Electronic supplementary material
Preparation of information for participating centres
Items included in the pre-trial CR-ROM
Descriptions of ‘best practice’ for patient immobilisation and acquisition of the planning scan, administration of intravenous (IV) contrast and subsequent handling of contrasted images in the treatment planning system.
Written and pictorial descriptions of the method for planning target volume (PTV) generation from the gross tumour volume (GTV) via the consecutive stages of clinical target volume (CTV), (‘CTVA’ and ‘CTVB’). Margin sizes were adopted from local practice , with multiple CTV stages formalised to correctly account for sub-clinical spread of disease along the line of the oesophagus, radially and below the level of the gastro-oesophageal junction (GOJ). In addition, a method for discretionary posterior modification of CTVB where close to the spinal cord was included.
Dose volume histogram (DVH) requirements (Table 2, column 1) for use with different types of dose calculation algorithms, namely ‘type a’ and ‘type b’ . For ‘type b’, this required an investigative planning study , summarised later.
A plan assessment form (PAF) [see Additional file 3] to maximise correct data return.
Deviation levels for target coverage and OAR doses
Single phase planning
An illustrated planning guide including four problem examples. Use of a single phase plan, which had been shown to deliver lower heart doses than a widely used two phase approach using a ‘lung sparing’ anterior-posterior pair followed by a ‘cord sparing’ three field arrangement [29, 30] was mandated. Since this was not exclusively used in the UK at the time of the trial launch  the planning guide sought to assist with this transition, where required.
An illustrated description of suitable pre-treatment and/or on-treatment verification processes aimed at ensuring accurate reproduction of the planned isocentre position and to manage significant changes to the patient’s external anatomy subsequent to planning.
Pre-trial quality assurance
Benchmark case requirements, analysis and feedback
Structure & Dose Volume Objective
Type a algorithm:
PTV V95% > 99.0%
PTV deviations were not pre-classified but reviewed individually
(98.6, 98.8, 98.9, 98.9%)
Type a algorithm:
PTV point minimum dose >93.0%
Type b algorithm:
PTV V95% > 99.0% - [0.4 x % PTVoverlap]
ICRU maximum dose <107%
120% > max > 107%
2 minor deviations
Heart V40Gy < 30.0%
50% > V40Gy > 30%
V40Gy > 50%
1 minor deviation
Liver V30Gy < 60.0%
70% > V30Gy > 60%
V30Gy > 70%
Combined lung V20Gy < 25.0%
35% > V20Gy > 25%
V20Gy > 35%
18 minor deviations
(6 of which >30%)
Spinal cord PRV D1cc < 40.0Gy
2 major deviations
QA of plan reporting
QA of centre processes
On-trial QA of clinical cases
Feedback and ongoing QA support
Percentage of benchmark cases requiring feedback
Percentage of on-trial cases requiring feedback
Outlining of GTV
Outlining of OARs
Cord PRV margin
Completion of the PAF