PMID- 34454046
OWN - NLM
STAT- MEDLINE
DCOM- 20220307
LR  - 20220307
IS  - 1879-355X (Electronic)
IS  - 0360-3016 (Linking)
VI  - 112
IP  - 1
DP  - 2022 Jan 1
TI  - Thecal Sac Contouring as a Surrogate for the Cauda Equina and Intracanal Spinal 
      Nerve Roots for Spine Stereotactic Body Radiation Therapy (SBRT): Contour 
      Variability and Recommendations for Safe Practice.
PG  - 114-120
LID - S0360-3016(21)02711-5 [pii]
LID - 10.1016/j.ijrobp.2021.08.023 [doi]
AB  - PURPOSE: To present interobserver variability in thecal sac (TS) delineation 
      based on contours generated by 8 radiation oncologists experienced in spine 
      stereotactic body radiation therapy and to propose contouring recommendations to 
      standardize practice. METHODS AND MATERIALS: In the setting of a larger 
      contouring study that reported target volume delineation guidelines specific to 
      sacral metastases, 8 academically based radiation oncologists with dedicated 
      spine stereotactic body radiation therapy programs independently contoured the TS 
      as a surrogate for the cauda equina and intracanal spinal nerve roots. Uniform 
      treatment planning simulation computed tomography datasets fused with T1, T2, and 
      T1 post gadolinium magnetic resonance imaging for each case were distributed to 
      each radiation oncologist. All contours were analyzed and agreement was 
      calculated using both Dice similarity coefficient and simultaneous truth and 
      performance level estimation with kappa statistics. RESULTS: A fair level of 
      simultaneous truth and performance level estimation agreement was observed 
      between practitioners, with a mean kappa agreement of 0.38 (range, 0.210.55) and 
      the mean Dice similarity coefficient (+/- standard deviation, with range) was 0.43 
      (0.36 +/- 0.1 to -0.53 +/-0.1). Recommendations for a reference TS contour, 
      accounting for the variations in practice observed in this study, include 
      contouring the TS to encompass all the intrathecal spinal nerve roots, and caudal 
      to the termination of the TS, the bony canal can be contoured as a surrogate for 
      the extra thecal nerves roots that run within it. CONCLUSIONS: This study shows 
      that even among high-volume practitioners, there is a lack of uniformity when 
      contouring the TS. Further modifications may be required once dosimetric data on 
      nerve tolerance to ablative doses, and pattern of failure analyses of clinical 
      data sets using these recommendations, become available. The contouring 
      recommendations were designed as a guide to enable consistent and safe contouring 
      across general practice.
CI  - Copyright (c) 2021 Elsevier Inc. All rights reserved.
FAU - Dunne, Emma M
AU  - Dunne EM
AD  - Department of Radiation Oncology, BC Cancer-Vancouver Centre, Vancouver, British 
      Columbia, Canada. Electronic address: emmamaria.dunne@gmail.com.
FAU - Lo, Simon S
AU  - Lo SS
AD  - Department of Radiation Oncology, University of Washington, Seattle, Washington.
FAU - Liu, Mitchell C
AU  - Liu MC
AD  - Department of Radiation Oncology, BC Cancer-Vancouver Centre, Vancouver, British 
      Columbia, Canada.
FAU - Bergman, Alanah
AU  - Bergman A
AD  - Department of Radiation Oncology, BC Cancer-Vancouver Centre, Vancouver, British 
      Columbia, Canada.
FAU - Kosztyla, Robert
AU  - Kosztyla R
AD  - Department of Radiation Oncology, BC Cancer-Vancouver Centre, Vancouver, British 
      Columbia, Canada.
FAU - Chang, Eric L
AU  - Chang EL
AD  - University of Southern California Keck School of Medicine, Los Angeles, 
      California.
FAU - Chang, Ung-Kyu
AU  - Chang UK
AD  - Department of Neurosurgery, Korea Institute of Radiological & Medical Sciences, 
      Seoul, Republic of (South) Korea.
FAU - Chao, Samuel T
AU  - Chao ST
AD  - Department of Radiation Oncology, Taussig Cancer Center, Cleveland Clinic, 
      Cleveland, Ohio.
FAU - Dea, Nicolas
AU  - Dea N
AD  - Vancouver Spine Surgery Institute, Division of Neurosurgery, Department of 
      Surgery, University of British Columbia, Vancouver General Hospital, Vancouver, 
      British Columbia, Canada.
FAU - Faruqi, Salman
AU  - Faruqi S
AD  - Department of Radiation Oncology, Tom Baker Cancer Centre, University of Calgary, 
      Calgary, Alberta, Canada.
FAU - Ghia, Amol J
AU  - Ghia AJ
AD  - Department of Radiation Oncology, The University of Texas MD Anderson Cancer 
      Center, Houston, Texas.
FAU - Redmond, Kristin J
AU  - Redmond KJ
AD  - Johns Hopkins University School of Medicine, Baltimore, Maryland.
FAU - Soltys, Scott G
AU  - Soltys SG
AD  - Department of Radiation Oncology, Stanford Cancer Institute, Stanford, 
      California.
FAU - Sahgal, Arjun
AU  - Sahgal A
AD  - Department of Radiation Oncology, Odette Cancer Centre, Sunnybrook Health 
      Sciences Centre, University of Toronto, Toronto, Ontario, Canada.
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20210825
PL  - United States
TA  - Int J Radiat Oncol Biol Phys
JT  - International journal of radiation oncology, biology, physics
JID - 7603616
SB  - IM
MH  - *Cauda Equina/diagnostic imaging
MH  - Humans
MH  - Magnetic Resonance Imaging/methods
MH  - *Radiosurgery
MH  - Radiotherapy Planning, Computer-Assisted/methods
MH  - Sacrum
MH  - Spinal Nerve Roots/diagnostic imaging
EDAT- 2021/08/29 06:00
MHDA- 2022/03/08 06:00
CRDT- 2021/08/28 20:11
PHST- 2021/04/23 00:00 [received]
PHST- 2021/08/12 00:00 [revised]
PHST- 2021/08/15 00:00 [accepted]
PHST- 2021/08/29 06:00 [pubmed]
PHST- 2022/03/08 06:00 [medline]
PHST- 2021/08/28 20:11 [entrez]
AID - S0360-3016(21)02711-5 [pii]
AID - 10.1016/j.ijrobp.2021.08.023 [doi]
PST - ppublish
SO  - Int J Radiat Oncol Biol Phys. 2022 Jan 1;112(1):114-120. doi: 
      10.1016/j.ijrobp.2021.08.023. Epub 2021 Aug 25.