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Comparison and consensus guidelines for delineation of clinical target volume for CT- and MR-based brachytherapy in locally advanced cervical cancer. Int J Radiat Oncol Biol Phys 2014 Oct 01;90(2):320-8 PMID: 25304792 PMCID: PMC4194192

Pubmed ID

25304792

DOI

10.1016/j.ijrobp.2014.06.005

Abstract

OBJECTIVE: To create and compare consensus clinical target volume (CTV) contours for computed tomography (CT) and 3-Tesla (3-T) magnetic resonance (MR) image-based cervical-cancer brachytherapy.

METHODS AND MATERIALS: Twenty-three experts in gynecologic radiation oncology contoured the same 3 cervical cancer brachytherapy cases: 1 stage IIB near-complete response (CR) case with a tandem and ovoid, 1 stage IIB partial response (PR) case with tandem and ovoid with needles, and 1 stage IB2 CR case with a tandem and ring applicator. The CT contours were completed before the MRI contours. These were analyzed for consistency and clarity of target delineation using an expectation maximization algorithm for simultaneous truth and performance level estimation (STAPLE), with κ statistics as a measure of agreement between participants. The conformity index was calculated for each of the 6 data sets. Dice coefficients were generated to compare the CT and MR contours of the same case.

RESULTS: For all 3 cases, the mean tumor volume was smaller on MR than on CT (P<.001). The κ and conformity index estimates were slightly higher for CT, indicating a higher level of agreement on CT. The Dice coefficients were 89% for the stage IB2 case with a CR, 74% for the stage IIB case with a PR, and 57% for the stage IIB case with a CR.

CONCLUSION: In a comparison of MR-contoured with CT-contoured CTV volumes, the higher level of agreement on CT may be due to the more distinct contrast medium visible on the images at the time of brachytherapy. MR at the time of brachytherapy may be of greatest benefit in patients with large tumors with parametrial extension that have a partial or complete response to external beam. On the basis of these results, a 95% consensus volume was generated for CT and for MR. Online contouring atlases are available for instruction at http://www.nrgoncology.org/Resources/ContouringAtlases/GYNCervicalBrachytherapy.aspx.

Author List

Viswanathan AN, Erickson B, Gaffney DK, Beriwal S, Bhatia SK, Lee Burnett O 3rd, D'Souza DP, Patil N, Haddock MG, Jhingran A, Jones EL, Kunos CA, Lee LJ, Lin LL, Mayr NA, Petersen I, Petric P, Portelance L, Small W Jr, Strauss JB, Townamchai K, Wolfson AH, Yashar CM, Bosch W

Author

Beth A. Erickson MD Professor in the Radiation Oncology department at Medical College of Wisconsin




Scopus

2-s2.0-84908206463   59 Citations

MESH terms used to index this publication - Major topics in bold

Adenocarcinoma
Brachytherapy
Consensus
Female
Humans
Magnetic Resonance Imaging
Neoplasm, Residual
Tomography, X-Ray Computed
Tumor Burden
Uterine Cervical Neoplasms
jenkins-FCD Prod-353 9ccd8489072cb19f5b9f808bb23ed672c582f41e