clinical Target Volume Coverage Via Accurate Histology Fusion. United States: N. p., 2016. Web. doi:10.1016/J.IJROBP.2016.04.018.
Gibson, Eli, Biomedical Engineering, University of Western Ontario, London, Ontario, Centre for Medical Image Computing, University College London, London, Department of Radiology, Radboud University Medical Centre, Nijmegen, Bauman, Glenn S., E-mail: glenn.bauman@lhsc.on.ca, Department of Oncology, University of Western Ontario, London, Ontario, Romagnoli, Cesare, Cool, Derek W., Bastian-Jordan, Matthew, Queensland Health, Brisbane, Queensland, Kassam, Zahra, Gaed, Mena, Department of Pathology, University of Western Ontario, London, Ontario, Moussa, Madeleine, Gómez, José A., Pautler, Stephen E., Chin, Joseph L., Department of Urology, University of Western Ontario, London, Ontario, Crukley, Cathie, Lawson Health Research Institute, London, Ontario, Haider, Masoom A., & and others. Toward Prostate Cancer Contouring Guidelines on Magnetic Resonance Imaging: Dominant Lesion Gross and Clinical Target Volume Coverage Via Accurate Histology Fusion. United States. doi:10.1016/J.IJROBP.2016.04.018.
Gibson, Eli, Biomedical Engineering, University of Western Ontario, London, Ontario, Centre for Medical Image Computing, University College London, London, Department of Radiology, Radboud University Medical Centre, Nijmegen, Bauman, Glenn S., E-mail: glenn.bauman@lhsc.on.ca, Department of Oncology, University of Western Ontario, London, Ontario, Romagnoli, Cesare, Cool, Derek W., Bastian-Jordan, Matthew, Queensland Health, Brisbane, Queensland, Kassam, Zahra, Gaed, Mena, Department of Pathology, University of Western Ontario, London, Ontario, Moussa, Madeleine, Gómez, José A., Pautler, Stephen E., Chin, Joseph L., Department of Urology, University of Western Ontario, London, Ontario, Crukley, Cathie, Lawson Health Research Institute, London, Ontario, Haider, Masoom A., and and others. 2016. "Toward Prostate Cancer Contouring Guidelines on Magnetic Resonance Imaging: Dominant Lesion Gross and Clinical Target Volume Coverage Via Accurate Histology Fusion". United States. doi:10.1016/J.IJROBP.2016.04.018.
@article{osti_22648796,
title = {Toward Prostate Cancer Contouring Guidelines on Magnetic Resonance Imaging: Dominant Lesion Gross and Clinical Target Volume Coverage Via Accurate Histology Fusion},
author = {Gibson, Eli and Biomedical Engineering, University of Western Ontario, London, Ontario and Centre for Medical Image Computing, University College London, London and Department of Radiology, Radboud University Medical Centre, Nijmegen and Bauman, Glenn S., E-mail: glenn.bauman@lhsc.on.ca and Department of Oncology, University of Western Ontario, London, Ontario and Romagnoli, Cesare and Cool, Derek W. and Bastian-Jordan, Matthew and Queensland Health, Brisbane, Queensland and Kassam, Zahra and Gaed, Mena and Department of Pathology, University of Western Ontario, London, Ontario and Moussa, Madeleine and Gómez, José A. and Pautler, Stephen E. and Chin, Joseph L. and Department of Urology, University of Western Ontario, London, Ontario and Crukley, Cathie and Lawson Health Research Institute, London, Ontario and Haider, Masoom A. and and others},
abstractNote = {Purpose: Defining prostate cancer (PCa) lesion clinical target volumes (CTVs) for multiparametric magnetic resonance imaging (mpMRI) could support focal boosting or treatment to improve outcomes or lower morbidity, necessitating appropriate CTV margins for mpMRI-defined gross tumor volumes (GTVs). This study aimed to identify CTV margins yielding 95% coverage of PCa tumors for prospective cases with high likelihood. Methods and Materials: Twenty-five men with biopsy-confirmed clinical stage T1 or T2 PCa underwent pre-prostatectomy mpMRI, yielding T2-weighted, dynamic contrast-enhanced, and apparent diffusion coefficient images. Digitized whole-mount histology was contoured and registered to mpMRI scans (error ≤2 mm). Four observers contoured lesion GTVs on each mpMRI scan. CTVs were defined by isotropic and anisotropic expansion from these GTVs and from multiparametric (unioned) GTVs from 2 to 3 scans. Histologic coverage (proportions of tumor area on co-registered histology inside the CTV, measured for Gleason scores [GSs] ≥6 and ≥7) and prostate sparing (proportions of prostate volume outside the CTV) were measured. Nonparametric histologic-coverage prediction intervals defined minimal margins yielding 95% coverage for prospective cases with 78% to 92% likelihood. Results: On analysis of 72 true-positive tumor detections, 95% coverage margins were 9 to 11 mm (GS ≥ 6) and 8 to 10 mm (GS ≥ 7) for single-sequence GTVs and were 8 mm (GS ≥ 6) and 6 mm (GS ≥ 7) for 3-sequence GTVs, yielding CTVs that spared 47% to 81% of prostate tissue for the majority of tumors. Inclusion of T2-weighted contours increased sparing for multiparametric CTVs with 95% coverage margins for GS ≥6, and inclusion of dynamic contrast-enhanced contours increased sparing for GS ≥7. Anisotropic 95% coverage margins increased the sparing proportions to 71% to 86%. Conclusions: Multiparametric magnetic resonance imaging–defined GTVs expanded by appropriate margins may support focal boosting or treatment of PCa; however, these margins, accounting for interobserver and intertumoral variability, may preclude highly conformal CTVs. Multiparametric GTVs and anisotropic margins may reduce the required margins and improve prostate sparing.},
doi = {10.1016/J.IJROBP.2016.04.018},
journal = {International Journal of Radiation Oncology, Biology and Physics},
number = 1,
volume = 96,
place = {United States},
year = 2016,
month = 9
}
  • Purpose: To determine whether a relationship exists between the tumor volume (TV) or relative choline content determined using magnetic resonance spectroscopy imaging (MRSI) at 3T and the clinical prognostic parameters for patients with localized prostate cancer (PCa). Methods and Materials: A total of 72 men (mean age, 67.8 {+-} 6.2 years) were stratified as having low-risk (n = 26), intermediate-risk (n = 24), or high-risk (n = 22) PCa. MRSI was performed at 3T using a phased-array coil. Spectra are expressed as the total choline/citrate, total choline plus creatine/citrate, and total choline plus polyamines plus creatine/citrate ratios. The mean ratiomore » of the most pathologic voxels and the MRSI-based TV were also determined. Results: The mean values of the total choline/citrate, total choline plus creatine/citrate, and total choline plus polyamine plus creatine/citrate ratios were greater for Stage T2b or greater tumors vs. Stage T2a or less tumors: 7.53 {+-} 13.60 vs. 2.31 {+-} 5.65 (p = .018), 8.98 {+-} 14.58 vs. 2.56 {+-} 5.70 (p = .016), and 10.32 {+-} 15.47 vs. 3.55 {+-} 6.16 (p = .014), respectively. The mean MRSI-based TV for Stage T2b or greater and Stage T2a or less tumors was significantly different (2.23 {+-} 2.62 cm{sup 3} vs. 1.26 {+-} 2.06 cm{sup 3}, respectively; p = .030). This TV correlated with increased prostate-specific antigen levels (odds ratio, 1.293; p = .012). Patients with high-risk PCa had a larger TV than did the patients with intermediate-risk PCa. A similar result was found for the intermediate-risk group compared with the low-risk group (odds ratio, 1.225; p = .041). Conclusion: Biomarkers expressing the relative choline content and TV were significant parameters for the localization of PCa and could be helpful for determining the prognosis more accurately.« less
  • Purpose: To compare the contours and dose-volume histograms (DVH) of the tumor and organs at risk (OAR) with computed tomography (CT) vs. magnetic resonance imaging (MRI) in cervical cancer brachytherapy. Methods and Materials: Ten patients underwent both MRI and CT after applicator insertion. The dose received by at least 90% of the volume (D{sub 90}), the minimal target dose (D{sub 100}), the volume treated to the prescription dose or greater for tumor for the high-risk (HR) and intermediate-risk (IR) clinical target volume (CTV) and the dose to 0.1 cm{sup 3}, 1 cm{sup 3}, and 2 cm{sup 3} for the OARsmore » were evaluated. A standardized approach to contouring on CT (CT{sub Std}) was developed, implemented (HR- and IR-CTV{sub CTStd}), and compared with the MRI contours. Results: Tumor height, thickness, and total volume measurements, as determined by either CT or CT{sub Std} were not significantly different compared with the MRI volumes. In contrast, the width measurements differed in HR-CTV{sub CTStd} (p = 0.05) and IR-CTV{sub CTStd} (p = 0.01). For the HR-CTV{sub CTStd}, this resulted in statistically significant differences in the volume treated to the prescription dose or greater (MRI, 96% vs. CT{sub Std}, 86%, p = 0.01), D{sub 100} (MRI, 5.4 vs. CT{sub Std}, 3.4, p <0.01), and D{sub 90} (MRI, 8.7 vs. CT{sub Std}, 6.7, p <0.01). Correspondingly, the IR-CTV DVH values on MRI vs. CT{sub Std}, differed in the D{sub 100} (MRI, 3.0 vs. CT{sub Std}, 2.2, p = 0.01) and D{sub 90} (MRI, 5.6 vs. CT{sub Std}, 4.6, p = 0.02). The MRI and CT DVH values of the dose to 0.1 cm{sup 3}, 1 cm{sup 3}, and 2 cm{sup 3} for the OARs were similar. Conclusion: Computed tomography-based or MRI-based scans at brachytherapy are adequate for OAR DVH analysis. However, CT tumor contours can significantly overestimate the tumor width, resulting in significant differences in the D{sub 90}, D{sub 100}, and volume treated to the prescription dose or greater for the HR-CTV compared with that using MRI. MRI remains the standard for CTV definition.« less
  • Purpose: We prospectively compared computed tomography (CT)– and magnetic resonance imaging (MRI)–based high-risk clinical target volume (HR-CTV) contours at the time of brachytherapy for cervical cancer in an effort to identify patients who might benefit most from MRI-based planning. Methods and Materials: Thirty-seven patients who had undergone a pretreatment diagnostic MRI scan were included in the analysis. We delineated the HR-CTV on the brachytherapy CT and brachytherapy MRI scans independently for each patient. We then calculated the absolute volumes for each HR-CTV and the Dice coefficient of similarity (DC, a measure of spatial agreement) for the HR-CTV contours. We identifiedmore » the clinical and tumor factors associated with (1) a discrepancy in volume between the CT HR-CTV and MRI HR-CTV contours; and (2) DC. The mean values were compared using 1-way analysis of variance or paired or unpaired t tests, as appropriate. Simple and multivariable linear regression analyses were used to model the effects of covariates on the outcomes. Results: Patients with International Federation of Gynecology and Obstetrics stage IB to IVA cervical cancer were treated with intracavitary brachytherapy using tandem and ovoid (n=33) or tandem and cylinder (n=4) applicators. The mean CT HR-CTV volume (44.1 cm{sup 3}) was larger than the mean MRI HR-CTV volume (35.1 cm{sup 3}; P<.0001, paired t test). On multivariable analysis, a higher body mass index (BMI) and tumor size ≥5 cm with parametrial invasion on the MRI scan at diagnosis were associated with an increased discrepancy in volume between the HR-CTV contours (P<.02 for both). In addition, the spatial agreement (as measured by DC) between the HR-CTV contours decreased with an increasing BMI (P=.013). Conclusions: We recommend MRI-based brachytherapy planning for patients with tumors >5 cm and parametrial invasion on MRI at diagnosis and for those with a high BMI.« less
  • Purpose: To define a prostate fossa clinical target volume (PF-CTV) for Radiation Therapy Oncology Group (RTOG) trials using postoperative radiotherapy for prostate cancer. Methods and Materials: An RTOG-sponsored meeting was held to define an appropriate PF-CTV after radical prostatectomy. Data were presented describing radiographic failure patterns after surgery. Target volumes used in previous trials were reviewed. Using contours independently submitted by 13 radiation oncologists, a statistical imputation method derived a preliminary 'consensus' PF-CTV. Results: Starting from the model-derived CTV, consensus was reached for a CT image-based PF-CTV. The PF-CTV should extend superiorly from the level of the caudal vas deferensmore » remnant to >8-12 mm inferior to vesicourethral anastomosis (VUA). Below the superior border of the pubic symphysis, the anterior border extends to the posterior aspect of the pubis and posteriorly to the rectum, where it may be concave at the level of the VUA. At this level, the lateral border extends to the levator ani. Above the pubic symphysis, the anterior border should encompass the posterior 1-2 cm of the bladder wall; posteriorly, it is bounded by the mesorectal fascia. At this level, the lateral border is the sacrorectogenitopubic fascia. Seminal vesicle remnants, if present, should be included in the CTV if there is pathologic evidence of their involvement. Conclusions: Consensus on postoperative PF-CTV for RT after prostatectomy was reached and is available as a CT image atlas on the RTOG website. This will allow uniformity in defining PF-CTV for clinical trials that include postprostatectomy RT.« less
  • The purpose of this study was to assess the efficacy of a gross tumor volume (GTV) contouring protocol on interobserver variability between 4 physicians in positron emission therapy/computed tomography (PET/CT) treatment planning of head-and-neck cancer. A GTV contouring protocol for PET/CT treatment planning was developed utilizing 4 stages: Preliminary contouring on CT alone, determination of appropriate PET windowing, accurate image registration, and modification of CT contouring with correctly formatted PET/CT display and rules for modality disagreement. Two neuroradiologists and 2 radiation oncologists (designated as A, B, C, and D, respectively) were given a tutorial of PET/CT coregistered imaging individualized tomore » their skill level, which included a step-by-step explanation of the protocol with clinical examples. Opportunities for questions and hands-on practice were given. The physicians were asked to re-contour 16 head-and-neck patients from Part I on PET/CT fusion imaging. Differences in volume magnitude were analyzed for statistical significance by analysis of variance (ANOVA) and paired t-tests ({alpha} < 0.05). Volume overlap was analyzed for statistical significance using Wilcoxon signed-rank tests ({alpha} < 0.05). Volume overlap increased significantly from Part I to Part II (p < 0.05). One previously significant difference between physicians disappeared with the protocol in place. The mean fusion volume of Physician C, however, remained significantly larger than that of Physician D (p < 0.01). This result is unchanged from Part I. The multidisciplinary contouring protocol significantly improved the coincidence of GTVs contoured by multiple physicians. The magnitudes of the volumes showed marginal improvement in consistency. Developing an institutional contouring protocol for PET/CT treatment planning is highly recommended to reduce interobserver variability.« less