The influence of radiotherapy treatment method on dose distribution and its relation to patient outcome in the SCOPE 1 oesophageal cancer trial using Type B algorithms

Carrington, R., Spezi, Emiliano ORCID: https://orcid.org/0000-0002-1452-8813, Gwynne, S., Dutton, P., Hurt, Chris Nicholas ORCID: https://orcid.org/0000-0003-1206-8355, Staffurth, John Nicholas ORCID: https://orcid.org/0000-0002-7834-3172 and Crosby, T. 2016. The influence of radiotherapy treatment method on dose distribution and its relation to patient outcome in the SCOPE 1 oesophageal cancer trial using Type B algorithms. Radiation Oncology (London, England) 11 , 19. 10.1186/s13014-016-0594-x

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Abstract

Purpose The first aim of this study was to assess plan quality using a conformity index (CI) and analyse its influence on patient outcome. The second aim was to identify whether clinical and technological factors including planning treatment volume (PTV) volume and treatment delivery method could be related to the CI value. Methods and materials By extending the original concept of the mean distance to conformity (MDC) index, the OverMDC and UnderMDC of the 95 % isodose line (50Gy prescribed dose) to the PTV was calculated for 97 patients from the UK SCOPE 1 trial (ISCRT47718479). Data preparation was carried out in CERR, with Kaplan-Meier and multivariate analysis undertaken in EUCLID and further tests in Microsoft Excel and IBM’s SPSS. Results A statistically significant breakpoint in the overall survival data, independent of cetuximab, was found with OverMDC (4.4 mm, p < 0.05). This was not the case with UnderMDC. There was a statistically significant difference in PTV volume either side of the OverMDC breakpoint (Mann Whitney p < 0.001) and in OverMDC value dependent on the treatment delivery method (mean IMRT = 2.1 mm, mean 3D-CRT = 4.1 mm Mann Whitney p < 0.001). Re-planning the worst performing patients according to OverMDC from 3D-CRT to VMAT resulted in a mean reduction in OverMDC of 2.8 mm (1.6–4.0 mm). OverMDC was not significant in multivariate analysis that included age, sex, staging, tumour type, and position. Conclusion Although not significant when included in multivariate analysis, we have shown in univariate analysis that a patient’s OverMDC is correlated with overall survival. OverMDC is strongly related to IMRT and to a lesser extent with PTV volume. We recommend that VMAT planning should be used for oesophageal planning when available and that attention should be paid to the conformity of the 95 % to the PTV.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Engineering Medicine
Subjects:	R Medicine > RC Internal medicine > RC0254 Neoplasms. Tumors. Oncology (including Cancer)
Publisher:	BioMed Central
ISSN:	1748-717X
Date of First Compliant Deposit:	3 May 2016
Date of Acceptance:	27 January 2016
Last Modified:	18 Jan 2024 09:00
URI:	https://orca.cardiff.ac.uk/id/eprint/90206

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