Reducing interobserver variation of boost-CTV delineation in breast conserving radiation therapy using a pre-operative CT and delineation guidelines

Boersma, Liesbeth J.; Janssen, Tomas; Elkhuizen, Paula H.M.; Poortmans, Philip; van der Sangen, Maurice; Scholten, Astrid N.; Hanbeukers, Bianca; Duppen, Joop C.; Hurkmans, Coen; van Vliet, Corine

doi:10.1016/J.RADONC.2011.12.021

Title

Reducing interobserver variation of boost-CTV delineation in breast conserving radiation therapy using a pre-operative CT and delineation guidelines

Author

Boersma, Liesbeth J.

Janssen, Tomas

Elkhuizen, Paula H.M.

Poortmans, Philip

van der Sangen, Maurice

Scholten, Astrid N.

Hanbeukers, Bianca

Duppen, Joop C.

Hurkmans, Coen

van Vliet, Corine

Abstract

Aims: To investigate whether using a pre-operative CT scan (Preop-CT) (1) decreases interobserver variation of boost-CTV delineation in breast conserving therapy (BCT), and (2) influences the size of the delineated volumes. Patients and methods: Thirty cT1-2N0-1 breast cancer patients underwent a CT-scan in radiation treatment position, prior to and after lumpectomy. Five observers delineated a boost-CTV, both with and without access to the Preop-CT. For each patient and for each observer pair, the conformity index (Cl) and the distance between the centres of mass (COMd) for both boost volumes were calculated. In addition, all delineated volumes including the standard deviation (SD) with respect to the median delineation were calculated. Results: Using a Preop-CT reduced the mean COMd of the boost-CTV from 1.1 cm to 1.0 cm (p < 0.001). No effect was seen on the Cl. but the boost-CTV volume reduced from 42 cc to 36 cc (p = 0.005), implying a reduction of interobserver variation. We saw no significant change in the SD. Conclusion: Use of a Preop-CT in BCT results in a modest but statistically significant reduction in interobserver variation of the boost-CTV delineations and in a significant reduction in the boost-CTV volume. (C) 2012 Elsevier Ireland Ltd. All rights reserved. Radiotherapy and Oncology 103 (2012) 178-182

Language

English

Source (journal)

Radiotherapy and oncology. - Amsterdam

Source (book)

30th Anniversary Meeting of the, European-Society-for-Radiotherapy-and-Oncology (ESTRO) / 11th Biennial, ESTRO International Oncology Forum (EIOF), MAY 08-12, 2011, London, ENGLAND

Publication

Clare : Elsevier ireland ltd , 2012

ISSN

0167-8140

DOI

10.1016/J.RADONC.2011.12.021

Volume/pages

103 :2 (2012) , p. 178-182

ISI

000304220900008

Pubmed ID

22265730