Global Radiotherapy: Current Status and Future Directions-White Paper

Phycocyanin-based multifunctional microspheres for treatment of infected radiation-induced skin injury

Radiation therapy is a primary modality for cancer treatment; however, it often leads to various degrees of skin injuries, ranging from mild rashes to severe ulcerations, for which no effective treatments are currently available. In this study, a multifunctional microsphere (PC@CuS-ALG) was synthesized by encapsulating phycocyanin-templated copper sulfide nanoparticles (PC@CuS) within alginate (ALG) using microfluidic technology. Phycocyanin, a natural protein derived from microalgae, shows abilities to scavenge reactive oxygen species, repair radiation-induced damage to skin cells, and ameliorate macrophage-related inflammatory responses. CuS contributes to photothermal conversion efficiency and exhibits antibacterial properties. The microspheres facilitate the sustained release of PC@CuS, retain moisture at the wound site, and provide a supportive environment for cell migration and growth. In a mouse model of infected radiation-induced skin injury, PC@CuS-ALG exhibited antibacterial and wound healing effects, resulting in accelerated epidermal tissue regeneration, increased thickness and maturation of dermal granulation tissue, and an ameliorated inflammatory response. This study presents a novel, effective, and safe approach for treating radiation-induced skin injuries complicated by bacterial infection.

Beam collimation and filtration optimization for a novel orthovoltage radiotherapy system

BACKGROUND

The inaccessibility of clinical linear accelerators in low- and middle-income countries creates a need for low-cost alternatives. Kilovoltage (kV) x-ray tubes have shown promise as a source that could meet this need. However, performing radiotherapy with a kV x-ray tube has numerous difficulties, including high skin dose, rapid dose fall-off, and low dose rates. These limitations create a need for highly effective beam collimation and filtration.

PURPOSE

To improve the treatment potential of a novel kV x-ray system by optimizing an iris collimator and beam filtration using Bayesian techniques and Monte Carlo (MC) simulations.

METHODS

The Kilovoltage Optimized AcceLerated Adaptive therapy system's current beam configuration consists of a 225 kVp x-ray tube, a 12-leaflet tungsten iris collimator, and a 0.1 mm copper filter. A Bayesian optimization was performed for the large and small focal spot sizes of the kV x-ray tube source at 220 kVp using TopasOpt, an open-source library for optimization in TOPAS. Collimator thickness, copper filter thickness, source-to-collimator distance (SCD), and source-to-surface distance (SSD) were the variables considered in the optimization. The objective function was designed to maximize the dose rate and the dose at a depth of 5 cm while minimizing the beam penumbra width and the out-of-field dose (OFD), all evaluated in a water phantom. Post-optimization, the optimal beam configuration was simulated and compared to the existing configuration.

RESULTS

The optimal collimation setup consisted of 2.5 mm thick tungsten leaflets for the iris collimator and a 350 mm SSD for both focal spot sizes. The optimal copper filtration was 0.22 mm for the large focal spot and 0.15 mm for the small focal spot, with a SCD of 148.5 mm for the large focal spot and 125.8 mm for the small focal spot. For the large focal spot, the surface dose rate decreased by 9.4%, while the PDD at 5cm depth (PDD 5 c m $\text{PDD}_{5\textnormal {cm}}$ ) increased by 7.7% compared to the existing iris collimator. Additionally, the surface beam penumbra width was reduced by 31.3%, and no significant changes in the OFD were observed. For the small focal spot, the surface dose rate for the new collimator increased by 3.7% and thePDD 5 c m $\text{PDD}_{5\textnormal {cm}}$ increased by 5.3%, with no statistically significant changes in the beam penumbra width or OFD.

CONCLUSION

The optimal beam collimation and filtration for both x-ray tube focal spot sizes of a kV radiotherapy system was determined using Bayesian optimization and MC simulations and resulted in improved dose distributions.

An ultra-high dose rate Bragg peak tracking technique provides more affordable proton radiotherapy for cancer patients: From principle to experimental validation

PURPOSE

This work aims to experimentally validate a novel cost-effective solution for achieving both conventional dose-rate and ultra-high dose rate (UHDR) deliveries in pencil beam scanning proton therapy.

METHODS

A proton therapy delivery solution was previously developed by our group using only a single pristine Bragg peak of the highest energy proton beams from a cyclotron. This approach streamlines upstream beam modifiers, including energy degrader, selection and focusing systems, while utilizing of universal range shifters (URS) and range compensators (RCs) to preserve high beam transmission efficiency for UHDR beam delivery. It achieves the Bragg peak tracking and target dose conformity, making it potentially suitable for FLASH radiation therapy. In the current study, we highlighted the realization of the solution by using URS and customized beam-specific RCs via simulation in an in-house treatment planning software (TPS) which is then fabricated by a 3D printer, facilitating precise beam shaping and Bragg peak tracking. Experimental validation of this method was conducted using a clinical proton system to showcase a practical solution that can be translated into realistic operation. Both dose and dose rate were measured and compared to treatment planning results.

RESULTS

The proton convolution superposition (PCS) dose calculation was benchmarked by the Monte Carlo calculation. Matrixx PT measured the delivered dose in the uniform and head-neck (HN) phantom, and the gamma passing rates were > 99 % in the water phantom. The gamma rate was > 98 % for the HN phantom for this distal tracking method. The measured dose difference between the TPS and HN phantom was < 2 %. The implementation of a high temporal resolution strip ion chamber detector array enabled accurate measurement of the spot time structure, facilitating 3D dose rate reconstruction across various beam currents.

CONCLUSION

The experimental validation successfully demonstrated the dosimetric accuracy and robustness of this proposed delivery method. The employment of the Bragg peak tracking method holds great promise for reducing treatment delivery costs for future UHDR and conventional dose rate proton radiation therapy, ultimately benefiting a larger population of patients.

Evaluating Adjuvant Radiation Therapy for Grade 2 Meningioma: A Multi-Institutional Analysis

BACKGROUND AND OBJECTIVES

Grade 2 meningiomas are associated with variable rates of local recurrence, and the role of adjuvant radiation therapy (RT) remains debated.

METHODS

This was a multi-institutional retrospective cohort study including all adult patients with newly diagnosed and previously untreated grade 2 meningioma treated at Mass General Brigham hospitals from 2006 to 2020. Cox proportional-hazards modeling was used to analyze the impact of adjuvant RT on progression-free survival (PFS).

RESULTS

A total of 429 patients with grade 2 meningioma were included (median age 59.7 years, 61.5% female). Gross total resection (GTR) was achieved in 298 cases (69.5%). Among 284 cases with quantified Ki67 proliferation indices, the median proliferation indice was 10.0% (IQR 6.7%-15%). In total, 18.8% cases had adjuvant RT after GTR and 48.9% of cases had adjuvant RT after subtotal resection (STR). The median follow-up was 5.2 years. Adjuvant RT was not associated with PFS after GTR (hazard ratio [HR] 0.85; 95% CI 0.48-1.52) but was associated with improved PFS after STR (HR 0.54; 95% CI 0.31-0.94). These findings remained consistent after adjusting for age, sex, tumor location, and tumor size. Adjuvant RT was associated with improved PFS for cases with Ki67 index equal to or over 10% (HR 1.89; 95% CI 1.05-3.60; P = .034), but not below 10% (HR 0.94; 95% 0.47-1.67; P = .93).

CONCLUSION

Adjuvant RT for grade 2 meningioma may reduce tumor progression for patients with Ki67 index ≥10% or after STR and should be considered as part of a multidisciplinary approach to postoperative management. Routine use of adjuvant RT after GTR was not associated with improved PFS, for which avoidance of RT after GTR should be considered to minimize potential treatment-associated morbidity. This study supports selective use of adjuvant RT, optimizing patient outcomes by balancing the benefits of reduced progression against potential morbidities of treatment.

The road to successful implementation of innovation in radiotherapy: A research-based implementation protocol

BACKGROUND AND PURPOSE

Radiotherapy (RT) is rapidly advancing, yet only 50 % of innovations are implemented promptly. Despite the availability of Implementation Science (ImpSci) theories, models, and frameworks (TMFs), a theory-practice gap persists in effectively applying these insights in RT clinical practice. This study aims to develop a consensus-based implementation protocol for RT innovations using validated ImpSci knowledge.

MATERIAL AND METHODS

A literature review of TMFs (May-August 2023) and 20 semi-structured interviews with Dutch RT professionals (August-December 2023) identified key RT components for implementation. These insights informed a draft RT implementation protocol, which was refined through a three-round international Delphi study (March-September 2024) involving 11 RT and 5 ImpSci experts. Consensus was determined using a 5-point Likert scale, analysing medians, interquartile ranges (IQRs), and percentage scoring.

RESULTS

The Knowledge-to-Action (KTA) Framework and input from expert interviews were used to draft the protocol. Delphi response rates were 100 %, 93.8 %, and 88.9 % across rounds. In round 1, 88.9 % of elements achieved consensus (median = 4.0, IQR = 0.0-1.3); only the application of a prediction model for timely implementation (step 3c) needed revision after rounds 1 and 2. In round 3, also for step 3c consensus was reached (median = 4.0, IQR = 0.3). The protocol includes defining innovation types, stakeholder analysis, tailored implementation strategies, and a phased evaluation plan to ensure sustainability.

CONCLUSION

This is the first consensus-based RT innovation implementation protocol, addressing the theory-practice gap with a structured clinical approach. Future research should validate the protocol and assess the impact of preparation on implementation success.

The socioeconomic burden of cervical cancer and its implications for strategies required to achieve the WHO elimination targets

INTRODUCTION

Cervical cancer is almost entirely preventable by vaccination and screening. Population-based vaccination and screening programs are effective and cost effective, but millions of people do not have access to these programs, causing immense suffering. The WHO Global Strategy for the elimination of cervical cancer as a public health problem calls for countries to meet ambitious vaccination, screening, and treatment targets.

AREAS COVERED

Epidemiological evidence indicates marked socioeconomic gradients in the burden of cervical cancer and vaccination, screening, and treatment coverage. The unacceptable socioeconomic burden of cervical cancer is largely a function of inequitable access to these programs. We discuss these inequities, and highlight strategies enabled by new evidence and technology. Single dose HPV vaccination, HPV-based screening, and the rapidly moving technology landscape have enabled task-shifting, innovation in service delivery and the possibility of scale. Equitable access to optimal care for the treatment of invasive cancers remains a challenge.

EXPERT OPINION

Cervical cancer can be eliminated equitably. It will require global political will, sustained public and private investment, and community leadership to safely and sustainably embed proven tools, technology and infrastructure in local health and knowledge systems.

Detection of an internal density change in an anthropomorphic head phantom via tracking of charged nuclear fragments in carbon-ion radiotherapy

BACKGROUND

Carbon-ion radiotherapy provides steep dose gradients that allow the simultaneous application of high tumor doses as well as the sparing of healthy tissue and radio-sensitive organs. However, even small anatomical changes may have a severe impact on the dose distribution because of the finite range of ion beams.

PURPOSE

An in-vivo monitoring method based on secondary-ion emission could potentially provide feedback about the patient anatomy and thus the treatment quality. This work aims to prove that a clinically relevant anatomical change in an anthropomorphic head phantom may be detected via charged-fragment tracking during a treatment fraction.

METHODS

A clinically representative carbon-ion treatment plan was created for a skull-base tumor in an anthropomorphic head phantom. In order to imitate an inter-fractional anatomical change - for example, through tissue swelling or mucous accumulation - a piece of silicone was inserted into the nasopharynx. Fragment distributions with and without the silicone insert were subsequently acquired with a mini-tracker made of four hybrid silicon pixel detectors. Experimental irradiations were carried out at the Heidelberg Ion Beam Therapy Centre (HIT, Germany). FLUKA Monte Carlo simulations were performed to support the interpretation of the experimental results.

RESULTS

It was found that the silicone causes a significant change in the fragment emission that was clearly distinguishable from statistical fluctuations and setup uncertainties. Two regions of fragment loss were observed upstream and downstream of the silicone with similar amplitude in both the measurement and the simulation. Monte Carlo simulations showed that the observed signature is a consequence of a complex interplay of fragment production, scattering, and absorption.

CONCLUSIONS

Carbon-ion therapy monitoring with charged nuclear fragments was shown to be capable of detecting clinically relevant density changes in an anthropomorphic head phantom under realistic clinic-like conditions. The complexity of the observed signal requires the development of advanced analysis techniques and underscores the importance of Monte Carlo simulations. The findings have strong implications for the ongoing InViMo clinical trial at HIT, which investigates the feasibility of secondary-ion monitoring for skull-base cancer patients.

Initial characterization of a novel dual-robot orthovoltage radiotherapy system

Purpose:Adequate access to radiotherapy is a critical global concern affecting low-resource settings such as low- and middle-income countries and rural regions. We propose to reduce this disparity by developing a novel low-cost radiotherapy device that treats using non-coplanar techniques and a 225 kVp x-ray tube.Methods:This novel device has been preliminarily characterized spectrally, via spectrometer measurements, dosimetrically, via percent depth dose curves and 2D profiles, and geometrically, via a coplanar star-shot. Dosimetric and geometric evaluations were then combined by performing a proof of workflow of the KOALA system. Monte Carlo simulations were run in TOPAS to validate dosimetric measurements and the proof of workflow measurement.Results:Spectral results showed excellent agreement between measured and modelled spectra. Dose errors of  < 2% were achieved for PDD curves. Full width at half maximum values for the 2D profiles were, on average, 0.95 mm higher in simulation compared to film. A star-shot test demonstrated the high geometrical accuracy of the system with a 0.3 mm diameter wobble circle. Finally, a mean absolute percent error of 5  ±  5% (1σ) was measured for the proof of workflow test.Conclusions:This initial characterization showcased the strengths and weaknesses of the KOALA system, with excellent isocenter precision and depth dose accuracy while lacking dosimetric accuracy in the 2D profiles. Further improvements on the source-to-collimator distance and treatment couch material can be made to improve the accuracy of a Monte Carlo model of the KOALA system.

Development and implementation of a 3d-HDR brachytherapy program for cervical cancer in a sub-Saharan African centre

BACKGROUND

Cervical cancer is the second most common cancer among women in Nigeria where, the gap between need for, and access to, radiation therapy including brachytherapy is significant. This report documents the implementation of the first three-dimensional high-dose-rate (3D-HDR) brachytherapy service for cervical cancer in Nigeria.

PURPOSE

This report details the steps taken to implement the 3D-HDR brachytherapy program, the challenges faced, and the adaptive strategies employed to overcome them. Our objective is to provide a guide for teams and centers in similar resource-restricted settings to implement 3D-HDR brachytherapy services, by leveraging our shared experience and lessons learned.

METHOD AND METERIALS

The implementation process required investment in infrastructure: creating a dedicated brachytherapy suite equipped with modern technology; and human capital: conducting both virtual and hands-on training for staff; and involving international experts during the initial treatment phases. Quality assurance protocols were established to ensure the accuracy and safety of treatments. Key adaptations included extensive remote training, international experts flying in for the initiation phase, and preemptively re-ordering the radioisotope to prevent delays.

RESULTS

The 3D-HDR brachytherapy program was successfully implemented, with five cases treated in the first 2 months despite challenges such as high equipment costs, expertise and proficiency needs, and source replacement delays. Continuous training and quality assurance measures ensured the program's sustainability and effectiveness.

CONCLUSIONS

Implementing a 3D-HDR brachytherapy program in a system with restricted resources is possible with thorough planning, flexible strategies, and adaptive measures. We document our experience to provide insights for other institutions aiming to establish similar programs. Collaboration and innovative financial strategies are essential for ensuring sustainable access to cancer treatment in the region. Strategies such as remote training and proactive resource management, are critical for overcoming implementation barriers.

Artificial intelligence for response prediction and personalisation in radiation oncology

Artificial intelligence (AI) systems may personalise radiotherapy by assessing complex and multifaceted patient data and predicting tumour and normal tissue responses to radiotherapy. Here we describe three distinct generations of AI systems, namely personalised radiotherapy based on pretreatment data, response-driven radiotherapy and dynamically optimised radiotherapy. Finally, we discuss the main challenges in clinical translation of AI systems for radiotherapy personalisation.

Perceived barriers and facilitators affecting utilisation of radiation therapy services: Scoping review findings - Patient and department level influences

Existing evidence supports the benefits of radiation therapy (RT) for cancer patients however, it is underutilised. This scoping review aims to synthesise the current literature investigating patient and department level barriers and facilitators influencing the utilisation trends of RT. A systematic search strategy was developed to identify articles dated from 1993 to 2023. Four online databases (Medline, Embase, Scopus and CINAHL) were searched using key words. Eligible studies needed to report outcomes related to barriers and facilitators influencing utilisation of RT. Data was extracted and categorised into health professional, patient, and department level influences. The review resulted in 340 included studies with 298 (88 %) studies reporting on patient influences. More than half of these studies (n = 164; 55 %) reported accessibility concerns including distance and travel burden. Patient acceptability was reported in 88 (30 %) studies, patient affordability in 138 (46 %) studies, patient knowledge, and education in 92 (31 %) studies and patient health and demographics in 235 (79 %) studies. Of the department level influence papers (n = 242, 71 %), department availability such as infrastructure, staffing and waitlists were reported in 167 (69 %) papers. Department adequacy, including the quality, reputation and technology suitability of departments was reported in 60 (25 %) papers. Clinical pathway use was reported in 107 (44 %) papers. This scoping review identifies the broad range of patient and department level influences and facilitators affecting the global utilisation of RT. Recognition of such influences reducing access to RT will inform proposed interventions or educational strategies to overcome and address such barriers.

Irradiation-responsive PRDM10-DT modulates the angiogenic response in human NSCLC cells in an SP1-dependent manner via the miR-663a/TGF-β1 axis

BACKGROUND

Photon radiation has been shown to stimulate the secretion of radioresistant factors from tumor cells, ultimately promoting tumor angiogenesis and metastasis. On the other hand, heavy-ion radiotherapy has been demonstrated to control tumor angiogenesis and metastasis levels. The molecular mechanisms responsible for the different angiogenic responses to photon and heavy-ion irradiation are not fully understood. This study aims to explore the irradiation-responsive genes related to tumor angiogenesis and reveal the regulatory effect.

METHODS

In order to clarify the potential regulatory mechanisms of tumor angiogenesis after X-ray or carbon ion (C-ion) irradiation, we performed RNA-sequencing (RNA-seq), as well as bioinformatics, public database analysis, Western blotting, immunohistochemistry, and immunofluorescence.

RESULTS

In this study, we identified the long intergenic noncoding RNA PRDM10 divergent transcript (PRDM10-DT), which was responsive to X-rays but not carbon ions. Mechanistically, PRDM10-DT triggers tumor angiogenesis by upregulating the TGF-β1/VEGF signaling pathway through its competitive binding to miR-663a. Additionally, the transcription factor SP1 facilitated the transcription of PRDM10-DT by binding to its promoter region. It's notable that the DNA-binding activity of SP1 was enhanced by reactive oxygen species (ROS). The knockdown of either PRDM10-DT or SP1 effectively inhibited NSCLC angiogenesis and metastasis.

CONCLUSION

These results illustrate the proangiogenic function of the PRDM10-DT/miR-663a/TGF-β1 axis and reveal the regulatory role of ROS and SP1 in the upstream response to radiation, with differential ROS production mediating the differential angiogenesis levels after X-ray and C-ion irradiation. Our findings suggest the potential of PRDM10-DT as a nucleic acid biomarker after radiotherapy and that targeting this gene could be a therapeutic strategy to counteract angiogenesis in NSCLC radiotherapy.

Evolution and Recent Radiation Therapy Advancement in Uganda: A Precedent on How to Increase Access to Quality Radiotherapy Services in Low- and Middle-Income Countries

The evolution of radiation therapy in Uganda has been a journey marked by significant milestones and persistent challenges. Since the inception of radiotherapy services in 1988-1989, there has been a concerted effort to enhance cancer treatment services. The early years were characterized by foundational developments, such as the installation of the first teletherapy units, low-dose-rate brachytherapy units, and conventional simulators, and the recognition of radiation oncologists and medical physicist professionals laid the groundwork for radiotherapy treatment modalities. With more support from the International Atomic Energy Agency, the acquisition of dosimetry equipment, treatment planning systems, and additional professional training signaled a new era in the fight against cancer. As we entered the second decade of the millennium, the Uganda Cancer Institute (UCI) witnessed a progression in sophisticated radiotherapy services, including high-dose-rate brachytherapy, initiation of intensity modulated radiation therapy (IMRT)/volumetric modulated arc therapy (VMAT), and use of artificial intelligence. These advancements improved the efficiency/precision of treatments and the time patients spent undergoing therapy. Around the second decade of radiotherapy services, about 600 new patients with cancer were annually treated compared with about 2,600 in 2023. Currently, an average of 1,440 brachytherapy insertions are done annually compared with 300 insertions for the first 20 years. Despite the technological strides, the UCI faced numerous obstacles, including limited equipment, knowledge gaps in appropriate tumor/organs at risk segmentations, treatment planning, and protocols. However, international support and collaboration efforts have led to significant improvement in the precision and effectiveness of treatments. Currently, about 51% of all patients are treated with image-guided techniques-IMRT/VMAT (42%) and three-dimensional conformal radiation treatment (10%). The Government has commenced the decentralization of radiotherapy services to other regions. This review can be a learning lesson for the more than 25 countries in Africa and other low-middle-income countries globally that do not have access to radiotherapy and/or are in the process of starting such facilities.

Towards melanoma in situ vaccination with multiple ultra-narrow X-ray beams

Despite the recent progress, current treatment modalities are not able to eradicate cancer. We show that Microbeam Radiotherapy (MRT), an innovative type of Spatially Fractionated Radiotherapy, can control murine melanoma by activating the host's own immune system. The beneficial effects are very pronounced in comparison to uniform radiotherapy traditionally employed in the clinic. Our results show that MRT increased antigen presentation, activating Cytotoxic T Lymphocytes (CTLs) which are essential to MRT's treatment efficacy in melanoma. Depletion of CTLs abrogated treatment response. Multiplex nucleic acid hybridization technology revealed key features of lymphocyte populations such as proliferation, differentiation, and ligand-receptor interactions. In addition, CTLs were shown to be essential for locoregional metastatic control and systemic abscopal effects confirmed by activation of antigen presenting cells and CTL trafficking in the tumour-draining lymph nodes. MRT also showed a synergistic effect with immunotherapy. Overall, MRT induces a robust antitumour immune response, acting like an in situ vaccination, which could be exploited to treat a variety of treatment-resistant malignancies.

ASPRONET: A facilitated online education project for radiation therapists in the Asia-Pacific region

In 2019, the International Atomic Energy Agency approved a technical co-operation project, aimed at supporting clinical decision making and continuing professional education of radiation oncologists, medical physicists and radiation therapists (RTs) in Low-and-Middle Income Countries (LMICs) in the Asia Pacific region. From this, the Asia-Pacific Radiation Oncology Network (ASPRONET) was formed in 2020. An RT co-ordination group administered 16 online, one-hour seminars between December 2021 and November 2023 for an RT audience. Analysis of online registration and attendance data from each seminar was used to co-ordinate group review meetings, improve seminar proceedings, and promote attendance and engagement. 772 attendees from 20 different countries were recorded in total across the seminars. Gathered data and observations indicated the success of the seminars and supported their continuation.

Access to diagnostic imaging and radiotherapy technologies for patients with cancer in the Baltic countries, eastern Europe, central Asia, and the Caucasus: a comprehensive analysis

BACKGROUND

Only 10-40% of patients with cancer in low-income and middle-income countries were able to access curative or palliative radiotherapy in 2015. We aimed to assess the current status of diagnostic imaging and radiotherapy services in the Baltic countries, eastern Europe, central Asia, and the Caucasus by collecting and analysing local data.

METHODS

This Access to Radiotherapy (ART) comprehensive analysis used data from 12 countries: the three Baltic countries (Estonia, Latvia, and Lithuania), two countries in eastern Europe (Moldova and Ukraine), four countries in central Asia (Kazakhstan, Kyrgyzstan, Tajikistan, and Uzbekistan), and three countries in the Caucasus (Armenia, Azerbaijan, and Georgia), referred to here as the ART countries. We were not able to obtain engagement from Turkmenistan. The primary outcome was to update the extent of shortfalls in the availability of diagnostic imaging and radiotherapy technologies and radiotherapy human resources for patients with cancer in former Soviet Union countries. Following the methods of previous similar studies, we developed three questionnaires-targeted towards radiation oncologists, regulatory authorities, and researchers-requesting detailed information on the availability of these resources. Authors from participating countries sent two copies of the appropriate questionnaire to each of 107 identified institutions and coordinated data collection at the national level. Questionnaires were distributed in English and Russian and responses in both languages were accepted. Two virtual meetings held on May 30 and June 1, 2022, were followed by an in-person workshop held in Almaty, Kazakhstan, in September, 2022, attended by representatives from all participating countries, to discuss and further validate the data submitted up to this point. The data were collected on a dedicated web page, developed by the International Cancer Expert Corps, and were then extracted and analysed.

FINDINGS

Data were collected between May 10 and Nov 30, 2022. 81 (76%) of the 107 institutions contacted, representing all 12 ART countries, submitted 167 completed questionnaires. The Baltic countries, which are defined as high-income countries, had more diagnostic imaging equipment and radiotherapy human resources (eg, Latvia [1·74] and Lithuania [1·47] have a much higher number of radiation oncologists per 100 000 population than the other ART countries, all of which had <1 radiation oncologist per 100 000 population) and greater radiotherapy technological capacities (higher numbers of linear accelerators and, similar to Georgia, high total external beam radiotherapy capacity) than the other ART countries, as well as high cancer detection rates (Latvia 311 cases per 100 000 population, Lithuania 292, and Estonia 288 vs, for example, 178 in Armenia, 144 in Ukraine, and 72 in Kazakhstan) and low cancer mortality-to-cancer incidence ratios (Estonia 0·43, Latvia 0·49, and Lithuania 0·48; lower than all but Kazakhstan [0·41]). The highest cancer mortality-to-cancer incidence ratios were reported by Moldova (0·71) and Georgia (0·74).

INTERPRETATION

Our findings show that the number of cancer cases, availability of diagnostic imaging equipment, radiation oncologists and radiotherapy capacity, and cancer mortality-to-cancer incidence ratios all vary substantially across the countries studied, with the three high-income, well resourced Baltic countries performing better in all metrics than the included countries in eastern Europe, central Asia, and the Caucasus. These data highlight the challenges faced by many countries in this study, and might help to justify increased investment of financial, human, and technological resources, with the aim to improve cancer treatment outcomes.

FUNDING

US Department of Energy's National Nuclear Security Administration's Office of Radiological Security.

Radiotherapy and theranostics: a Lancet Oncology Commission

Following on from the 2015 Lancet Oncology Commission on expanding global access to radiotherapy, Radiotherapy and theranostics: a Lancet Oncology Commission was created to assess the access and availability of radiotherapy to date and to address the important issue of access to the promising field of theranostics at a global level. A marked disparity in the availability of radiotherapy machines between high-income countries and low-income and middle-income countries (LMICs) has been identified previously and remains a major problem. The availability of a suitably trained and credentialled workforce has also been highlighted as a major limiting factor to effective implementation of radiotherapy, particularly in LMICs. We investigated initiatives that could mitigate these issues in radiotherapy, such as extended treatment hours, hypofractionation protocols, and new technologies. The broad implementation of hypofractionation techniques compared with conventional radiotherapy in prostate cancer and breast cancer was projected to provide radiotherapy for an additional 2·2 million patients (0·8 million patients with prostate cancer and 1·4 million patients with breast cancer) with existing resources, highlighting the importance of implementing new technologies in LMICs. A global survey undertaken for this Commission revealed that use of radiopharmaceutical therapy-other than 131I-was highly variable in high-income countries and LMICs, with supply chains, workforces, and regulatory issues affecting access and availability. The capacity for radioisotope production was highlighted as a key issue, and training and credentialling of health professionals involved in theranostics is required to ensure equitable access and availability for patient treatment. New initiatives-such as the International Atomic Energy Agency's Rays of Hope programme-and interest by international development banks in investing in radiotherapy should be supported by health-care systems and governments, and extended to accelerate the momentum generated by recognising global disparities in access to radiotherapy. In this Commission, we propose actions and investments that could enhance access to radiotherapy and theranostics worldwide, particularly in LMICs, to realise health and economic benefits and reduce the burden of cancer by accessing these treatments.

Global Workforce and Access: Demand, Education, Quality

There has long existed a substantial disparity in access to radiotherapy globally. This issue has only been exacerbated as the growing disparity of cancer incidence between high-income countries (HIC) and low and middle-income countries (LMICs) widens, with a pronounced increase in cancer cases in LMICs. Even within HICs, iniquities within local communities may lead to a lack of access to care. Due to these trends, it is imperative to find solutions to narrow global disparities. This requires the engagement of a diverse cohort of stakeholders, including working professionals, non-governmental organizations, nonprofits, professional societies, academic and training institutions, and industry. This review brings together a diverse group of experts to highlight critical areas that could help reduce the current global disparities in radiation oncology. Advancements in technology and treatment, such as artificial intelligence, brachytherapy, hypofractionation, and digital networks, in combination with implementation science and novel funding mechanisms, offer means for increasing access to care and education globally. Common themes across sections reveal how utilizing these new innovations and strengthening collaborative efforts among stakeholders can help improve access to care globally while setting the framework for the next generation of innovations.

Low-dose radiation promotes high-fat diet-induced atherosclerosis by activating cGAS signal pathway

BACKGROUND

Atherosclerosis (AS) is the most prevalent cardiovascular disease, with an exceptionally high burden. High-fat diet (HFD) is a popular diet behavior, whereas low-dose radiation (LDR) is an environmental physical factor. There is evidence to suggest that an HFD may exacerbate the onset of atherosclerosis. Whether the combination effect of HFD and LDR would have potential on atherosclerosis development remains incompletely unclear.

METHODS

In this study, ApoE-/- mice were used as atherosclerosis model animals to investigate the combination effects of HFD and LDR (10 × 0.01Gy, or 20 × 0.01Gy) on vascular lesions. Doppler ultrasound imaging, H&E staining, oil red O staining, western blotting, and immunohistochemistry (IHC) were used to assess the pro-atherosclerotic effects. LC-MS was used to detect the non-targeted lipidomic.

RESULTS

Long-term exposure of low-dose radiation at an accumulated dose of 0.2Gy significantly increased the occurrence of vascular stiffness and the aortic lesion in ApoE-/- mice. The synergistic effect of HFD and LDR was observed in the development of atherosclerosis, which might be linked to both the dysbiosis of lipid metabolism and the stimulation of the inflammatory signaling system. Moreover, LDR but not HFD can activate the cGAS-STING signaling through increasing the yield of cytosolic mitochondrial DNAs as well as the expression of cGAS protein. The activation of cGAS-STING signal triggers the release of IFN-α/-β, which functions as an inflammatory amplifier in the formation of atherosclerotic plaque.

CONCLUSION

The current study offers fresh insights into the risks and mechanism that underlie the development of atherosclerosis by LDR, and there is a combination effect of LDR and HFD with the involvement of cGAS-STING signal pathway.

Modelling radiobiology

Radiotherapy has played an essential role in cancer treatment for over a century, and remains one of the best-studied methods of cancer treatment. Because of its close links with the physical sciences, it has been the subject of extensive quantitative mathematical modelling, but a complete understanding of the mechanisms of radiotherapy has remained elusive. In part this is because of the complexity and range of scales involved in radiotherapy-from physical radiation interactions occurring over nanometres to evolution of patient responses over months and years. This review presents the current status and ongoing research in modelling radiotherapy responses across these scales, including basic physical mechanisms of DNA damage, the immediate biological responses this triggers, and genetic- and patient-level determinants of response. Finally, some of the major challenges in this field and potential avenues for future improvements are also discussed.

Radiation therapist education and the changing landscape in Africa

In the changing global landscape, education programs for radiation therapists (RTTs), also known as therapeutic radiographers or radiation therapy technologists, at higher education institutions (HEIs) are non-existent in many African countries. In countries with local RTT education programs, there is evidence of a wide variety of qualification types, including in-house training, diploma and degree offerings. However, what is consistent is the integrated curriculum approach to classroom theory and clinical work-based learning that across the continent follows the general structure of a work-integrated learning (WIL) approach, to enhance clinical competence and meet the needs of the health sector. This study used a qualitative approach with thematic analysis of publicly available documents and reflective writings followed by further analysis through application of the Cultural Historical Activity Theory (CHAT) to explore the changing landscape of oncology in Africa and the impact of this on the education of RTTs. The study was guided by the reflective research question: How can the systemic understanding of RTT training in a changing landscape enable competent and caring practice? The study extends prior research on RTT education in Africa and contributes to debates on the changing role of RTTs in a rapidly changing environment.

Immunoregulatory Engineering of Semiconducting Charge-Reversal Nanoantioxidant for Ameliorating Cancer Radioimmunotheranostics

Radiotherapy (RT) is a crucial clinical modality for cancer. However, nonselectivity, toxicity to normal tissues, and radio-resistance severely limit RT applications. This study develops a versatile X-ray theranostic nano-antioxidant (XTN) to prevent normal tissues from oxidative damage and induce systematic and robust anticancer immunity. XTN owns NIR-II photoacoustic (PA) imaging properties for precise discrimination of the tumor margin through, thereby improving the accuracy of RT. Additionally, XTN is a nano-antioxidant to enhance the cell viability of normal cells after irradiation. Most importantly, XTN scavenges reactive oxygen species (ROS) in the TME to preserve the stimulatory activity of released high mobility group protein B1 to dendritic cells (DCs) and recover T cells' immune function. Meanwhile, XTN achieves charge-reversal specifically releasing an immunomodulator (demethylcantharidin, DMC) in the acidic TME. Moreover, the specifically released DMC inhibits protein phosphatase-2A activity and reduces regulatory T cell (Treg) differentiation. In the bilateral 4T1 tumor model, XTN-mediated radioimmunotherapy remarkably boosts a systemic antitumor immune response and induces durable immunological memory against tumor growth.

Selenium-Doped Nanoheterojunctions for Highly Efficient Cancer Radiosensitization

Exploring efficient and low-toxicity radiosensitizers to break through the bottleneck of radiation tolerance, immunosuppression and poor prognosis remains one of the critical developmental challenges in radiotherapy. Nanoheterojunctions, due to their unique physicochemical properties, have demonstrated excellent radiosensitization effects in radiation energy deposition and in lifting tumor radiotherapy inhibition. Herein, they doped selenium (Se) into prussian blue (PB) to construct a nano-heterojunction (Se@PB), which could promote the increase of Fe2+/Fe3+ ratio and conversion of Se to a high valence state with Se introduction. The Fe2+-Se-Fe3+ electron transfer chain accelerates the rate of electron transfer on the surface of the nanoparticles, which in turn endows it with efficient X-ray energy transfer and electron transport capability, and enhances radiotherapy physical sensitivity. Furthermore, Se@PB induces glutathione (GSH) depletion and Fe2+ accumulation through pro-Fenton reaction, thereby disturbs the redox balance in tumor cells and enhances biochemical sensitivity of radiotherapy. As an excellent radiosensitizer, Se@PB effectively enhances X-ray induced mitochondrial dysfunction and DNA damage, thereby promotes cell apoptosis and synergistic cervical cancer radiotherapy. This study elucidates the radiosensitization mechanism of Se-doped nanoheterojunction from the perspective of the electron transfer chain and biochemistry reaction, which provides an efficient and low-toxic strategy in radiotherapy.

A retrospective study on the delay in three different timescales of CT simulation among patients with pediatric cancer in a tertiary hospital

Patients with pediatric cancer receive radiotherapy to cure several types of cancer, requiring computed tomography simulation (CT sim) for precise treatment. However, there is currently no suitable framework to reduce the inherent delays in CT sim. The present study aimed to identify the underlying causes of the delays in CT sim regarding three different time periods (duration of patient admission to CT sim, diagnosis to treatment and CT sim to treatment) among patients with pediatric cancer. A total of 58 patients with pediatric cancer who received radiation therapy under anesthesia at King Abdulaziz University Hospital (Jeddah, Saudi Arabia) between 2016 and 2021 (60 months) were included in the current study. The underlying cause of delays regarding three separate time periods was determined according to patient type, diagnosis, therapy type and year of diagnosis. The CT sim processing time averaged 73 days and was received by patients after 28.96±28.5 days. The major delays in terms of frequency and length of duration between different time points such as patient admission and CT sim, interval between diagnosis and treatment, and duration between CT sim and therapy were (mean±SD) 37.13±29.9, 58.08±24.9 and 28.15±7.9 days, respectively. Machine availability, instability of the patients' medical condition and intensity-modulated radiation therapy (IMRT) caused 66.6% of the delays. In conclusion, outpatients may experience CT sim delays. Machine availability, conditions of patients and IMRT treatment were the major reasons to cause the delay in CT sim. Strategies should be employed to prevent CT sim delays and improve patient experience.

Addressing challenges in low-income and middle-income countries through novel radiotherapy research opportunities

Although radiotherapy continues to evolve as a mainstay of the oncological armamentarium, research and innovation in radiotherapy in low-income and middle-income countries (LMICs) faces challenges. This third Series paper examines the current state of LMIC radiotherapy research and provides new data from a 2022 survey undertaken by the International Atomic Energy Agency and new data on funding. In the context of LMIC-related challenges and impediments, we explore several developments and advances-such as deep phenotyping, real-time targeting, and artificial intelligence-to flag specific opportunities with applicability and relevance for resource-constrained settings. Given the pressing nature of cancer in LMICs, we also highlight some best practices and address the broader need to develop the research workforce of the future. This Series paper thereby serves as a resource for radiation professionals.

Impact of electronic patient-reported outcome measures on patients' perception of the physician - the randomized ePREFERENCE study

BACKGROUND

Electronic Patient-reported outcome measures (ePROMs) are increasingly used in radiotherapy departments. However, the impact of ePROM integration on patients' perceptions of healthcare providers, particularly in terms of empathy and professionalism, remains unclear. Thus, this study aims to assess the patients' views on healthcare professionals during ePROM-based consultations.

METHODS

In this randomized trial, radiotherapy patients were enrolled and asked to evaluate video vignettes of consultations between a radiation oncologist and a patient. Two scenarios were shown in random order, one vignette portrayed a paper-chart-based clinic visit, and the other a consultation in which ePROMs were implemented. Established questionnaires such as Physician Compassion Questionnaire (PCQ), Jefferson Patient Perception of Physician Empathy (JPP), Physician Professionalism Questionnaire (PPQ) and Global Consultation Rating Scale (GCRS) were used to rate the healthcare professional. The primary endpoint was physician compassion.

RESULTS

Between May and August 2022, 152 patients, predominantly with malignancies of the breast, prostate, and brain participated. Patients rated the physician in ePROM-based consultations with higher mean scores for physician compassion compared to paper chart-based ones (36.4 vs. 34.2, p = 0.029). No negative impact of ePROMs was observed in terms of professionalism, global rating or physician empathy. Despite a shorter duration of the visit and reduced eye contact, 63 % of patients ultimately favored ePROM-based consultations.

CONCLUSION

The ePREFERENCE trial shows that the implementation of ePROMs in clinic visits during radiotherapy treatment positively impacts the patients' perception of the physician's compassion. ePROMs can therefore not only be considered a useful tool to improve workflows but are also broadly accepted by patients.

The Lancet Commission on prostate cancer: planning for the surge in cases

Prostate cancer is the most common cancer in men in 112 countries, and accounts for 15% of cancers. In this Commission, we report projections of prostate cancer cases in 2040 on the basis of data for demographic changes worldwide and rising life expectancy. Our findings suggest that the number of new cases annually will rise from 1·4 million in 2020 to 2·9 million by 2040. This surge in cases cannot be prevented by lifestyle changes or public health interventions alone, and governments need to prepare strategies to deal with it. We have projected trends in the incidence of prostate cancer and related mortality (assuming no changes in treatment) in the next 10–15 years, and make recommendations on how to deal with these issues.

For the Commission, we established four working groups, each of which examined a different aspect of prostate cancer: epidemiology and future projected trends in cases, the diagnostic pathway, treatment, and management of advanced disease, the main problem for most men diagnosed with prostate cancer worldwide. Throughout we have separated problems in high-income countries (HICs) from those in low-income and middle-income countries (LMICs), although we acknowledge that this distinction can be an oversimplification (some rich patients in LMICs can access high-quality care, whereas many patients in HICs, especially the USA, cannot because of inadequate insurance coverage). The burden of disease globally is already substantial, but options to improve care are already available at moderate cost. We found that late diagnosis is widespread worldwide, but especially in LMICs, where it is the norm. Early diagnosis improves prognosis and outcomes, and reduces societal and individual costs, and we recommend changes to the diagnostic pathway that can be immediately implemented. For men diagnosed with advanced disease, optimal use of available technologies, adjusted to the resource levels available, could produce improved outcomes. We also found that demographic changes (ie, changing age structures and increasing life expectancy) in LMICs will drive big increases in prostate cancer, and cases are also projected to rise in high-income countries. This projected rise in cases has driven the main thrust of our recommendations throughout. Dealing with this rise in cases will require urgent and radical interventions, particularly in LMICs, including an emphasis on education (both of health professionals and the general population) linked to outreach programmes to increase awareness. If implemented, these interventions would shift the case mix from advanced to earlier-stage disease, which in turn would necessitate different treatment approaches: earlier diagnosis would prompt a shift from palliative to curative therapies based around surgery and radiotherapy. Although age-adjusted mortality from prostate cancer is falling in HICs, it is rising in LMICs. And, despite large, well known differences in disease incidence and mortality by ethnicity (eg, incidence in men of African heritage is roughly double that in men of European heritage), most prostate cancer research has disproportionally focused on men of European heritage. Without urgent action, these trends will cause global deaths from prostate cancer to rise rapidly.

Current practices of craniospinal irradiation techniques in Turkey: a comprehensive dosimetric analysis

OBJECTIVE

This study evaluates various craniospinal irradiation (CSI) techniques used in Turkish centers to understand their advantages, disadvantages and overall effectiveness, with a focus on enhancing dose distribution.

METHODS

Anonymized CT scans of adult and pediatric patients, alongside target volumes and organ-at-risk (OAR) structures, were shared with 25 local radiotherapy centers. They were tasked to develop optimal treatment plans delivering 36 Gy in 20 fractions with 95% PTV coverage, while minimizing OAR exposure. The same CT data was sent to a US proton therapy center for comparison. Various planning systems and treatment techniques (3D conformal RT, IMRT, VMAT, tomotherapy) were utilized. Elekta Proknow software was used to analyze parameters, assess dose distributions, mean doses, conformity index (CI), and homogeneity index (HI) for both target volumes and OARs. Comparisons were made against proton therapy.

RESULTS

All techniques consistently achieved excellent PTV coverage (V95 > 98%) for both adult and pediatric patients. Tomotherapy closely approached ideal Dmean doses for all PTVs, while 3D-CRT had higher Dmean for PTV_brain. Tomotherapy excelled in CI and HI for PTVs. IMRT resulted in lower pediatric heart, kidney, parotid, and eye doses, while 3D-CRT achieved the lowest adult lung doses. Tomotherapy approached proton therapy doses for adult kidneys and thyroid, while IMRT excelled for adult heart, kidney, parotid, esophagus, and eyes.

CONCLUSION

Modern radiotherapy techniques offer improved target coverage and OAR protection. However, 3D techniques are continued to be used for CSI. Notably, proton therapy stands out as the most efficient approach, closely followed by Tomotherapy in terms of achieving superior target coverage and OAR protection.

Distance Traveled by Patients Globally to Access Radiation Therapy: A Systematic Review

PURPOSE

This study aimed to systematically review the literature on the travel patterns of patients seeking radiation therapy globally. It examined the distance patients travel for radiation therapy as well as secondary outcomes, including travel time.

METHODS AND MATERIALS

A comprehensive search of 4 databases was conducted from June 2022 to August 2022. Studies were included in the review if they were observational, retrospective, randomized/nonrandomized, published between June 2000 and June 2022, and if they reported on the global distance traveled for radiation therapy in the treatment of malignant or benign disease. Studies were excluded if they did not report travel distance or were not written in English.

RESULTS

Of the 168 studies, most were conducted in North America (76.3%), with 90.7% based in the United States. Radiation therapy studies for treating patients with breast cancer were the most common (26.6%), while external beam radiation therapy was the most prevalent treatment modality (16.6%). Forty-six studies reported the mean distance traveled for radiation therapy, with the shortest being 4.8 miles in the United States and the longest being 276.5 miles in Iran. It was observed that patients outside of the United States traveled greater distances than those living within the United States. Geographic location, urban versus rural residence, and patient population characteristics affected the distance patients traveled for radiation therapy.

CONCLUSIONS

This systematic review provides the most extensive summary to date of the travel patterns of patients seeking radiation therapy globally. The results suggest that various factors may contribute to the variability in travel distance patterns, including treatment center location, patient residence, and treatment modality. Overall, the study highlights the need for more research to explore these factors and to develop effective strategies for improving radiation therapy access and reducing travel burden.

Self-Shielding Gyroscopic Radiosurgery: A Prospective Experience and Analysis of the First 100 Patients

Background Stereotactic radiosurgery is a well-established treatment option for the management of various benign and malignant brain tumors. It can be delivered with several treatment platforms, usually requiring shielded radiation vaults to meet regulatory safety requirements. Recent technical advances have led to the first self-shielding platform enabling the delivery of gyroscopic radiosurgery (GRS). Given the limited number of GRS treatment platforms, the novelty of its characteristics, and the lack of available data, we report our prospective experience with the first 100 patients treated with GRS. Materials and methods Patients undergoing GRS for the treatment of intracranial tumors were enrolled in this prospective study. Patient and treatment characteristics, including patient satisfaction, were collected and analyzed. Results A total of 100 patients with 155 tumors were treated. The most commonly treated tumors comprised brain metastases (BM) (49%), vestibular schwannomas (31%), and meningiomas (14%). The median prescription dose for malignant and benign tumors was 20 and 13 Gy, respectively. The median prescription isodose line was 56%. Gross tumor volumes were small, with a median of 0.37 cc for BM and 0.92 cc for the other entities. The median total treatment time was 40 minutes. Dosimetric performance indices showed median values of 1.20 (conformity index), 1.24 (new conformity index), 1.74 (homogeneity index), and 3.13 (gradient index). Volumetric assessment of the treated tumors showed an overall decrease in size at the first available follow-up. Most patients were satisfied with the treatment experience. Conclusion Our first prospective experience of the use of GRS is favorable. Analyses of the dosimetric performance, treatment times, volumetric assessment, and patient satisfaction demonstrate its suitability for stereotactic treatments of intracranial tumors. Further prospective clinical and dosimetric analyses for GRS are pending.

Extending deterministic transport capabilities for very-high and ultra-high energy electron beams

Focused Very-High Energy Electron (VHEE, 50-300 MeV) and Ultra-High Energy Electron (UHEE, > 300 MeV) beams can accurately target both large and deeply seated human tumors with high sparing properties, while avoiding the spatial requirements and cost of proton and heavy ion facilities. Advanced testing phases are underway at the CLEAR facilities at CERN (Switzerland), NLCTA at Stanford (USA), and SPARC at INFN (Italy), aiming to accelerate the transition to clinical application. Currently, Monte Carlo (MC) transport is the sole paradigm supporting preclinical trials and imminent clinical deployment. In this paper, we propose an alternative: the first extension of the nuclear-reactor deterministic chain NJOY-DRAGON for VHEE and UHEE applications. We have extended the Boltzmann-Fokker-Planck (BFP) multigroup formalism and validated it using standard radio-oncology benchmarks, complex assemblies with a wide range of atomic numbers, and comprehensive irradiation of the entire periodic table. We report that [Formula: see text] of water voxels exhibit a BFP-MC deviation below [Formula: see text] for electron energies under [Formula: see text]. Additionally, we demonstrate that at least [Formula: see text] of voxels of bone, lung, adipose tissue, muscle, soft tissue, tumor, steel, and aluminum meet the same criterion between [Formula: see text] and [Formula: see text]. For water, the thorax, and the breast intra-operative benchmark, typical average BFP-MC deviations of [Formula: see text] and [Formula: see text] were observed at [Formula: see text] and [Formula: see text], respectively. By irradiating the entire periodic table, we observed similar performance between lithium ([Formula: see text]) and cerium ([Formula: see text]). Deficiencies observed between praseodymium ([Formula: see text]) and einsteinium ([Formula: see text]) have been reported, analyzed, and quantified, offering critical insights for the ongoing development of the Evaluated Nuclear Data File mode in NJOY.

Quality indicators for evaluating cancer care in low-income and middle-income country settings: a multinational modified Delphi study

This Policy Review sourced opinions from experts in cancer care across low-income and middle-income countries (LMICs) to build consensus around high-priority measures of care quality. A comprehensive list of quality indicators in medical, radiation, and surgical oncology was identified from systematic literature reviews. A modified Delphi study consisting of three 90-min workshops and two international electronic surveys integrating a global range of key clinical, policy, and research leaders was used to derive consensus on cancer quality indicators that would be both feasible to collect and were high priority for cancer care systems in LMICs. Workshop participants narrowed the list of 216 quality indicators from the literature review to 34 for inclusion in the subsequent surveys. Experts' responses to the surveys showed consensus around nine high-priority quality indicators for measuring the quality of hospital-based cancer care in LMICs. These quality indicators focus on important processes of care delivery from accurate diagnosis (eg, histologic diagnosis via biopsy and TNM staging) to adequate, timely, and appropriate treatment (eg, completion of radiotherapy and appropriate surgical intervention). The core indicators selected could be used to implement systems of feedback and quality improvement.

Non-coplanar lung SABR treatments delivered with a gantry-mounted x-ray tube

Objective.To create two non-coplanar, stereotactic ablative radiotherapy (SABR) lung patient treatment plans compliant with the radiation therapy oncology group (RTOG) 0813 dosimetric criteria using a simple, isocentric, therapy with kilovoltage arcs (SITKA) system designed to provide low cost external radiotherapy treatments for low- and middle-income countries (LMICs).Approach.A treatment machine design has been proposed featuring a 320 kVp x-ray tube mounted on a gantry. A deep learning cone-beam CT (CBCT) to synthetic CT (sCT) method was employed to remove the additional cost of planning CTs. A novel inverse treatment planning approach using GPU backprojection was used to create a highly non-coplanar treatment plan with circular beam shapes generated by an iris collimator. Treatments were planned and simulated using the TOPAS Monte Carlo (MC) code for two lung patients. Dose distributions were compared to 6 MV volumetric modulated arc therapy (VMAT) planned in Eclipse on the same cases for a Truebeam linac as well as obeying the RTOG 0813 protocols for lung SABR treatments with a prescribed dose of 50 Gy.Main results.The low-cost SITKA treatments were compliant with all RTOG 0813 dosimetric criteria. SITKA treatments showed, on average, a 6.7 and 4.9 Gy reduction of the maximum dose in soft tissue organs at risk (OARs) as compared to VMAT, for the two patients respectively. This was accompanied by a small increase in the mean dose of 0.17 and 0.30 Gy in soft tissue OARs.Significance.The proposed SITKA system offers a maximally low-cost, effective alternative to conventional radiotherapy systems for lung cancer patients, particularly in low-income countries. The system's non-coplanar, isocentric approach, coupled with the deep learning CBCT to sCT and GPU backprojection-based inverse treatment planning, offers lower maximum doses in OARs and comparable conformity to VMAT plans at a fraction of the cost of conventional radiotherapy.

Radiobiological Assessment of Targeted Radionuclide Therapy with [177Lu]Lu-PSMA-I&T in 2D vs. 3D Cell Culture Models

In vitro therapeutic efficacy studies are commonly conducted in cell monolayers. However, three-dimensional (3D) tumor spheroids are known to better represent in vivo tumors. This study used [177Lu]Lu-PSMA-I&T, an already clinically applied radiopharmaceutical for targeted radionuclide therapy against metastatic castrate-resistant prostate cancer, to demonstrate the differences in the radiobiological response between 2D and 3D cell culture models of the prostate cancer cell lines PC-3 (PSMA negative) and LNCaP (PSMA positive). After assessing the target expression in both models via Western Blot, cell viability, reproductive ability, and growth inhibition were assessed. To investigate the geometric effects on dosimetry for the 2D vs. 3D models, Monte Carlo simulations were performed. Our results showed that PSMA expression in LNCaP spheroids was highly preserved, and target specificity was shown in both models. In monolayers of LNCaP, no short-term (48 h after treatment), but only long-term (14 days after treatment) radiobiological effects were evident, showing decreased viability and reproductive ability with the increasing activity. Further, LNCaP spheroid growth was inhibited with the increasing activity. Overall, treatment efficacy was higher in LNCaP spheroids compared to monolayers, which can be explained by the difference in the resulting dose, among others.

One versus three weeks hypofractionated whole breast radiotherapy for early breast cancer treatment: the FAST-Forward phase III RCT

Background

FAST-Forward aimed to identify a 5-fraction schedule of adjuvant radiotherapy delivered in 1 week that was non-inferior in terms of local cancer control and as safe as the standard 15-fraction regimen after primary surgery for early breast cancer. Published acute toxicity and 5-year results are presented here with other aspects of the trial.

Design

Multicentre phase III non-inferiority trial. Patients with invasive carcinoma of the breast (pT1-3pN0-1M0) after breast conservation surgery or mastectomy randomised (1 : 1 : 1) to 40 Gy in 15 fractions (3 weeks), 27 Gy or 26 Gy in 5 fractions (1 week) whole breast/chest wall (Main Trial). Primary endpoint was ipsilateral breast tumour relapse; assuming 2% 5-year incidence for 40 Gy, non-inferiority pre-defined as < 1.6% excess for 5-fraction schedules (critical hazard ratio = 1.81). Normal tissue effects were assessed independently by clinicians, patients and photographs.

Sub-studies

Two acute skin toxicity sub-studies were undertaken to confirm safety of the test schedules. Primary endpoint was proportion of patients with grade ≥ 3 acute breast skin toxicity at any time from the start of radiotherapy to 4 weeks after completion. Nodal Sub-Study patients had breast/chest wall plus axillary radiotherapy testing the same three schedules, reduced to the 40 and 26 Gy groups on amendment, with the primary endpoint of 5-year patient-reported arm/hand swelling.

Limitations

A sequential hypofractionated or simultaneous integrated boost has not been studied.

Participants

Ninety-seven UK centres recruited 4096 patients (1361:40 Gy, 1367:27 Gy, 1368:26 Gy) into the Main Trial from November 2011 to June 2014. The Nodal Sub-Study recruited an additional 469 patients from 50 UK centres. One hundred and ninety and 162 Main Trial patients were included in the acute toxicity sub-studies.

Results

Acute toxicity sub-studies evaluable patients: (1) acute grade 3 Radiation Therapy Oncology Group toxicity reported in 40 Gy/15 fractions 6/44 (13.6%); 27 Gy/5 fractions 5/51 (9.8%); 26 Gy/5 fractions 3/52 (5.8%). (2) Grade 3 common toxicity criteria for adverse effects toxicity reported for one patient. At 71-month median follow-up in the Main Trial, 79 ipsilateral breast tumour relapse events (40 Gy: 31, 27 Gy: 27, 26 Gy: 21); hazard ratios (95% confidence interval) versus 40 Gy were 27 Gy: 0.86 (0.51 to 1.44), 26 Gy: 0.67 (0.38 to 1.16). With 2.1% (1.4 to 3.1) 5-year incidence ipsilateral breast tumour relapse after 40 Gy, estimated absolute differences versus 40 Gy (non-inferiority test) were -0.3% (-1.0-0.9) for 27 Gy (p = 0.0022) and -0.7% (-1.3-0.3) for 26 Gy (p = 0.00019). Five-year prevalence of any clinician-assessed moderate/marked breast normal tissue effects was 40 Gy: 98/986 (9.9%), 27 Gy: 155/1005 (15.4%), 26 Gy: 121/1020 (11.9%). Across all clinician assessments from 1 to 5 years, odds ratios versus 40 Gy were 1.55 (1.32 to 1.83; p < 0.0001) for 27 Gy and 1.12 (0.94-1.34; p = 0.20) for 26 Gy. Patient and photographic assessments showed higher normal tissue effects risk for 27 Gy versus 40 Gy but not for 26 Gy. Nodal Sub-Study reported no arm/hand swelling in 80% and 77% in 40 Gy and 26 Gy at baseline, and 73% and 76% at 24 months. The prevalence of moderate/marked arm/hand swelling at 24 months was 10% versus 7% for 40 Gy compared with 26 Gy.

Interpretation

Five-year local tumour incidence and normal tissue effects prevalence show 26 Gy in 5 fractions in 1 week is a safe and effective alternative to 40 Gy in 15 fractions for patients prescribed adjuvant local radiotherapy after primary surgery for early-stage breast cancer.

Future work

Ten-year Main Trial follow-up is essential. Inclusion in hypofractionation meta-analysis ongoing. A future hypofractionated boost trial is strongly supported.

Trial registration

FAST-Forward was sponsored by The Institute of Cancer Research and was registered as ISRCTN19906132.

Funding

This award was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme (NIHR award ref: 09/01/47) and is published in full in Health Technology Assessment; Vol. 27, No. 25. See the NIHR Funding and Awards website for further award information.

Patient selection for proton therapy using Normal Tissue Complication Probability with deep learning dose prediction for oropharyngeal cancer

BACKGROUND

In cancer care, determining the most beneficial treatment technique is a key decision affecting the patient's survival and quality of life. Patient selection for proton therapy (PT) over conventional radiotherapy (XT) currently entails comparing manually generated treatment plans, which requires time and expertise.

PURPOSE

We developed an automatic and fast tool, AI-PROTIPP (Artificial Intelligence Predictive Radiation Oncology Treatment Indication to Photons/Protons), that assesses quantitatively the benefits of each therapeutic option. Our method uses deep learning (DL) models to directly predict the dose distributions for a given patient for both XT and PT. By using models that estimate the Normal Tissue Complication Probability (NTCP), namely the likelihood of side effects to occur for a specific patient, AI-PROTIPP can propose a treatment selection quickly and automatically.

METHODS

A database of 60 patients presenting oropharyngeal cancer, obtained from the Cliniques Universitaires Saint Luc in Belgium, was used in this study. For every patient, a PT plan and an XT plan were generated. The dose distributions were used to train the two dose DL prediction models (one for each modality). The model is based on U-Net architecture, a type of convolutional neural network currently considered as the state of the art for dose prediction models. A NTCP protocol used in the Dutch model-based approach, including grades II and III xerostomia and grades II and III dysphagia, was later applied in order to perform automatic treatment selection for each patient. The networks were trained using a nested cross-validation approach with 11-folds. We set aside three patients in an outer set and each fold consists of 47 patients in training, five in validation and five for testing. This method allowed us to assess our method on 55 patients (five patients per test times the number of folds).

RESULTS

The treatment selection based on the DL-predicted doses reached an accuracy of 87.4% for the threshold parameters set by the Health Council of the Netherlands. The selected treatment is directly linked with these threshold parameters as they express the minimal gain brought by the PT treatment for a patient to be indicated to PT. To validate the performance of AI-PROTIPP in other conditions, we modulated these thresholds, and the accuracy was above 81% for all the considered cases. The difference in average cumulative NTCP per patient of predicted and clinical dose distributions is very similar (less than 1% difference).

CONCLUSIONS

AI-PROTIPP shows that using DL dose prediction in combination with NTCP models to select PT for patients is feasible and can help to save time by avoiding the generation of treatment plans only used for the comparison. Moreover, DL models are transferable, allowing, in the future, experience to be shared with centers that would not have PT planning expertise.

Radiotherapy resources in Latin America and the Caribbean: a review of current and projected needs based on International Atomic Energy Agency data

The inequitable access to radiotherapy globally is a complex undertaking that will require sustained work identifying gaps and mobilising efforts to resolve. The purpose of this review is to identify gaps and needs in radiotherapy in Latin America and the Caribbean. Data from 41 countries in Latin America and the Caribbean on teletherapy megavoltage units and brachytherapy resources were extracted from the International Atomic Energy Agency (IAEA) Directory of Radiotherapy Centers. These data were then matched to open-source data from GLOBOCAN and World Bank Data which included data on population size, gross national income per capita, cancer incidence, and mortality. These data were matched to current and projected cancer incidence and mortality (as estimated by the Global Cancer Observatory in 2020) to calculate current and projected gaps in external beam radiotherapy facilities. For brachytherapy, the analysis was focused on cervical cancer and included high dose rate and low dose rate machines. As of Oct 22, 2022, external beam radiotherapy was available in 32 (78%) of 41 countries, representing 742 radiotherapy centres and 1122 megavoltage units. Average coverage was 63%. LINACs accounted for 85% (955 of 1122) of megavoltage units and Cobalt-60 capacity decreased to 12% compared with in 2018. Median megavoltage units per 1000 cancer cases were 0·8 (IQR 0·54-1·03). Most countries clustered in the same range of gross national income per capita for teletherapy units per 1000 cases at a median of US$9380. The current deficit in megavoltage units is estimated at 668 units and is projected to be 2455 units by 2030. 28 (68%) of 41 countries had 279 installed brachytherapy services, both high dose rate and low dose rate, which could treat 108 420 patients with cervical cancer per year and meet the current needs, albeit with inequitable distribution of resources. Overall, this review indicated a 15% improvement in the current external beam radiotherapy capacity in Latin America and the Caribbean compared with 2018. However, there is still a current shortage of at least 668 extra units. By 2030, the need for megavoltage units will be double the current capacity. There is inequitable distribution of brachytherapy resources across the region primarily in the Caribbean. Adoption of hypofractionation can help overcome machine shortage; however, it will present technical challenges that need to be taken into account. Rays of Hope, is a novel IAEA initiative that is designed to mobilise global efforts to address radiotherapy gaps while ensuring the highest return on investment.

Hypofractionation: The standard for external beam breast irradiation

This overview provides the historical perspective of external beam breast hypofractionation over the last 50 years. It highlights the serious harm suffered by patients with breast cancer in the 1970's and 1980's because of new hypofractionation regimens based on a theoretical radiobiology model being adopted into clinical practice to solve a resource issue without testing within clinical trials and without the essential radiotherapy quality assurance. It then describes the high-quality clinical trials comparing 3-week with 5-week standard of care regimens that were initiated based on a strong scientific rationale for hypofractionation in breast cancer. Today, there are still challenges with universal implementation of the results of these moderate hypofractionation studies, but there is now a substantial body of evidence to support 3-week breast radiotherapy with several large randomised trials still to report. The limit of breast hypofractionation is then explored and randomised trials investigating 1-week radiotherapy are described. This approach is now standard of care in many countries for whole or partial breast radiotherapy and chest wall radiotherapy without immediate reconstruction. It also has the advantage of reducing burden of treatment for patients and providing cost-effective care. Further research is needed to establish the safety and efficacy of 1-week breast locoregional radiotherapy and following immediate breast reconstruction. In addition, clinical studies are required to determine how a tumour bed boost for patients with breast cancer at higher risk of relapse can be incorporated simultaneously into a 1-week radiotherapy schedule. As such, the breast hypofractionation story is still unfolding.

Radiation Oncology Research in Asia: Current Status and a Peep Into the Future From the Federation of Asian Organizations for Radiation Oncology

PURPOSE

This survey was conducted to assess the current research practices among the 14 members of the Federation of Asian Organizations for Radiation Oncology (FARO) committee, to inform measures for research capacity building in these nations.

MATERIALS AND METHODS

A 19-item electronic survey was sent to two research committee members from the 14 representative national radiation oncology organizations (N = 28) that are a part of FARO.

RESULTS

Thirteen of the 14 member organizations (93%) and 20 of 28 members (71.5%) responded to the questionnaire. Only 50% of the members stated that an active research environment existed in their country. Retrospective audits (80%) and observational studies (75%) were the most common type of research conducted in these centers. Lack of time (80%), lack of funding (75%), and limited training in research methodology (40%) were cited as the most common hindrances in conducting research. To promote research initiatives in the collaborative setting, 95% of the members agreed to the creation of site-specific groups, with head and neck (45%) and gynecological cancers (25%) being the most preferred disease sites. Projects focused on advanced external beam radiotherapy implementation (40%), and cost-effectiveness studies (35%) were cited as some of the potential areas for future collaboration. On the basis of the survey results, after result discussion and the FARO officers meeting, an action plan for the research committee has been created.

CONCLUSION

The results from the survey and the initial policy structure may allow facilitation of radiation oncology research in the collaborative setting. Centralization of research activities, funding support, and research-directed training are underway to help foster a successful research environment in the FARO region.

Exploring the Burden of Cancer in Pakistan: An Analysis of 2019 Data

Cancer has become a growing burden in Pakistan in recent times, posing a significant cause for concern. The World Health Organization has reported a steady increase in the incidence of cancer in Pakistan. According to the present study, breast cancer (24.1%), oral cavity (9.6%), colorectum (4.9%), esophagus (4.2%), and liver cancer (3.9%) were the five most prevalent cancers. Males were more likely to have oral cavity cancer (14.9%), colorectum cancer (6.8%), liver cancer (6.4%), prostate cancer (6.0%), and lung cancer (6.0%). In women (41.6%), breast (6.9%), oral cavity (5.5%), cervix (4.7%), and uterus cancer (4.1%) were the most common cancers. Middle-aged people (43.0%) were most likely to develop cancer, followed by seniors (30.0%) and adults (20.0%). Children and adolescents were most likely to develop cancers of the central nervous system (CNS), leukemia (18.7%), and Hodgkin (17.3%), followed by breast, oral cavity, colorectum, and prostate at other ages. Most patients were from Punjab (40.4%) and Sindh (32.2%). Approximately 30.0% of patients were diagnosed at stage III and stage IV. In terms of registered cases, breast cancer, oral cavity cancer, colon cancer, esophagus cancer, and liver cancer are among the highest. In the future, this information may prove useful for assessing the effectiveness of interventions.

Evolving practice in global healthcare: Remote physics support for low- and middle-income countries

The COVID-19 pandemic has disrupted traditional onsite support for radiotherapy clinics in low- and middle-income countries (LMIC). Clinics there have struggled to commission new techniques and receive onsite training for their staff. We sought to evaluate whether an offsite approach could fill this gap at a clinic in Jordan by requesting a clinical audit and attempting to commission volumetric modulated arc therapy (VMAT). Over 13 months, a consultant provided remote support for a radiotherapy center that had already obtained treatment equipment and licenses. The consultant began by conducting a virtual audit, using a remote login to the center's R&V and TPS, to identify any gaps in the clinical workflow. Suggestions for improving the clinical workflow were proposed, and change implementation was tracked through emails, social media apps, and video conferencing. An extensive table outlined the commissioning process, including all measurements to be done. Social media apps and shared documents were used to track measurements and analysis. The lack of person-to-person interaction in this new remote-support ecosystem created conflicts; we have highlighted some of these, as well as their resolution and the lessons learned from them. The virtual audit identified gaps categorized as machine QA, treatment plan review, and treatment delivery processes. Following the implementation of the proposals, motion management was added, and machine QA became more comprehensive. VMAT was commissioned using the reports of the AAPM and the IAEA. The main challenges for remote support were time difference, establishing an appropriate form and frequency of communication, tone of voice used in messages, and buy-in from local staff. This evolving practice will enable medical physicists to use modern, multimodal remote communication pathways to effectively transfer knowledge to centers in LMICs. The audit-proposal-improvement pathway for remote support can be incorporated to help others while avoiding the pitfalls we faced.

COMPUTED RADIOGRAPHY UTILIZATION FOR TELECOBALT60 TO ACHIEVE THE RADIATION CERTAINTY

OBJECTIVE

The aim: This research aimed to show the achievement of Telecobalt60 radiation certainty using computed radiography, in comparation with non-verified computed radiography.

PATIENTS AND METHODS

Materials and methods: This research is a quantitative study, randomized double-blind, and consecutive sampling design. The study was conducted by observing and com¬paring the data of verified computed radiography (VerC) computed radiograph for Telecobalt60 compared to the non-verified computed radiography (nVerC) Telecobalt60 data.

RESULTS

Results: The results showed that there are significant statistical differences in several measurement characteristics between the verified computed radiography arm and the non-verified computed radiography arm. All of the value divergences of the verified computed radiography arm are less than 7 mm while the non-verified computed radiography arm are 7 mm or more (P<0.050). Furthermore, all of the edge aspect of measurement in the verified computed radiography arms are less than the non-verified computed radiography, all without manual block utilization (P<0.050).

CONCLUSION

Conclusions: We conclude that Telecobalt60 radiation certainty is significantly better achieved by using computed radiography, when compared to non-verified computed radiography Telecobalt60 use. This research contributes to provide evidence based for better Telecobalt60 radiation accuracy and quality of radiotherapy outcome by using computed radiography.

Hypofractionation in Breast Cancer Radiotherapy Across World Bank Income Groups: Results of an International Survey

PURPOSE

Hypofractionated breast radiotherapy has been found to be equivalent to conventional fractionation in many clinical trials. Using data from the European Society for Radiotherapy and Oncology Global Impact of Radiotherapy in Oncology survey, we identified preferences for hypofractionation in breast cancer across World Bank income groups and the perceived facilitators and barriers to its use.

MATERIALS AND METHODS

An international, electronic survey was administered to radiation oncologists from 2018 to 2019. Demographics, practice characteristics, preferred hypofractionation regimen for specific breast cancer scenarios, and facilitators and barriers to hypofractionation were reported and stratified by World Bank income groups. Variables associated with hypofractionation were assessed using multivariate logistic regression models.

RESULTS

One thousand four hundred thirty-four physicians responded: 890 (62%) from high-income countries (HICs), 361 (25%) from upper-middle-income countries (UMICs), 183 (13%) from low- and lower-middle-income countries (LLMICs). Hypofractionation was preferred most frequently in node-negative disease after breast-conserving surgery, with the strongest preference reported in HICs (78% from HICs, 54% from UMICs, and 51% from LLMICs, P < .001). Hypofractionation for node-positive disease postmastectomy was more frequently preferred in LLMICs (28% from HICs, 15% from UMICs, and 35% from LLMICs, P < .001). Curative doses of 2.1 to < 2.5 Gy in 15-16 fractions were most frequently reported, with limited preference for ultra-hypofractionation, but significant variability in palliative dosing. In adjusted analyses, UMICs were significantly less likely than LLMICs to prefer hypofractionation across all curative clinical scenarios, whereas respondents with > 1 million population catchments and with intensity-modulated radiotherapy were more likely to prefer hypofractionation. The most frequently cited facilitators and barriers were published evidence and fear of late toxicity, respectively.

CONCLUSION

Preference for hypofractionation varied for curative indications, with greater acceptance in earlier-stage disease in HICs and in later-stage disease in LLMICs. Targeted educational interventions and greater inclusivity in radiation oncology clinical trials may support greater uptake.

Preclinical safety assessment of photoluminescent metal quantum clusters stabilized with autologous serum proteins for host specific theranostics

Host derived serum proteome stabilised red-emitting gold quantum clusters (or Au-QC-NanoSera or QCNS) of size range ~2 nm have been synthesised in a first reported study. The host serum was taken from bovine, murine and human origins to establish the proof of concept. In-vitro biocompatibility with normal murine L929 fibroblast cells and radiosensitisation ability against PLC/PRF/5 hepatoma cells was established. A concentration dependant radiosensitisation effect of QCNS at differential γ-radiation doses was observed with almost 90% killing of cancer cells at a radiation dose of 5Gy. Acute and subacute safety, and non-immunogenicity of autologously derived QCNS was established in in-bred C57BL/6 mice. The biodistribution analysis revealed that the QCNS were effectively cleared from the body over a course of 28 days and were found to pose no major threat to the proper functioning and morphology of the mice.