Proton beam therapy: perspectives on the National Health Service England clinical service and research programme

OPTIma: simplifying calorimetry for proton computed tomography in high proton flux environments

Objective.Proton computed tomography (pCT) offers a potential route to reducing range uncertainties for proton therapy treatment planning, however the current trend towards high current spot scanning treatment systems leads to high proton fluxes which are challenging for existing systems. Here we demonstrate a novel approach to energy reconstruction, referred to as 'de-averaging', which allows individual proton energies to be recovered using only a measurement of their integrated energy without the need for spatial information from the calorimeter.Approach.The method is evaluated in the context of the Optimising Proton Therapy through Imaging (OPTIma) system which uses a simple, relatively inexpensive, scintillator-based calorimeter that reports only the integrated energy deposited by all protons within a cyclotron period, alongside a silicon strip based tracking system capable of reconstructing individual protons in a high flux environment. GEANT4 simulations have been performed to examine the performance of such a system at a modern commercial cyclotron facility using aσ≈ 10 mm beam for currents in the range 10-50 pA at the nozzle.Main results.Apart from low-density lung tissue, a discrepancy of less than 1% on the Relative Stopping Power is found for all other considered tissues when embedded within a 150 mm spherical Perspex phantom in the 10-30 pA current range, and for some tissues even up to 50 pA.Significance.By removing the need for the calorimeter system to provide spatial information, it is hoped that the de-averaging approach can facilitate clinically relevant, cost effective and less complex calorimeter systems for performing high current pCTs.

Choosing the right questions - A systematic review of patient reported outcome measures used in radiotherapy and proton beam therapy

The implementation of PROMs into clinical practice has been shown to improve quality of care. This systematic review aims to identify which PROMs are suitable for implementation within routine clinical practice in a radiotherapy or PBT service.The bibliographic databases MEDLINE, EMBASE and EMCARE were searched. Articles published between 1st January 2008 to 1st June 2023, that reported PROMs being utilised as an outcome measure were included. Inclusion criteria also included being written in English, involving human patients, aged 16 and above, receiving external beam radiotherapy or PBT for six defined tumour sites. PROMs identified within the included articles were subjected to quality assessment using the COSMIN reporting guidelines. Results are reported as per PRISMA guidelines. A total of 268 studies were identified in the search, of which 52 fulfilled the inclusion criteria. The use of 39 different PROMs was reported. The PROMs identified were mostly tumour or site-specific quality of life (n = 23) measures but also included generic cancer (n = 3), health-related quality-of-life (n = 6), and symptom specific (n = 7) measures.None of the PROMs identified received a high GRADE score for good content. There were 13 PROMs that received a moderate GRADE score. The remaining PROMs either had limited evidence of development and validation within the patient cohorts investigated, or lacked relevance or comprehensiveness needed for routine PROMs collection in a radiotherapy or PBT service.This review highlights that there are a wide variety of PROMs being utilised within radiotherapy research, but most lack specificity to radiotherapy side-effects. There is a risk that by using non-specific PROMs in clinical practice, patients might not receive the supportive care that they need.

Hitting the Target: Developing High-quality Evidence for Proton Beam Therapy Through Randomised Controlled Trials

The National Health Service strategy for the delivery of proton beam therapy (PBT) in the UK provides a unique opportunity to deliver high-quality evidence for PBT through randomised controlled trials (RCTs). We present a summary of three UK PBT RCTs in progress, including consideration of their key design characteristics and outcome assessments, to inform and support future PBT trial development. The first three UK multicentre phase III PBT RCTs (TORPEdO, PARABLE and APPROACH), will compare PBT with photon radiotherapy for oropharyngeal squamous cell carcinoma, breast cancer and oligodendroglioma, respectively. All three studies were designed by multidisciplinary teams, which combined expertise from clinicians, clinical trialists and scientists with strong patient advocacy and guidance from national radiotherapy research networks and international collaborators. Consistent across all three studies is a focus on the reduction of long-term radiotherapy-related toxicities and an evaluation of patient-reported outcomes and health-related quality of life, which will address key uncertainties regarding the clinical benefits of PBT. Innovative translational components will provide insights into mechanisms of toxicity and help to frame the key future research questions regarding PBT. The UK radiotherapy research community is developing and delivering an internationally impactful PBT research portfolio. The combination of data from RCTs with prospectively collected data from a national PBT outcomes registry will provide an innovative, high-quality repository for PBT research and the platform to design and deliver future trials of PBT.

Tumour response to hypoxia: understanding the hypoxic tumour microenvironment to improve treatment outcome in solid tumours

Hypoxia is a common feature of solid tumours affecting their biology and response to therapy. One of the main transcription factors activated by hypoxia is hypoxia-inducible factor (HIF), which regulates the expression of genes involved in various aspects of tumourigenesis including proliferative capacity, angiogenesis, immune evasion, metabolic reprogramming, extracellular matrix (ECM) remodelling, and cell migration. This can negatively impact patient outcomes by inducing therapeutic resistance. The importance of hypoxia is clearly demonstrated by continued research into finding clinically relevant hypoxia biomarkers, and hypoxia-targeting therapies. One of the problems is the lack of clinically applicable methods of hypoxia detection, and lack of standardisation. Additionally, a lot of the methods of detecting hypoxia do not take into consideration the complexity of the hypoxic tumour microenvironment (TME). Therefore, this needs further elucidation as approximately 50% of solid tumours are hypoxic. The ECM is important component of the hypoxic TME, and is developed by both cancer associated fibroblasts (CAFs) and tumour cells. However, it is important to distinguish the different roles to develop both biomarkers and novel compounds. Fibronectin (FN), collagen (COL) and hyaluronic acid (HA) are important components of the ECM that create ECM fibres. These fibres are crosslinked by specific enzymes including lysyl oxidase (LOX) which regulates the stiffness of tumours and induces fibrosis. This is partially regulated by HIFs. The review highlights the importance of understanding the role of matrix stiffness in different solid tumours as current data shows contradictory results on the impact on therapeutic resistance. The review also indicates that further research is needed into identifying different CAF subtypes and their exact roles; with some showing pro-tumorigenic capacity and others having anti-tumorigenic roles. This has made it difficult to fully elucidate the role of CAFs within the TME. However, it is clear that this is an important area of research that requires unravelling as current strategies to target CAFs have resulted in worsened prognosis. The role of immune cells within the tumour microenvironment is also discussed as hypoxia has been associated with modulating immune cells to create an anti-tumorigenic environment. Which has led to the development of immunotherapies including PD-L1. These hypoxia-induced changes can confer resistance to conventional therapies, such as chemotherapy, radiotherapy, and immunotherapy. This review summarizes the current knowledge on the impact of hypoxia on the TME and its implications for therapy resistance. It also discusses the potential of hypoxia biomarkers as prognostic and predictive indictors of treatment response, as well as the challenges and opportunities of targeting hypoxia in clinical trials.

Clinical Trials Radiographers identifying priority challenges associated with implementing a national programme of clinical trials in the United Kingdom's first proton beam therapy centre

Objectives

This article is an evaluation of the current trial processes within a national proton beam therapy (PBT) clinical trial service in the United Kingdom. The work within the article identifies priority challenges associated with the implementation of PBT trials with a view to improving patient trial processes.

Methods

The nominal group technique (NGT) was used. Five Clinical Trials Radiographers were asked the target question "what are the major challenges when implementing PBT clinical trials and facilitating PBT trial-related activities?" Participants individually and silently listed their challenges to the target question. Following this, group discussion clarified and refined responses. Participants then individually selected five challenges that they deemed most pertinent to the target question, giving a weighted score (out of 10). Individual scores were combined to provide a ranked, weighted order of challenges. Further group discussion identified improvement strategies to the highest scored challenges.

Results

After combining lists generated by participants, 59 challenges were identified. Group discussion eliminated 27 responses. Eighteen were merged, resulting in 14 challenges. The two challenges that ranked highest were: (i) lack of initial understanding of the responsibilities of teams and who the relevant stakeholders were, and (ii) that a national PBT service requires the provision of shared care across multi-disciplinary teams and sites. Improvement areas include the development of shared protocols, clarifying stakeholder responsibilities and improving communication between centres to streamline PBT trial processes.

Conclusions

This work has identified priority areas requiring development to improve the conduct of a national PBT clinical trials programme.

Advances in knowledge

This is the first publication to evaluate current clinical trial processes for the United Kingdom's PBT service.

Proton beam therapy in paediatric cancer: Anticipating the opening of the Australian Bragg Centre for Proton Therapy and Research

Proton Beam Therapy (PBT) has the potential to improve paediatric cancer care by reducing radiation exposure and thus long-term toxicities. Ethical concerns and debates surrounding the treatment, such as eligibility and accessibility, are ongoing in Australia. The Australian Bragg Centre for Proton Therapy and Research (ABCPTR) (named after Sir William Henry Bragg who described the Bragg peak in his laboratory at the University of Adelaide in 1903) aims to increase access to PBT in Australasia and offer a patient-centred care approach. Research is underway to assess PBT's safety and cost-effectiveness, using tools including Normal Tissue Complication Probability (NTCP) models. Collaborative efforts are focused on developing tailored survivorship clinics to enhance patient follow-up and quality of life. With the anticipated opening of the ABCPTR, Australia is preparing to take a significant step in radiation oncology, offering new research opportunities and creating a publicly funded treatment centre. The initiative aims to balance treatment efficacy with patient care, setting the stage for a future in which radiation therapy will reduce long-term side effects compared to the current standard of care. The implementation of PBT in Australia represents a complex and promising approach to paediatric oncology. This article provides an overview of the current landscape, highlighting the potential benefits and challenges of a treatment that could redefine the quality of survivorship and contribute to global research and best clinical practice.

The use of radiotherapy, surgery and chemotherapy in the curative treatment of cancer: results from the FORTY (Favourable Outcomes from RadioTherapY) project

OBJECTIVES

Radiotherapy, surgery and chemotherapy play key roles in the curative treatment of cancer, alone and in combination. Quantifying their roles is essential for equipment provision and workforce planning. The estimate that 40% of cancer patients are cured by RT has been used extensively to inform and influence policy but is relatively old and warrants review.

METHODS

Patient, tumour and treatment event data was obtained for the 5 year period from 2009 to 2013, allowing a further 5 years for survival outcomes to be known. We analysed patient-level data on utilisation of surgery, radiotherapy, and chemotherapy in cancer patients in England. Data were sourced from Public Health England, using National Cancer Registrations, the National Radiotherapy Dataset (RTDS) and the Systemic Anti-Cancer Therapy Dataset (SACT). All tumour sites (excluding C44) and ages were included. We analysed three cohorts: all patients [n = 1,029,569], patients who survived 5 years or more [n = 537,970] and patients who survived <5 years [n = 491,599].

RESULTS

Overall cancer-specific 5-year survival was 52%, and in those patients, surgery was the most common curative treatment, with 80% receiving surgery, alone or in combination; radiotherapy was delivered to 39% and chemotherapy to 29%; 45% received two and 13% all three modalities.

CONCLUSIONS

The high proportion receiving multi-modality treatment emphasises the importance of integrated, resourced, multidisciplinary cancer care. Radiotherapy was delivered to almost 40% of patients who survived 5 years which underlines its importance in cancer management.

ADVANCES IN KNOWLEDGE

The results are essential in planning cancer services. They also inform the public health narrative.

Assessing Equity of Access to Proton Beam Therapy: A Literature Review

Proton beam therapy (PBT) is one of the most advanced radiotherapy technologies, with growing evidence to support its use in specific clinical scenarios and exponential growth of demand and capacity worldwide over the past few decades. However, geographical inequalities persist in the distribution of PBT centres, which translate into variations in access and use of this technology. The aim of this work was to look at the factors that contribute to these inequalities, to help raise awareness among stakeholders, governments and policy makers. A literature search was conducted using the Population, Intervention, Comparison, Outcomes (PICO) criteria. The same search strategy was run in Embase and Medline and identified 242 records, which were screened for manual review. Of these, 24 were deemed relevant and were included in this analysis. Most of the 24 publications included in this review originated from the USA (22/24) and involved paediatric patients, teenagers and young adults (61% for children and/or teenagers and young adults versus 39% for adults). The most reported indicator of disparity was socioeconomic status (16/24), followed by geographical location (13/24). All the studies evaluated in this review showed disparities in the access to PBT. As paediatric patients make up a significant proportion of the PBT-eligible patients, equity of access to PBT also raises ethical considerations. Therefore, further research is needed into the equity of access to PBT to reduce the care gap.

Proton beam radiotherapy for choroidal and ciliary body melanoma in the UK-national audit of referral patterns of 1084 cases

INTRODUCTION

Proton beam therapy has been utilised for the treatment of uveal melanoma in the UK for over 30 years, undertaken under a single centre. In the UK, all ocular tumours are treated at one of four centres. We aimed to understand the variation in referral patterns to the UK proton service, capturing all uveal melanoma patients treated with this modality.

METHODS

Retrospective analysis of data regarding all patients treated at the Clatterbridge Proton service between January 2004 and December 2014.

RESULTS

A total of 1084 patients with uveal melanoma were treated. The mean age was 57 years (range 9-90 years), basal diameter of 11.5 mm (range 2.0-23.4 mm) and tumour thickness of 3.9 mm (range 0.1-15.4 mm). The majority were TNM stage I (39%) or II (36%). The distance to the optic nerve varied from 0 to 24.5 mm with 148 (14%) of patients having ciliary body involvement. There were variations in the phenotypic characteristic of the tumours treated with protons from different centres, with London referring predominantly small tumours at the posterior pole, Glasgow referring large tumours often at the ciliary body and Liverpool sending a mix of these groups.

DISCUSSION

In the UK, common indications for the use of proton treatment in uveal melanoma include small tumours in the posterior pole poorly accessible for plaque treatment (adjacent to the disc), tumours at the posterior pole affecting the fovea and large anterior tumours traditionally too large for brachytherapy. This is the first UK-wide audit enabling the capture of all patients treated at the single proton centre.

Outcomes of Patients Treated in the UK Proton Overseas Programme: Non-central Nervous System Group

AIMS

The UK Proton Overseas Programme (POP) was launched in 2008. The Proton Clinical Outcomes Unit (PCOU) warehouses a centralised registry for collection, curation and analysis of all outcomes data for all National Health Service-funded UK patients referred and treated abroad with proton beam therapy (PBT) via the POP. Outcomes are reported and analysed here for patients diagnosed with non-central nervous system tumours treated from 2008 to September 2020 via the POP.

MATERIALS AND METHODS

All non-central nervous system tumour files for treatments as of 30 September 2020 were interrogated for follow-up information, and type (following CTCAE v4) and time of onset of any late (>90 days post-PBT completion) grade 3-5 toxicities.

RESULTS

Four hundred and ninety-five patients were analysed. The median follow-up was 2.1 years (0-9.3 years). The median age was 11 years (0-69 years). 70.3% of patients were paediatric (<16 years). Rhabdomyosarcoma (RMS) and Ewing sarcoma were the most common diagnoses (42.6% and 34.1%). 51.3% of treated patients were for head and neck (H&N) tumours. At last known follow-up, 86.1% of all patients were alive, with a 2-year survival rate of 88.3% and 2-year local control of 90.3%. Mortality and local control were worse for adults (≥25 years) than for the younger groups. The grade 3 toxicity rate was 12.6%, with a median onset of 2.3 years. Most were in the H&N region in paediatric patients with RMS. Cataracts (30.5%) were the most common, then musculoskeletal deformity (10.1%) and premature menopause (10.1%). Three paediatric patients (1-3 years at treatment) experienced secondary malignancy. Seven grade 4 toxicities occurred (1.6%), all in the H&N region and most in paediatric patients with RMS. Six related to eyes (cataracts, retinopathy, scleral disorder) or ears (hearing impairment).

CONCLUSIONS

This study is the largest to date for RMS and Ewing sarcoma, undergoing multimodality therapy including PBT. It demonstrates good local control, survival and acceptable toxicity rates.

Working in a UK national proton radiotherapy facility: the therapeutic radiographer perspective

The first national UK proton beam therapy centre opened at The Christie NHS Foundation Trust in 2018, which alongside University College London Hospitals NHS Foundation Trust (UCLH) proton beam therapy centre, is expected to treat approximately seven-hundred and fifty patients per year at service ramp up.

The aim of this editorial is to share with a wider audience the role of a Band 6 proton senior treatment radiographer working in a national NHS service and future developments of the service. Prior to the service being clinical, a range of processes were followed, including the creation of quality documents, departmental training and end-to-end testing, with the first patient receiving treatment in December 2018.

Proton senior radiographers are responsible for the delivery of safe and accurate radiotherapy and ensuring a smooth patient pathway, through a multi-collaborative team approach. Although there are key differences between proton and photon radiotherapy, the fundamental aspects, including radiation principles, governance and patient advice are the same. The training package for proton senior radiographers includes an individual local induction as part of the proton education and competency framework, which incorporates practical learning, including clinical supervision and workshops, plus audio-visual presentations and workbooks to complete.

Future developments of proton beam therapy include proton arc therapy and flash therapy, alongside educational developments, such as training the future workforce and advanced practice consultant radiographer roles. Shared learning through multi-collaboration of international proton beam therapy centres is crucial to improve care for future service users.

Particle Therapy: Clinical Applications and Biological Effects

Particle therapy is a developing area of radiotherapy, mostly involving the use of protons, neutrons and carbon ions for cancer treatment. The reduction of side effects on healthy tissues in the peritumoral area is an important advantage of particle therapy. In this review, we analyze state-of-the-art particle therapy, as compared to conventional photon therapy, to identify clinical benefits and specify the mechanisms of action on tumor cells. Systematization of published data on particle therapy confirms its successful application in a wide range of cancers and reveals a variety of biological effects which manifest at the molecular level and produce the particle therapy-specific molecular signatures. Given the rapid progress in the field, the use of particle therapy holds great promise for the near future.

Roadmap: helium ion therapy

Helium ion beam therapy for the treatment of cancer was one of several developed and studied particle treatments in the 1950s, leading to clinical trials beginning in 1975 at the Lawrence Berkeley National Laboratory. The trial shutdown was followed by decades of research and clinical silence on the topic while proton and carbon ion therapy made debuts at research facilities and academic hospitals worldwide. The lack of progression in understanding the principle facets of helium ion beam therapy in terms of physics, biological and clinical findings persists today, mainly attributable to its highly limited availability. Despite this major setback, there is an increasing focus on evaluating and establishing clinical and research programs using helium ion beams, with both therapy and imaging initiatives to supplement the clinical palette of radiotherapy in the treatment of aggressive disease and sensitive clinical cases. Moreover, due its intermediate physical and radio-biological properties between proton and carbon ion beams, helium ions may provide a streamlined economic steppingstone towards an era of widespread use of different particle species in light and heavy ion therapy. With respect to the clinical proton beams, helium ions exhibit superior physical properties such as reduced lateral scattering and range straggling with higher relative biological effectiveness (RBE) and dose-weighted linear energy transfer (LET_d) ranging from ∼4 keVμm^-1to ∼40 keVμm^-1. In the frame of heavy ion therapy using carbon, oxygen or neon ions, where LET_dincreases beyond 100 keVμm^-1, helium ions exhibit similar physical attributes such as a sharp lateral penumbra, however, with reduced radio-biological uncertainties and without potentially spoiling dose distributions due to excess fragmentation of heavier ion beams, particularly for higher penetration depths. This roadmap presents an overview of the current state-of-the-art and future directions of helium ion therapy: understanding physics and improving modeling, understanding biology and improving modeling, imaging techniques using helium ions and refining and establishing clinical approaches and aims from learned experience with protons. These topics are organized and presented into three main sections, outlining current and future tasks in establishing clinical and research programs using helium ion beams-A. Physics B. Biological and C. Clinical Perspectives.

Estimating the percentage of patients who might benefit from proton beam therapy instead of X-ray radiotherapy

OBJECTIVES

High-energy Proton Beam Therapy (PBT) commenced in England in 2018 and NHS England commissions PBT for 1.5% of patients receiving radical radiotherapy. We sought expert opinion on the level of provision.

METHODS

Invitations were sent to 41 colleagues working in PBT, most at one UK centre, to contribute by completing a spreadsheet. 39 responded: 23 (59%) completed the spreadsheet; 16 (41%) declined, arguing that clinical outcome data are lacking, but joined six additional site-specialist oncologists for two consensus meetings. The spreadsheet was pre-populated with incidence data from Cancer Research UK and radiotherapy use data from the National Cancer Registration and Analysis Service. 'Mechanisms of Benefit' of reduced growth impairment, reduced toxicity, dose escalation and reduced second cancer risk were examined.

RESULTS

The most reliable figure for percentage of radical radiotherapy patients likely to benefit from PBT was that agreed by 95% of the 23 respondents at 4.3%, slightly larger than current provision. The median was 15% (range 4-92%) and consensus median 13%. The biggest estimated potential benefit was from reducing toxicity, median benefit to 15% (range 4-92%), followed by dose escalation median 3% (range 0 to 47%); consensus values were 12 and 3%. Reduced growth impairment and reduced second cancer risk were calculated to benefit 0.5% and 0.1%.

CONCLUSIONS

The most secure estimate of percentage benefit was 4.3% but insufficient clinical outcome data exist for confident estimates. The study supports the NHS approach of using the evidence base and developing it through randomised trials, non-randomised studies and outcomes tracking.

ADVANCES IN KNOWLEDGE

Less is known about the percentage of patients who may benefit from PBT than is generally acknowledged. Expert opinion varies widely. Insufficient clinical outcome data exist to provide robust estimates. Considerable further work is needed to address this, including international collaboration; much is already underway but will take time to provide mature data.

A Novel Model and Infrastructure for Clinical Outcomes Data Collection and Their Systematic Evaluation for UK Patients Receiving Proton Beam Therapy

AIMS

To establish an infrastructure for sustainable, comprehensive data collection and systematic outcomes evaluation for UK patients receiving proton beam therapy (PBT).

MATERIALS AND METHODS

A Proton Outcomes Working Group was formed in 2014 to develop a national minimum dataset for PBT patients and to define a clinically integrated informatics solution for data collection. The Christie Proton Beam Therapy Centre formed its Proton Clinical Outcomes Unit in 2018 to collect, curate and analyse outcomes data prospectively for UK-treated patients and retrospectively for UK patients referred abroad for PBT since 2008 via the Proton Overseas Programme (POP).

RESULTS

A single electronic form (eForm) was developed to capture the agreed data, using a data tree approach including conditional logic: data items are requested once, further questions depend on previous answers and are sensitive to tumour site and patient pathway time point. Relevant data automatically populate other forms, saving time, prompting completeness of clinical assessments and ensuring data consistency. Completed eForm data populate the electronic patient record and generate individualised outputs, including consultation letters, treatment summary and surveillance plans, based on organs at risk irradiated, age and sex. All data regarding POP-treated patients are verified and migrated into the system, ensuring that patient data, whether overseas or UK treated, are consistently recorded. The eForm utilises a 'user friendly' web portal interface, the Clinical Web Portal, including clickable tables and infographics. Data items are coded to a universally recognised standard comparable with other data systems. Patient-reported outcomes are also integrated, highlighting significant toxicities and prompting a response. Outcomes data can be correlated with dosimetric DICOM data to support radiation dose modelling.

CONCLUSION

Outcomes data from both POP-treated and The Christie-treated patients support long-term care, allow evaluation of PBT efficacy and safety, assist future selection of PBT patients and support hypothesis generation for future clinical trials.

Who Will Benefit from Charged-Particle Therapy?

Charged-particle therapy (CPT) such as proton beam therapy (PBT) and carbon-ion radiotherapy (CIRT) exhibit substantial physical and biological advantages compared to conventional photon radiotherapy. As it can reduce the amount of radiation irradiated in the normal organ, CPT has been mainly applied to pediatric cancer and radioresistent tumors in the eloquent area. Although there is a possibility of greater benefits, high set-up cost and dearth of high level of clinical evidence hinder wide applications of CPT. This review aims to present recent clinical results of PBT and CIRT in selected diseases focusing on possible indications of CPT. We also discussed how clinical studies are conducted to increase the number of patients who can benefit from CPT despite its high cost.

The Promise of Proton Beam Therapy for Oesophageal Cancer: A Systematic Review of Dosimetric and Clinical Outcomes

AIMS

Due to its physical advantages over photon radiotherapy, proton beam therapy (PBT) has the potential to improve outcomes from oesophageal cancer. However, for many tumour sites, high-quality evidence supporting PBT use is limited. We carried out a systematic review of published literature of PBT in oesophageal cancer to ascertain potential benefits of this technology and to gauge the current state-of-the-art. We considered if further evaluation of this technology in oesophageal cancer is desirable.

MATERIALS AND METHODS

A systematic literature search of Medline, Embase, Cochrane Library and Web of Science using structured search terms was carried out. Inclusion criteria included non-metastatic cancer, full articles and English language studies only. Articles deliberating technical aspects of PBT planning or delivery were excluded to maintain a clinical focus. Studies were divided into two sections: dosimetric and clinical studies; qualitatively synthesised.

RESULTS

In total, 467 records were screened, with 32 included for final qualitative synthesis. This included two prospective studies with the rest based on retrospective data. There was heterogeneity in treatment protocols, including treatment intent (neoadjuvant or definitive), dose, fractionation and chemotherapy used. Compared with photon radiotherapy, PBT seemed to reduce dose to organs at risk, especially lung and heart, although not for all reported parameters. Toxicity outcomes, including postoperative complications, were reduced compared with photon radiotherapy. Survival outcomes were reported to be at least comparable with photon radiotherapy.

CONCLUSION

There is a paucity of high-quality evidence supporting PBT use in oesophageal cancer. Wide variation in intent and treatment protocols means that the role and 'gold-standard' treatment protocol are yet to be defined. Current literature suggests significant benefit in terms of toxicity reduction, especially in the postoperative period, with comparable survival outcomes. PBT in oesophageal cancer holds significant promise for improving patient outcomes but requires robust systematic evaluation in prospective studies.

Online learning in proton radiation therapy: the future in the post-Covid-19 pandemic era?

Objective:

The Covid-19 pandemic placed unprecedented strain on medical education and led to a vast increase in online learning. Subsequently, the Christie International Proton School moved from face-to-face to online. Delegate feedback and current literature were studied to determine benefits, challenges, and potential solutions, for online proton therapy education.

Methods:

The course was converted to a 6-week online course with twice weekly 2-h sessions. Feedback was studied pre-, during-, and post-course regarding demographics, learning objectives, proton therapy knowledge, ease of engagement, technical difficulties, and course format. Statistical analyses were performed for proton therapy knowledge pre- and post-course.

Results:

An increase in delegate attendance was seen with increased international and multidisciplinary diversity. Learner objectives included treatment planning, clinical applications, physics, and centre development. Average learner reported scores of confidence in proton therapy knowledge improved significantly from 3, some knowledge, to 4, adequate knowledge after the course (p<0.0001). There were minimal reported difficulties using the online platform, good reported learner engagement, and shorter twice weekly sessions were reported conducive for learning. Recordings for asynchronous learning addressed time zone difficulties.

Conclusion:

The obligatory switch to online platforms has catalysed a paradigm shift towards online learning with delegates reporting educational benefit. We propose solutions to challenges of international online education, and a pedagogical model for online proton therapy education.

Advances in knowledge:

Online education is an effective method to teach proton therapy to international audiences. The future of proton education includes a hybrid of online and practical face-to-face learning depending on the level of cognitive skill required.

Online learning in proton radiation therapy: the future in the post-Covid-19 pandemic era?

OBJECTIVE

The Covid-19 pandemic placed unprecedented strain on medical education and led to a vast increase in online learning. Subsequently, the Christie International Proton School moved from face-to-face to online. Delegate feedback and current literature were studied to determine benefits, challenges, and potential solutions, for online proton therapy education.

METHODS

The course was converted to a 6-week online course with twice weekly 2-h sessions. Feedback was studied pre-, during-, and post-course regarding demographics, learning objectives, proton therapy knowledge, ease of engagement, technical difficulties, and course format. Statistical analyses were performed for proton therapy knowledge pre- and post-course.

RESULTS

An increase in delegate attendance was seen with increased international and multidisciplinary diversity. Learner objectives included treatment planning, clinical applications, physics, and centre development. Average learner reported scores of confidence in proton therapy knowledge improved significantly from 3, some knowledge, to 4, adequate knowledge after the course (p<0.0001). There were minimal reported difficulties using the online platform, good reported learner engagement, and shorter twice weekly sessions were reported conducive for learning. Recordings for asynchronous learning addressed time zone difficulties.

CONCLUSION

The obligatory switch to online platforms has catalysed a paradigm shift towards online learning with delegates reporting educational benefit. We propose solutions to challenges of international online education, and a pedagogical model for online proton therapy education.

ADVANCES IN KNOWLEDGE

Online education is an effective method to teach proton therapy to international audiences. The future of proton education includes a hybrid of online and practical face-to-face learning depending on the level of cognitive skill required.

Patient and Public Involvement Refines the Design of ProtOeus: A Proposed Phase II Trial of Proton Beam Therapy in Oesophageal Cancer

BACKGROUND

Neoadjuvant chemoradiotherapy for oesophageal cancer significantly improves overall survival but is associated with severe post-operative complications. Proton beam therapy may reduce these toxicities by sparing normal tissues compared with standard radiotherapy. ProtOeus is a proposed randomised phase II study of neoadjuvant chemoradiotherapy in oesophageal cancer that compares proton beam therapy to standard radiotherapy techniques. As proton beam therapy services are often centralised in academic centres in major cities, proton beam therapy trials raise distinct challenges including patient acceptance of travelling for proton beam therapy, coordination of treatments with local centres and ensuring equity of access for patients.

METHODS

Focus groups were held early in the trial development process to establish patients' views on the trial proposal. Topics discussed include perception of proton beam therapy, patient acceptability of the trial pathway and design, patient-facing materials, and common clinical scenarios. Focus groups were led by the investigators and facilitated by patient involvement teams from the institutions who are involved in this research. Responses for each topic were analysed, and fed back to the trial's development group.

RESULTS

Three focus groups were held in separate locations in the UK (Manchester, Cardiff, Wigan). Proton beam therapy was perceived as superior to standard radiotherapy making the trial attractive. Patients felt strongly that travel costs should be reimbursed to ensure equity of access to proton beam therapy. They were very supportive of a shorter treatment schedule and felt that toxicity reduction was the most important endpoint.

DISCUSSION AND CONCLUSIONS

Incorporating patient views early in the trial development process resulted in significant trial design refinements including travel/accommodation provisions, choice of primary endpoint, randomisation ratio and fractionation schedule. Focus groups are a reproducible and efficient method of incorporating the patient and public voice into research.

Heavy charged particle beam therapy and related new radiotherapy technologies: The clinical potential, physics and technical developments required to deliver benefit for patients with cancer

In the UK, one in two people will develop cancer during their lifetimes and radiotherapy (RT) plays a key role in effective treatment. High energy proton beam therapy commenced in the UK National Health Service in 2018. Heavier charged particles have potential advantages over protons by delivering more dose in the Bragg peak, with a sharper penumbra, lower oxygen dependence and increased biological effectiveness. However, they also require more costly equipment including larger gantries to deliver the treatment. There are significant uncertainties in the modelling of relative biological effectiveness and the effects of the fragmentation tail which can deliver dose beyond the Bragg peak. These effects need to be carefully considered especially in relation to long-term outcomes.In 2019, a group of clinicians, clinical scientists, engineers, physical and life scientists from academia and industry, together with funding agency stakeholders, met to consider how the UK should address new technologies for RT, especially the use of heavier charged particles such as helium and carbon and new modes of delivery such as FLASH and spatially fractionated radiotherapy (SFRT).There was unanimous agreement that the UK should develop a facility for heavier charged particle therapy, perhaps constituting a new National Ion Research Centre to enable research using protons and heavier charged particles. Discussion followed on the scale and features, including which ions should be included, from protons through helium, boron, and lithium to carbon, and even oxygen. The consensus view was that any facility intended to treat patients must be located in a hospital setting while providing dedicated research space for physics, preclinical biology and clinical research with beam lines designed for both in vitro and in vivo research. The facility should to be able to investigate and deliver both ultra-high dose rate FLASH RT and SFRT (GRID, minibeams etc.). Discussion included a number of accelerator design options and whether gantries were required. Other potential collaborations might be exploited, including with space agencies, electronics and global communications industries and the nuclear industry.In preparation for clinical delivery, there may be opportunities to send patients overseas (for 12C or 4He ion therapy) using the model of the National Health Service (NHS) Proton Overseas Programme and to look at potential national clinical trials which include heavier ions, FLASH or SFRT. This could be accomplished under the auspices of NCRI CTRad (National Cancer Research Institute, Clinical and Translational Radiotherapy Research Working Group).The initiative should be a community approach, involving all interested parties with a vision that combines discovery science, a translational research capability and a clinical treatment facility. Barriers to the project and ways to overcome them were discussed. Finally, a set of different scenarios of features with different costs and timelines was constructed, with consideration given to the funding environment (prer-Covid-19) and need for cross-funder collaboration.