The effect of planning algorithms in oesophageal radiotherapy in the context of the SCOPE 1 trial

A rare rarity: Neuroendocrine tumor of the esophagus

Esophageal Neuroendocrine tumors (NETs) are rare, aggressive and lacking specific symptoms. This causes a diagnostic delay, worsening the prognosis. Numerous cases are reported in literature, without a consensus on the management. Our aim was to clarify epidemiology, clinical presentation, diagnostic, therapeutic management of esophageal NETs. Extensive literature search identified a total of 226 articles. One hundred twenty-five articles (n = 1676) met the inclusion criteria, showing that: the incidence of esophageal NET varies geographically; men (60-70 years) are more affected; smoking and alcohol abuse are the major risk factors; dysphagia, weight loss, appetite loss are the most common clinical features. The histotypes include high-grade small and large cell esophageal carcinomas and low-grade carcinoid tumors. Mixed neuroendocrine/non-neuroendocrine neoplasms are the most common. Often the diagnosis occurs randomly on endoscopic examination. Circulating markers, functional combined with conventional imaging contributes to the diagnosis and management. Treatment depends on type, grade and stage of the tumor.

Driving developments in UK oesophageal radiotherapy through the SCOPE trials

BACKGROUND

The SCOPE trials (SCOPE 1, NeoSCOPE and SCOPE 2) have been the backbone of oesophageal RT trials in the UK. Many changes in oesophageal RT techniques have taken place in this time. The SCOPE trials have, in addition to adopting these new techniques, been influential in aiding centres with their implementation. We discuss the progress made through the SCOPE trials and include details of a questionnaire sent to participating centres. to establish the role that trial participation played in RT changes in their centre.

METHODS

Questionnaires were sent to 47 centres, 27 were returned.

RESULTS

100% of centres stated their departmental protocol for TVD was based on the relevant SCOPE trial protocol. 4DCT use has increased from 42 to 71%. Type B planning algorithms, mandated in the NeoSCOPE trial, were used in 79.9% pre NeoSCOPE and now in 83.3%. 12.5% of centres were using a stomach filling protocol pre NeoSCOPE, now risen to 50%. CBCT was mandated for IGRT in the NeoSCOPE trial. 66.7% used this routinely pre NeoSCOPE/SCOPE 2 which has risen to 87.5% in the survey.

CONCLUSION

The results of the questionnaires show how participation in national oesophageal RT trials has led to the adoption of newer RT techniques in UK centres, leading to better patient care.

Quality assurance of the SCOPE 1 trial in oesophageal radiotherapy

BACKGROUND

SCOPE 1 was the first UK based multi-centre trial involving radiotherapy of the oesophagus. A comprehensive radiotherapy trials quality assurance programme was launched with two main aims: 1. To assist centres, where needed, to adapt their radiotherapy techniques in order to achieve protocol compliance and thereby enable their participation in the trial. 2. To support the trial's clinical outcomes by ensuring the consistent planning and delivery of radiotherapy across all participating centres.

METHODS

A detailed information package was provided and centres were required to complete a benchmark case in which the delineated target volumes and organs at risk, dose distribution and completion of a plan assessment form were assessed prior to recruiting patients into the trial. Upon recruiting, the quality assurance (QA) programme continued to monitor the outlining and planning of radiotherapy treatments. Completion of a questionnaire was requested in order to gather information about each centre's equipment and techniques relating to their trial participation and to assess the impact of the trial nationally on standard practice for radiotherapy of the oesophagus. During the trial, advice was available for individual planning issues, and was circulated amongst the SCOPE 1 community in response to common areas of concern using bulletins.

RESULTS

36 centres were supported through QA processes to enable their participation in SCOPE1. We discuss the issues which have arisen throughout this process and present details of the benchmark case solutions, centre questionnaires and on-trial protocol compliance. The range of submitted benchmark case GTV volumes was 29.8-67.8cm3; and PTV volumes 221.9-513.3 cm3. For the dose distributions associated with these volumes, the percentage volume of the lungs receiving 20Gy (V20Gy) ranged from 20.4 to 33.5%. Similarly, heart V40Gy ranged from 16.1 to 33.0%. Incidence of incorrect outlining of OAR volumes increased from 50% of centres at benchmark case, to 64% on trial. Sixty-five percent of centres, who returned the trial questionnaire, stated that their standard practice had changed as a result of their participation in the SCOPE1 trial.

CONCLUSIONS

The SCOPE 1 QA programme outcomes lend support to the trial's clinical conclusions. The range of patient planning outcomes for the benchmark case indicated, at the outset of the trial, the significant degree of variation present in UK oesophageal radiotherapy planning outcomes, despite the presence of a protocol. This supports the case for increasingly detailed definition of practice by means of consensus protocols, training and peer review. The incidence of minor inconsistencies of technique highlights the potential for improved QA systems and the need for sufficient resource for this to be addressed within future trials. As indicated in questionnaire responses, the QA exercise as a whole has contributed to greater consistency of oesophageal radiotherapy in the UK via the adoption into standard practice of elements of the protocol.

TRIAL REGISTRATION

The SCOPE1 trial is an International Standard Randomized Controlled Trial, ISRCTN47718479 .

The influence of dose distribution on treatment outcome in the SCOPE 1 oesophageal cancer trial

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.

Oesophageal Chemoradiotherapy in the UK--current practice and future directions

The SCOPE 1 trial closed to recruitment in early 2012 and has demonstrably improved the quality of UK radiotherapy. It has also shown that there is an enthusiastic upper gastrointestinal clinical oncology community that can successfully complete trials and deliver high-quality radiotherapy. Following on from SCOPE 1, this paper, authored by a consensus of leading UK upper gastrointestinal radiotherapy specialists, attempts to define current best practice and the questions to be answered by future clinical studies. The two main roles for chemoradiotherapy (CRT) in the management of potentially curable oesophageal cancer are definitive (dCRT) and neoadjuvant (naCRT). The rates of local failure after dCRT are consistently high, showing the need to evaluate more effective treatments, both in terms of optimal local and systemic therapeutic components. This will be the primary objective of the next planned UK dCRT trial and here we discuss the role of dose escalation and systemic therapeutic options that will form the basis of that trial. The publication of the Dutch 'CROSS' trial of naCRT has shown that this pre-operative approach can both be given safely and offer a significant survival benefit over surgery alone. This has led to the development of the UK NeoSCOPE trial, due to open in 2013. There will be a translational substudy to this trial and currently available data on the role of biomarkers in predicting response to therapy are discussed. Postoperative reporting of the pathology specimen is discussed, with recommendations for the NeoSCOPE trial. Both of these CRT approaches may benefit from recent developments, such as positron emission tomography/computed tomography and four-dimensional computed tomography for target volume delineation, planning techniques such as intensity-modulated radiotherapy and 'type b' algorithms and new treatment verification methods, such as cone-beam computed tomography. These are discussed here and recommendations made for their use.