Estimating the demand for radiotherapy from the evidence: A review of changes from 2003 to 2012

Radiotherapy on-chip: microfluidics for translational radiation oncology

The clinical importance of radiotherapy in the treatment of cancer patients justifies the development and use of research tools at the fundamental, pre-clinical, and ultimately clinical levels, to investigate their toxicities and synergies with systemic agents on relevant biological samples. Although microfluidics has prompted a paradigm shift in drug discovery in the past two decades, it appears to have yet to translate to radiotherapy research. However, the materials, dimensions, design versatility and multiplexing capabilities of microfluidic devices make them well-suited to a variety of studies involving radiation physics, radiobiology and radiotherapy. This review will present the state-of-the-art applications of microfluidics in these fields and specifically highlight the perspectives offered by radiotherapy on-a-chip in the field of translational radiobiology and precision medicine. This body of knowledge can serve both the microfluidics and radiotherapy communities by identifying potential collaboration avenues to improve patient care.

An Integrated Approach Reveals DNA Damage and Proteotoxic Stress as Main Effects of Proton Radiation in S. cerevisiae

Proton radiotherapy (PRT) has the potential to reduce the normal tissue toxicity associated with conventional photon-based radiotherapy (X-ray therapy, XRT) because the active dose can be more directly targeted to a tumor. Although this dosimetric advantage of PRT is well known, the molecular mechanisms affected by PRT remain largely elusive. Here, we combined the molecular toolbox of the eukaryotic model Saccharomyces cerevisiae with a systems biology approach to investigate the physiological effects of PRT compared to XRT. Our data show that the DNA damage response and protein stress response are the major molecular mechanisms activated after both PRT and XRT. However, RNA-Seq revealed that PRT treatment evoked a stronger activation of genes involved in the response to proteotoxic stress, highlighting the molecular differences between PRT and XRT. Moreover, inhibition of the proteasome resulted in decreased survival in combination with PRT compared to XRT, not only further confirming that protons induced a stronger proteotoxic stress response, but also hinting at the potential of using proteasome inhibitors in combination with proton radiotherapy in clinical settings.

Advanced practice roles of therapeutic radiographers/radiation therapists: A systematic literature review

INTRODUCTION

Advances in Radiotherapy (RT) technology and increase of complexity in cancer care have enabled the implementation of new treatment techniques. Subsequently, a greater level of autonomy, responsibility, and accountability in the practice of Therapeutic Radiographers/Radiation Therapists (TR/RTTs) has led to Advanced Practice (AP) roles. The published evidence of this role is scattered with confusing terminology and divergence regarding the perception of whether a specific role represents AP internationally. This study aims to establish an international baseline of evidence on AP roles in RT to identify roles and activities performed by TR/RTTs at advanced level practice and to summarise the impact.

METHODS

A systematic PRISMA review of the literature was undertaken. Thematic analysis was used to synthesise the roles and associated activities. Six RT external experts validated the list. The impact was scrutinised in terms of clinical, organisational, and professional outcomes.

RESULTS

Studies (n = 87) were included and categorised into four groups. AP roles were listed by clinical area, site-specific, and scope of practice, and advanced activities were organised into seven dimensions and 27 sub-dimensions. Three most-reported outcomes were: enhanced service capacity, higher patient satisfaction, and safety maintenance.

CONCLUSION

Evidence-based AP amongst TR/RTTs show how AP roles were conceptualised, implemented, and evaluated. Congruence studies have shown that TR/RTTs are at par with the gold-standard across the various AP roles.

IMPLICATIONS FOR PRACTICE

This is the first systematic literature review synthetisising AP roles and activities of TR/RTTs. This study also identified the main areas of AP that can be used to develop professional frameworks and education guiding policy by professional bodies, educators and other stakeholders.

Dose Rate Effects on the Selective Radiosensitization of Prostate Cells by GRPR-Targeted Gold Nanoparticles

For a while, gold nanoparticles (AuNPs) have been recognized as potential radiosensitizers in cancer radiation therapy, mainly due to their physical properties, making them appealing for medical applications. Nevertheless, the performance of AuNPs as radiosensitizers still raises important questions that need further investigation. Searching for selective prostate (PCa) radiosensitizing agents, we studied the radiosensitization capability of the target-specific AuNP-BBN in cancer versus non-cancerous prostate cells, including the evaluation of dose rate effects in comparison with non-targeted counterparts (AuNP-TDOTA). PCa cells were found to exhibit increased AuNP uptake when compared to non-tumoral ones, leading to a significant loss of cellular proliferation ability and complex DNA damage, evidenced by the occurrence of multiple micronucleus per binucleated cell, in the case of PC3 cells irradiated with 2 Gy of γ-rays, after incubation with AuNP-BBN. Remarkably, the treatment of the PC3 cells with AuNP-BBN led to a much stronger influence of the dose rate on the cellular survival upon γ-photon irradiation, as well as on their genomic instability. Overall, AuNP-BBN emerged in this study as a very promising nanotool for the efficient and selective radiosensitization of human prostate cancer PC3 cells, therefore deserving further preclinical evaluation in adequate animal models for prostate cancer radiotherapy.

Complex housing partially mitigates low dose radiation-induced changes in brain and behavior in rats

Purpose: In recent years, much effort has been focused on developing new strategies for the prevention and mitigation of adverse radiation effects on healthy tissues and organs, including the brain. The brain is very sensitive to radiation effects, albeit as it is highly plastic. Hence, deleterious radiation effects may be potentially reversible. Because radiation exposure affects dendritic space, reduces the brain’s ability to produce new neurons, and alters behavior, mitigation efforts should focus on restoring these parameters. To that effect, environmental enrichment through complex housing (CH) and exercise may provide a plausible avenue for exploration of protection from brain irradiation. CH is a much broader concept than exercise alone, and constitutes exposure of animals to positive physical and social stimulation that is superior to their routine housing and care conditions. We hypothesized that CHs may lessen harmful neuroanatomical and behavioural effects of low dose radiation exposure. Methods: We analyzed and compared cerebral morphology in animals exposed to low dose head, bystander (liver), and scatter irradiation on rats housed in either the environmental enrichment condos or standard housing. Results: Enriched condo conditions ameliorated radiation-induced neuroanatomical changes. Moreover, irradiated animals that were kept in enriched CH condos displayed fewer radiation-induced behavioural deficits than those housed in standard conditions. Conclusions: Animal model-based environmental enrichment strategies, such as CH, are excellent surrogate models for occupational and exercise therapy in humans, and consequently have significant translational possibility. Our study may thus serve as a roadmap for the development of new, easy, safe and cost-effective methods to prevent and mitigate low-dose radiation effects on the brain.

Disparities in radiation therapy utilization for cancer patients in Victoria

Introduction

To evaluate the proportion of cancer patients who received radiation therapy (RT) within 12 months of cancer diagnosis (RTU12) and identify factors associated with RTU12.

Methods

This is a population‐based cohort of individuals with incident cancer, diagnosed between 2013 and 2017 in Victoria. Data linkages were performed between the Victorian Cancer Registry and Victorian Radiotherapy Minimum Dataset. The primary outcome was the proportion of patients who had RTU12. For the three most common cancers (i.e., prostate, breast and lung cancer), the time trend in RTU12 and factors associated with RTU12 were evaluated.

Results

The overall RTU12 in our study cohort was 26–20% radical RT and 6% palliative RT. Of the 21,735 men with prostate cancer, RTU12 was 17%, with no significant change over time (P‐trend = 0.53). In multivariate analyses, increasing age and lower socioeconomic status were independently associated with higher RTU12 for prostate cancer. Of the 20,883 women with breast cancer, RTU12 was 64%, which increased from 62% in 2013 to 65% in 2017 (P‐trend < 0.05). In multivariate analyses, age, socioeconomic status and area of residency were independently associated with RTU12 for breast cancer. Of the 13,093 patients with lung cancer, RTU12 was 42%, with no significant change over time (P‐trend = 0.16). In multivariate analyses, younger age, male and lower socioeconomic status were independently associated with higher RTU12.

Conclusion

In this large population‐based state‐wide cohort of cancer patients, only 1 in 4 had RT within 12 months of diagnosis. There were marked sociodemographic disparities in RTU12 for prostate, breast and lung cancer patients.

The changing radiation oncology landscape in New Zealand

INTRODUCTION

This paper outlines the New Zealand (NZ) responses to the biennial facilities surveys of the Royal Australian and New Zealand College of Radiation Oncologists (RANZCR), Faculty of Radiation Oncology (FRO) from 2011 to 2019.

METHODS

The facilities survey is conducted by the FRO Economics and Workforce Committee (FROEWC) and focuses on equipment, treatment activities and staffing.

RESULTS

The number of facilities increased by two to 10, both in the private sector. The total number of linear accelerators (linacs) increased by four; one in public and three in private. The majority of linacs were over 8 years old (62.5%). Treatment courses have increased by 19% and fraction numbers by 13.7%. Courses per linac have remained relatively constant. There was growth in IMRT, orthovoltage, high dose rate brachytherapy and paediatric treatments. There was a slow increase in number of radiation oncologists and trainees. The number of radiation therapists was unchanged with a 20% increase in treatment courses per radiation therapist. Physicist numbers have increased but 61.4% of physicists are overseas-trained and vacancies persist.

CONCLUSION

The survey results indicate a rapidly changing radiation oncology landscape in NZ between 2011 and 2019. The challenges of increases in cancer numbers, treatment courses and complexity of treatments and a need to focus on quality standards against a set of minimal increase in machine numbers, ageing machines, static or slowly increasing staffing numbers and heavy reliance on overseas staffing require a national review of radiation oncology services to ensure a sustainable future.

National reference levels of CT procedures dedicated for treatment planning in radiation oncology

OBJECTIVE

To present results of the first national survey on reference levels of CT imaging performed for the treatment planning purposes in radiation oncology in Croatia.

METHODS

Data for CT protocols of five anatomical regions including head, head and neck, pelvis, breast, and thorax were collected at eight radiation oncology departments in Croatia. Data included volume CT dose index (CTDI_vol), dose-length product (DLP), scan length and set of acquisition and reconstruction parameters. Data on a total of 600 patients were collected. Median values of scan length, DLP and CTDI_vol were calculated for each acquisition protocol. Third quartiles of the median CTDI_vol and DLP values were proposed as the national radiotherapy planning reference levels (RPRL).

RESULTS

The largest CoV were assessed for RT Breast (63.8% for CTDI_vol), RT Thorax (79.7% for DLP) and RT H&N (21.2% for scan length). RT Head had the lowest CoV for CTDI_vol (1,9%) and DLP (17,2%), while RT Breast had the lowest coefficient of variation for scan length (12.8%). Proposed national RPRLs are: for RT Head CTDI_vol16cm = 62 mGy and DLP_16cm = 1738 mGy.cm; for RT H&N CTDI_vol16cm = 35 mGy and DLP_16cm = 1444 mGy.cm; for RT Breast CTDI_vol32cm = 16 mGy and DLP_32cm = 731 mGy.cm; for RT Thorax CTDI_vol32cm = 17 mGy and DLP_32cm = 865 mGy.cm; for RT Pelvis CTDI_vol32cm = 20 mGy and DLP_32cm = 1133 mGy.cm.

CONCLUSIONS

Results of this study show variations in CT imaging for treatment planning practice at the national level which call for optimization of procedures.

CAR-T Plus Radiotherapy: A Promising Combination for Immunosuppressive Tumors

Radiotherapy (RT) is the standard-of-care treatment for more than half of cancer patients with localized tumors and is also used as palliative care to facilitate symptom relief in metastatic cancers. In addition, RT can alter the immunosuppressive tumor microenvironment (TME) of solid tumors to augment the anti-tumor immune response of immune checkpoint blockade (ICB). The rationale of this combination therapy can also be extended to other forms of immunotherapy, such as chimeric antigen receptor T cell (CAR-T) therapy. Similar to ICB, the efficacy of CAR-T therapy is also significantly impacted by the immunosuppressive TME, leading to compromised T cell function and/or insufficient T cell infiltration. In this review, we will discuss some of the key barriers to the activity of CAR-T cells in the immunosuppressive TME and focus on how RT can be used to eliminate or bypass these barriers. We will present the challenges to achieving success with this therapeutic partnership. Looking forward, we will also provide strategies currently being investigated to ensure the success of this combination strategy in the clinic.

Incident review in radiation oncology

By its very nature, radiation oncology is a complex, multi-profession dynamic modality of cancer treatment. There are multiple steps with many handovers of work and many opportunities for patient safety to be compromised. Patient safety events can manifest as either actual incidents or near miss/close call events. Reporting and learning from these events is key to quality improvement and patient safety. In this paper, we aim to provide an overview of radiation oncology incident reporting and learning systems. We review the importance of the use of a standardized taxonomy and classification that is specific to radiation oncology workflow, the international systems in current use and the current reporting requirements in Australia and New Zealand. Equally important is the culture that exists alongside the incident learning system. A just culture, where support for reporting exists and there is an adaptive responsive environment to learn and improve patient safety. The incident learning and patient safety system requires constant effort to make it a success. We describe potential measures of safety culture and of relative patient safety and recommend their routine use. We offer this review to stimulate the effort towards a binational voluntary incident learning system, a key pillar for the improvement in patient safety in radiation oncology.

Availability of technology for managing cancer patients in the Southeast European (SEE) region

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Gap of public on-the-ground cancer data was addressed through questionnaires to professionals in the SEE region.

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There is a lack of diagnostic imaging and radiotherapy modalities in the SEE region in comparison to Western Europe.

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The Mortality to incidence ratio correlates inversely with the economic development and the availability of radiotherapy equipment.

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The cancer incidence in SEE countries was correlate directly with the life expectancy and the availability of diagnostic equipment.

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The need for reliable national and regional cancer registries in SEE countries for data collection and analysis has been emphasized.

Background

The Southeast European (SEE) region of 10 countries and about 43 million people differs from Western Europe in that most SEE countries lack active cancer registries and have fewer diagnostic imaging devices and radiotherapy (RT) units. The main objective of this research is to initiate a common platform for gathering SEE regional cancer data from the ground up to help these countries develop common cancer management strategies.

Methods

To obtain detailed on-the-ground information, we developed separate questionnaires for two SEE groups: a) ONCO - oncologists regarding cancer treatment modalities and the availability of diagnostic imaging and radiotherapy equipment; and b) REG - national radiation protection and safety regulatory bodies regarding diagnostic imaging and radiotherapy equipment in SEE facilities.

Results

Based on responses from 13/17 ONCO participants (at least one from each country) and from 9/10 REG participants (all countries but Albania), cancer incidence rates are higher in those SEE countries that have greater access to diagnostic imaging equipment while cancer mortality-to-incidence (MIR) ratios are higher in countries that lack radiotherapy equipment.

Conclusion

By combining unique SEE region information with data available from major global databases, we demonstrated that the availability of diagnostic imaging and radiotherapy equipment in the SEE countries is related to their economic development. While immediate diagnostic imaging and radiation therapy capacity building is necessary, it is also essential to develop both national and SEE-regional cancer registries in order to understand the heterogeneity of each country’s needs and to establish regional collaborative strategies for combating cancer.

Nanotechnology Driven Cancer Chemoradiation: Exploiting the Full Potential of Radiotherapy with a Unique Combination of Gold Nanoparticles and Bleomycin

One of the major issues in current radiotherapy (RT) is the associated normal tissue toxicity. Enhancement of the RT effect with novel radiosensitizers can address this need. In this study, gold nanoparticles (GNPs) and bleomycin (BLM) were used as a unique combination of radiosensitizers. GNPs offer a two-fold promise as a delivery vehicle for BLM and as a radiosensitizing agent. In this study, GNPs were functionalized and complexed with BLM using a gold-thiol bond (denoted GNP-BLM). Our results show that there was a 40% and 10% decrease in cell growth with GNP-BLM vs. free BLM for the MIA PaCa-2 and PC-3 cell lines, respectively. Testing the GNP-BLM platform with RT showed an 84% and 13% reduction in cell growth in MIA PaCa-2 cells treated with GNP-BLM and GNPs, respectively. Similar results were seen with PC-3 cells. The efficacy of this approach was verified by mapping DNA double-strand breaks (DSBs) as well. Therefore, this proposed incorporation of nanomedicine with RT is promising in achieving a significantly higher therapeutic ratio which is necessary to make a paradigm change to the current clinical approach.

Radiation Oncology Residency Training in Latin America, a Call to Attention

Purpose

Despite the call to increase the number of radiation oncologists in Latin America, the quality, similarity, and number of residency training programs are unknown. We seek to describe the current state of residency programs in radiation oncology in Latin America.

Methods and Materials

Latin American Residents in Radiation Oncology performed a cross-sectional analysis of universities and training centers for radiation oncologists in Latin America. Latin American Residents in Radiation Oncology members identified and contacted current residents and specialists at each center to obtain information and documents that described their training curricula.

Results

As of 2020, 13 of 23 (56.5%) Latin American countries have radiation oncology training. Seventy-three training centers were identified (59 active and 14 inactive), associated with 28 universities. On average, each active center trains 2.6 new residents per year, and in total, 156 residents are trained annually. The average length of training programs is 3.6 years. Brazil and Mexico comprise 31 (52.5%) and 7 (11.9%) of active programs, respectively, and 64 (41.8%) and 50 (32.7%) residents, respectively. Training is available in 38 cities in 13 countries, and outside Brazil and Mexico, only 13 cities in 11 countries (9 capitals and 4 noncapital cities). Individualized curriculum documents were provided by 20 (83.3%) of 24 non-Brazilian programs, while 1 standardized guideline was provided for Brazilian training programs. These demonstrated variation between subjects taught, their devoted time, outside specialty rotations, and experiences in modern techniques. Seventy-five percent include volumetric modulated arc therapy, 70% stereotactic radiosurgery, and 55% stereotactic body radiation therapy training. One-hundred percent include gynecologic brachytherapy education and <50% brachytherapy education in other disease sites.

Conclusions

Training is highly centralized in capital cities. The number of trainees is insufficient to close the current human resource divide but is limited by available job openings. Over 50% of training programs now include technological training in stereotactic radiosurgery, stereotactic body radiation therapy, or volumetric modulated arc therapy; however, substantial variation still exists. The development of radiation oncology specialists must be improved and modernized to address the escalating demand for cancer care.

Prospective Randomized Phase II Study of Stereotactic Body Radiotherapy (SBRT) vs. Conventional Fractionated Radiotherapy (CFRT) for Chinese Patients with Early-Stage Localized Prostate Cancer

Background: Stereotactic body radiotherapy (SBRT) has potential radiobiologic and economic advantages over conventional fractionated radiotherapy (CFRT) in localized prostate cancer (PC). This study aimed to compare the effects of these two distinct fractionations on patient-reported quality of life (PRQOL) and tolerability. Methods: In this prospective phase II study, patients with low- and intermediate-risk localized PC were randomly assigned in a 1:1 ratio to the SBRT (36.25 Gy/5 fractions/2 weeks) or CFRT (76 Gy/38 fractions/7.5 weeks) treatment groups. The primary endpoint of variation in PRQOL at 1 year was assessed by changes in the Expanded Prostate Cancer Index Composite (EPIC) questionnaire scores and analysed by z-tests and t-tests. Results: Sixty-four eligible Chinese men were treated (SBRT, n = 31; CFRT, n = 33) with a median follow-up of 2.3 years. At 1 year, 40.0%/46.9% of SBRT/CFRT patients had a >5-point decrease in bowel score (p = 0.08/0.28), respectively, and 53.3%/46.9% had a >2-point decrease in urinary score (p = 0.21/0.07). There were no significant differences in EPIC score changes between the arms at 3, 6, 9 and 12 months, but SBRT was associated with significantly fewer grade ≥ 1 acute and 1-year late gastrointestinal toxicities (acute: 35% vs. 87%, p < 0.0001; 1-year late: 64% vs. 84%, p = 0.03), and grade ≥ 2 acute genitourinary toxicities (3% vs. 24%, p = 0.04) compared with CFRT. Conclusion: SBRT offered similar PRQOL and less toxicity compared with CFRT in Chinese men with localized PC.

Intra- and inter-fraction relative range verification in heavy-ion therapy using filtered interaction vertex imaging

Heavy-ion therapy, particularly using scanned (active) beam delivery, provides a precise and highly conformal dose distribution, with maximum dose deposition for each pencil beam at its endpoint (Bragg peak), and low entrance and exit dose. To take full advantage of this precision, robust range verification methods are required; these methods ensure that the Bragg peak is positioned correctly in the patient and the dose is delivered as prescribed. Relative range verification allows intra-fraction monitoring of Bragg peak spacing to ensure full coverage with each fraction, as well as inter-fraction monitoring to ensure all fractions are delivered consistently. To validate the proposed filtered interaction vertex imaging (IVI) method for relative range verification, a¹⁶O beam was used to deliver 12 Bragg peak positions in a 40 mm poly-(methyl methacrylate) phantom. Secondary particles produced in the phantom were monitored using position-sensitive silicon detectors. Events recorded on these detectors, along with a measurement of the treatment beam axis, were used to reconstruct the sites of origin of these secondary particles in the phantom. The distal edge of the depth distribution of these reconstructed points was determined with logistic fits, and the translation in depth required to minimize theχ²statistic between these fits was used to compute the range shift between any two Bragg peak positions. In all cases, the range shift was determined with sub-millimeter precision, to a standard deviation of the mean of 220(10)μm. This result validates filtered IVI as a reliable relative range verification method, which should be capable of monitoring each energy step in each fraction of a scanned heavy-ion treatment plan.

Levels of Evidence for Radiation Therapy Recommendations in the National Comprehensive Cancer Network (NCCN) Clinical Guidelines

Purpose

The National Comprehensive Cancer Network (NCCN) clinical guidelines influence medical practice, payor coverage, and standards of care. The levels of evidence underlying radiation therapy recommendations in NCCN have not been systematically explored. Herein, we aim to systematically investigate the NCCN recommendations pertaining to the categories of consensus and evidence (CE) for radiation therapy.

Methods and Materials

We evaluated the distribution of CE underlying current treatment recommendations for the 20 most prevalent cancers in the United States with at least 10 radiation therapy recommendations in the NCCN clinical guidelines. For context, the distribution of evidence in the radiation therapy guidelines was compared with that of systemic therapy using a χ² test. The proportion of category I CE between radiation and systemic therapy was compared using a 2-proportion, 2-tailed z-test in total and for each disease site. A P value of < .05 was considered significant.

Results

Among all radiation therapy recommendations, the proportions of category I, IIA, IIB, and III CE were 9.7%, 80.6%, 8.4%, and 1.3%, respectively. When analyzed by disease site, cervix and breast cancer had the highest portion of category I CE (33% and 31%, respectively). There was no radiation therapy category I CE for hepatobiliary, bone, pancreatic, melanoma, and uterine cancers. There was a significant difference in the distribution of CE between the systemic therapy recommendations and the radiation therapy recommendations (χ² statistic 64.16, P < .001). Overall, there was a significantly higher proportion of category I CE in the systemic therapy recommendations compared with the radiation therapy recommendations (12.3% vs 9.7%, P = .043).

Conclusions

Only 9.7% of radiation therapy recommendations in NCCN guidelines are category I CE. The highest levels of evidence for radiation therapy are in breast and cervical cancers. Despite major advances in the field, these data underline that the majority of NCCN radiation therapy recommendations are based on uniform expert opinion and not on higher level evidence.

Quantification of radiation-induced DNA double strand break repair foci to evaluate and predict biological responses to ionizing radiation

Radiation-induced foci (RIF) are nuclear puncta visualized by immunostaining of proteins that regulate DNA double-strand break (DSB) repair after exposure to ionizing radiation. RIF are a standard metric for measuring DSB formation and repair in clinical, environmental and space radiobiology. The time course and dose dependence of their formation has great potential to predict in vivo responses to ionizing radiation, predisposition to cancer and probability of adverse reactions to radiotherapy. However, increasing complexity of experimentally and therapeutically setups (charged particle, FLASH …) is associated with several confounding factors that must be taken into account when interpreting RIF values. In this review, we discuss the spatiotemporal characteristics of RIF development after irradiation, addressing the common confounding factors, including cell proliferation and foci merging. We also describe the relevant endpoints and mathematical models that enable accurate biological interpretation of RIF formation and resolution. Finally, we discuss the use of RIF as a biomarker for quantification and prediction of in vivo radiation responses, including important caveats relating to the choice of the biological endpoint and the detection method. This review intends to help scientific community design radiobiology experiments using RIF as a key metric and to provide suggestions for their biological interpretation.

In-vitro 3D modelling for charged particle therapy - Uncertainties and opportunities

Radiation therapy is a critical component of oncologic management, with more than half of all cancer patients requiring radiotherapy at some point during their disease course. Over the last decade, there has been increasing interest in charged particle therapy due to its advantageous physical and radiobiologic properties, with the therapeutic use of proton beam therapy (PBT) expanding worldwide. However, there remain large gaps in our knowledge of the radiobiologic mechanisms that underlie key aspects of PBT, such as variations in relative biologic effectiveness (RBE), radioresistance, DNA damage response and repair pathways, as well as immunologic effects. In addition, while the emerging technique of ultra-high dose rate or FLASH radiotherapy, with its potential to further reduce normal tissue toxicities, is an exciting development, in-depth study is needed into the postulated biochemical mechanisms that underpin the FLASH effect such as the oxygen depletion hypothesis as well as the relative contributions of immune responses and the tumor microenvironment. Further investigation is also required to ensure that the FLASH effect is not diminished or lost in PBT. Current methods to evaluate the biologic effects of charged particle therapy rely heavily on 2D cell culture systems and/or animal models. However, both of these methods have well-recognized limitations which limit translatability of findings from bench to bedside. The advent of novel three-dimensional in-vitro tumor models offers a more physiologically relevant and high throughput in-vitro system for the study of tumor development as well as novel therapeutic approaches such as PBT. Advances in 3D cell culture methods, together with knowledge of disease mechanism, biomarkers, and genomic data, can be used to design personalized 3D models that most closely recapitulate tumor microenvironmental factors promoting a particular disease phenotype, moving 3D models and PBT into the age of precision medicine.

Surgical and radiotherapy patterns of care in the management of breast cancer in NSW and ACT Australia

INTRODUCTION

This study aims to report on the surgical and radiotherapy patterns of breast cancer care in New South Wales (NSW) and Australian Capital Territory (ACT) in Australia, to identify factors that impact on utilisation of evidence-based treatment and to report on the overall survival (OS) rate and the influencing factors on OS.

METHODS

Cancer registry data linked to hospital records for all patients with breast cancer diagnosis in NSW and ACT between 2009 and 2014 were used to calculate rates of breast conserving surgery (BCS), mastectomy, sentinel lymph node biopsy (SLNB), axillary lymph node dissection (ALND) and radiotherapy. Multivariate analysis used to identify factors that led to variations in care. 5-year OS was calculated and cox regression model assessed factors that influenced survival.

RESULTS

Data for 30,337 patients were analysed. BCS and mastectomy rates were 64% and 36%, respectively. The SLNB, ALND and ALND after SLNB rates were 61.5%, 32.1% and 6.4%, respectively. Radiotherapy was utilised in 63%. Younger age, socio-economic disadvantage, longer distance to a radiotherapy facility and overseas place of birth were factors that predicted for increased rates of mastectomy and ALND. Radiotherapy was more likely to be utilised in later years of diagnosis, patients between 40-69 years old, and those who lived in major cities and closer to a radiotherapy facility. 5-year OS was 80.5%. Older patients, the socioeconomically disadvantaged and those advanced tumours had worse survival.

CONCLUSION

Variations in breast cancer care continue to exist in certain patient groups that we identified. Targeted strategic planning and further research to identify other drivers of existing disparities remain a priority.

Continuity and coordination of care in highly selected chronic cancer patients treated with multiple repeat radiation therapy

Introduction and background

As cancer is developing into a chronic disease due to longer survival, continuity and coordination of oncological care are becoming more important for patients. As radiation oncology departments are an integral part of cancer care and as repeat irradiation becomes more commonplace, the relevance of continuity and coordination of care in operating procedures is increasing. This study aims to perform a single-institution analysis of cancer patients in which continuity and coordination of care matters most, namely the highly selected group with multiple repeat course radiotherapy throughout their chronic disease.

Materials and methods

All patients who received at least five courses of radiotherapy at the Department of Radiation Oncology at the University Hospital Zurich from 2011 to 2019 and who were alive at the time of the initiation of this project were included into this study. Patient and treatment characteristics were extracted from the hospital information and treatment planning systems. All patients completed two questionnaires on continuity of care, one of which was designed in-house and one of which was taken from the literature.

Results

Of the 33 patients identified at baseline, 20 (60.6%) participated in this study. A median of 6 years (range 3–13) elapsed between the first and the last visit at the cancer center. The median number of involved primary oncologists at the radiation oncology department was two (range 1–5). Fifty-seven percent of radiation therapy courses were preceded by a tumor board discussion. Both questionnaires showed high levels of experienced continuity of care. No statistically significant differences in experienced continuity of care between groups with more or less than two primary oncologists was found.

Discussion and conclusion

Patients treated with multiple repeat radiation therapy at our department over the past decade experienced high levels of continuity of care, yet further efforts should be undertaken to coordinate care among oncological disciplines in large cancer centers through better and increased use of interdisciplinary tumor boards.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13014-021-01949-5.

Dosimetric Uncertainties in Dominant Intraprostatic Lesion Simultaneous Boost Using Intensity Modulated Proton Therapy

Purpose

While intensity modulated proton therapy can deliver simultaneous integrated boost (SIB) to the dominant intraprostatic lesion (DIL) with high precision, it is sensitive to anatomic changes. We investigated the dosimetric effects from these changes based on pretreatment cone-beam computed tomographic (CBCT) images and identified the most important factors using a multilayer perceptron neural network (MLPNN).

Methods and Materials

DILs were contoured based on coregistered multiparametric magnetic resonance images for 25 previously treated prostate cancer patients. SIB plans were created with (1) prostate clinical target volume − V70 Gy = 98%; (2) DIL − V98 Gy > 95%; and (3) all organs at risk (OARs)"?> within clinical constraints. SIB plans were applied to daily CBCT-based deformed planning computed tomography (CT)"?>. DIL − V98 Gy, bladder/rectum maximum dose (Dmax) and volume changes, femur shifts, and the distance from DIL to organs at riskOARs"?> in both planning computed tomogramsCT"?> and CBCT were calculated. Wilcoxon signed-ranks tests were used to compare the changes. MLPNNs were used to model the change in ΔDIL − V98 Gy > 10% and bladder/rectum Dmax > 80 Gy, and the relative importance factors for the model were provided. The performances of the models were evaluated with receiver operating characteristic curves.

Results

Comparing initial plan to the average from evaluation plans, respectively, DIL − V98 Gy was 89.3% ± 19.9% versus 86.2% ± 21.3% (P = .151); bladder Dmax 71.9 ± 0.6 Gy versus 74.5 ± 2.9 Gy (P < .001); and rectum Dmax 70.1 ± 2.4 Gy versus 74.9 ± 9.1Gy (P = .007). Bladder and rectal volumes were 99.6% ± 39.5% and 112.8% ± 27.2%, respectively, of their initial volume. The femur shift was 3.16 ± 2.52 mm. In the modeling of ΔDIL V98 Gy > 10%, DIL to rectum distance changes, DIL to bladder distance changes, and rectum volume changes ratio are the 3 most important factors. The areas under the receiver operating characteristic curves were 0.89, 1.00, and 0.99 for the modeling of ΔDIL − V98 Gy > 10%, and bladder and rectum Dmax > 80 Gy, respectively.

Conclusions

Dosimetric changes in DIL SIB with intensity modulated proton therapy can be modeled and classified based on anatomic changes on pretreatment images by an MLPNN.

Geriatric assessment with management for older patients with cancer receiving radiotherapy. Protocol of a Norwegian cluster-randomised controlled pilot study

About 50% of patients with cancer are expected to need radiotherapy (RT), and the majority of these are older. To improve outcomes for older patients with cancer, geriatric assessment (GA) with management (GAM) is highly recommended. Evidence for its benefits is still scarce, in particular for patients receiving RT. We report the protocol of a cluster-randomised pilot study designed to test the effect, feasibility and health economic impact of a GAM intervention for patients ≥65 years, referred for palliative or curative RT. The randomising units are municipalities and city districts. The intervention is municipality-based and carried out in collaboration between hospital and municipal health services from the start of RT to eight weeks after the end of RT. Its main constituents are an initial GA followed by measures adapted to individual patients' impairments and needs, systematic symptom assessments and regular follow-up by municipal cancer nurses, appointed to coordinate the patient's care. Follow-up includes at least one weekly phone call, and a house call four weeks after the end of RT. All patients receive an individually adapted physical exercise program and nutritional counselling. Detailed guidelines for management of patients' impairments are provided. Patients allocated to the intervention group will be compared to controls receiving standard care. The primary outcome is physical function assessed by the European Organisation of Research and Treatment of Cancer Quality of Life Questionnaire C-30. Secondary outcomes are global quality of life, objectively tested physical performance and use of health care services. Economic evaluation will be based on a comparison of costs and effects (measured by the main outcome measures). Feasibility will be assessed with mixed methodology, based on log notes and questionnaires filled in by the municipal nurses and interviews with patients and nurses. The study is carried out at two Norwegian RT centres. It was opened in May 2019. Follow-up will proceed until June 2022. Statistical analyses will start by the end of 2021. We expect the trial to provide important new knowledge about the effect, feasibility and costs of a GAM intervention for older patients receiving RT. Trial registration: ClinTrials.gov, ID NCT03881137, initial release 13th of March 2019.

Inhibition of histone acetyltransferase function radiosensitizes CREBBP/EP300 mutants via repression of homologous recombination, potentially targeting a gain of function

Despite radiation forming the curative backbone of over 50% of malignancies, there are no genomically-driven radiosensitizers for clinical use. Herein we perform in vivo shRNA screening to identify targets generally associated with radiation response as well as those exhibiting a genomic dependency. This identifies the histone acetyltransferases CREBBP/EP300 as a target for radiosensitization in combination with radiation in cognate mutant tumors. Further in vitro and in vivo studies confirm this phenomenon to be due to repression of homologous recombination following DNA damage and reproducible using chemical inhibition of histone acetyltransferase (HAT), but not bromodomain function. Selected mutations in CREBBP lead to a hyperacetylated state that increases CBP and BRCA1 acetylation, representing a gain of function targeted by HAT inhibition. Additionally, mutations in CREBBP/EP300 are associated with recurrence following radiation in squamous cell carcinoma cohorts. These findings provide both a mechanism of resistance and the potential for genomically-driven treatment.

Estimation of the Need for Radiation Therapy Services According to the Incidence of Cancer in Colombia to 2035

Purpose

To estimate the supply and demand of current and future radiation therapy services by 2035 for Colombia.

Methods and Materials

The present study was performed by surveying different radiation therapy services identified in Colombia through the Colombian Association of Radiation Oncology. The demand was estimated based on incident cases and published information on the use of radiation therapy by type of cancer. Future demand was estimated under the assumption that incidence rates do not change and therefore the change in the number of cases is due to the change in the age structure of the Colombian population. Sensitivity analyses were conducted on the percentage of radiation therapy use by type of cancer. A Monte Carlo simulation was carried out to estimate the distribution of cases requiring radiation therapy, the amount of equipment, and the number of staff needed for care with the use of this technology.

Results

In total, Colombia has 69 linear accelerators, 2 radiosurgery equipment, 30 high-dose-rate brachytherapy pieces of equipment, 124 radiation therapy oncologists (113 working, 9 not working, and 2 not informed), and 275 radiation therapy technologists as of June 2020. It was estimated that to meet the current cancer burden the country would need a total of 162 radiation therapy oncologists, 121 medical physicists, and 323 radiation therapy technologists and to increase the number of radiation therapy technologists, radiation therapy oncologists, and medical physicists to 491, 246, and 184, respectively, to meet the disease burden by 2035 (73,684-88,743 cases per year).

Conclusions

In Colombia it is estimated that there is a deficit of human resources and technology for radiation therapy; therefore, there is need to investment resources from the public and private sectors to provide timely and quality care to cancer patients requiring this treatment.

The impact of pelvic radiotherapy on the gut microbiome and its role in radiation-induced diarrhoea: a systematic review

Pelvic radiotherapy is the key treatment for pelvic malignancies, usually including pelvic primary tumour lesions and lymphatic drainage areas in the pelvic region. Therefore, the intestinal tract in the radiation field is inevitably damaged, a phenomenon clinically referred to as radiation enteritis, and diarrhoea is the most common clinical symptom of radiation enteritis. Therefore, it is necessary to study the mechanism of radiation-induced diarrhoea. It has been found that the gut microbiome plays an important role in the development of diarrhoea in response to pelvic radiotherapy, and the species and distribution of intestinal microbiota are significantly altered in patients after pelvic radiotherapy. In this study, we searched for articles indexed in the Cochrane Library, Web of Science, EMBASE and PubMed databases in English and CNKI, Wanfang data and SINOMED in Chinese from their inception dates through 13 March 2020 to collect studies on the gut microbiome in pelvic radiotherapy patients. Eventually, we included eight studies: one study report on prostatic carcinoma, five studies on gynaecological carcinoma and two papers on pelvic carcinomas. All studies were designed as self-controlled studies, except for one that compared toxicity to nontoxicity. The results from all the studies showed that the diversity of intestinal flora decreased during and after pelvic radiotherapy, and the diversity of intestinal flora decreased significantly in patients with diarrhoea after radiotherapy. Five studies observed that the community composition of the gut microbiota changed at the phylum, order or genus level before, during, and after pelvic radiotherapy at different time points. In addition, the composition of the gut microbiota before radiotherapy was different between patients with postradiotherapy diarrhoea and those without diarrhoea in five studies. However, relevant studies have not reached consistent results regarding the changes in microbiota composition. Changes in the intestinal flora induced by pelvic radiotherapy and their relationship between changes in intestinal flora and the occurrence of radiation-induced diarrhoea (RID) are discussed in this study, providing a theoretical basis for the causes of RID after pelvic radiotherapy.

Multifunctional MnO2-based nanoplatform-induced ferroptosis and apoptosis for synergetic chemoradiotherapy

Background: Radiosensitizers that can effectively consume glutathione provide broad prospects for enhancing the efficacy and reducing the side effects of radiotherapy. Aim: To explore the potential role of CuS@mSiO₂@MnO₂ nanocomposites in synergetic chemoradiotherapy. Methods: Nanocomposites were characterized by transmission electron microscopy, UV-Vis spectrometry and dynamic light scattering and were loaded with doxorubicin (DOX). The uptake and biodistribution of nanocomposites were observed by CCK8 assay, MRI and confocal laser scanning microscopy. The radiosensitization effect of nanocomposites and nanocomposites/DOX was assessed both in vitro and in vivo. Results: In vitro application of nanocomposites, with an average diameter of 30 nm and ζ-potential of 13.2 ± 0.4 mV, in combination with radiotherapy, depleted glutathione and induced ferroptosis and apoptosis. Nanocomposites/DOX exhibited tumor cell damage in vivo. Conclusion: We propose that this glutathione-depleting nanosystem could be a radiosensitizer as well as a drug transporter.

Repurposing Proton Beam Therapy through Novel Insights into Tumour Radioresistance

Despite improvements in radiotherapy, radioresistance remains an important clinical challenge. Radioresistance can be mediated through enhanced DNA damage response mechanisms within the tumour or through selective pressures exerted by the tumour microenvironment (TME). The effects of the TME have in recent times gained increased attention, in part due to the success of immune modulating strategies, but also through improved understanding of the downstream effects of hypoxia and dysregulated wound healing processes on mediating radioresistance. Although we have a better appreciation of these molecular mechanisms, efforts to address them through novel combination approaches have been scarce, owing to limitations of photon therapy and concerns over toxicity. At the same time, proton beam therapy (PBT) represents an advancement in radiotherapy technologies. However, early clinical results have been mixed and the clinical strategies around optimal use and patient selection for PBT remain unclear. Here we highlight the role that PBT can play in addressing radioresistance, through better patient selection, and by providing an improved toxicity profile for integration with novel agents. We will also describe the developments around FLASH PBT. Through close examination of its normal tissue-sparing effects, we will highlight how FLASH PBT can facilitate combination strategies to tackle radioresistance by further improving toxicity profiles and by directly mediating the mechanisms of radioresistance.

A two-phase approach for the Radiotherapy Scheduling Problem

The Radiotherapy Scheduling Problem (RTSP) focuses on optimizing the planning of radiotherapy treatment sessions for cancer patients. In this paper, we propose a two-phase approach for the RTSP. In the first phase, radiotherapy sessions are assigned to specific linear accelerators (linacs) and days. The second phase then decides the sequence of patients on each day/linac and the specific appointment times. For the first phase, an Integer Linear Programming (IP) model is proposed and solved using CPLEX. For the second phase, a Mixed Integer Linear Programming (MIP) and a Constraint Programming (CP) model are proposed. The test data is generated based on real data from CHUM, a large cancer center in Montréal, Canada, with an average of 3,500 new patients and 40,000 radiotherapy treatments per year. The results show that in the second phase, CP is better at finding good solutions quickly while MIP is better at closing optimality gaps with more run time. Lastly, a simulation is conducted to evaluate the impact of different scheduling strategies on the outcome of the scheduling. Preliminary results show that batch scheduling reduces patients' waiting time and overdue time.

Trends in radiotherapy inpatient admissions in Germany: a population-based study over a 10-year period

Objective

With the increasing complexity of oncological therapy, the number of inpatient admissions to radiotherapy and non-radiotherapy departments might have changed. In this study, we aim to quantify the number of inpatient cases and the number of radiotherapy fractions delivered under inpatient conditions in radiotherapy and non-radiotherapy departments.

Methods

The analysis is founded on data of all hospitalized cases in Germany based on Diagnosis-Related Group Statistics (G-DRG Statistics, delivered by the Research Data Centers of the Federal Statistical Office). The dataset includes information on the main diagnosis of cases (rather than patients) and the performed procedures during hospitalization based on claims of reimbursement. We used linear regression models to analyze temporal trends. The considered data encompass the period from 2008 to 2017.

Results

Overall, the number of patients treated with radiotherapy as inpatients remained constant between 2008 (N = 90,952) and 2017 (N = 88,998). Starting in January 2008, 48.9% of 4000 monthly cases received their treatment solely in a radiation oncology department. This figure decreased to 43.7% of 2971 monthly cases in October 2017. We found a stepwise decrease between December 2011 and January 2012 amounting to 4.3%. Fractions received in radiotherapy departments decreased slightly by 29.3 (95% CI: 14.0–44.5) fractions per month. The number of days hospitalized in radiotherapy departments decreased by 83.4 (95% CI: 59.7, 107.0) days per month, starting from a total of 64,842 days in January 2008 to 41,254 days in 2017. Days per case decreased from 16.2 in January 2008 to 13.9 days in October 2017.

Conclusion

Our data give evidence to the notion that radiotherapy remains a discipline with an important inpatient component. Respecting reimbursement measures and despite older patients with more comorbidities, radiotherapy institutions could sustain a constant number of cases with limited temporal shifts.

Supplementary Information

The online version of this article (10.1007/s00066-021-01829-7) contains supplementary material, which is available to authorized users.

Radiotherapy resources in Africa: an International Atomic Energy Agency update and analysis of projected needs

The number of patients with cancer in Africa has been predicted to increase from 844 279 in 2012 to more than 1·5 million in 2030. However, many countries in Africa still lack access to radiotherapy as a part of comprehensive cancer care. The objective of this analysis is to present an updated overview of radiotherapy resources in Africa and to analyse the gaps and needs of the continent for 2030 in the context of the UN Sustainable Development Goals. Data from 54 African countries on teletherapy megavoltage units and brachytherapy afterloaders were extracted from the Directory for Radiotherapy Centres, an electronic, centralised, and continuously updated database of radiotherapy centres. Cancer incidence and future predictions were taken from the GLOBOCAN 2018 database of the International Agency for Research on Cancer. Radiotherapy need was estimated using a 64% radiotherapy utilisation rate, while assuming a machine throughput of 500 patients per year. As of March, 2020, 28 (52%) of 54 countries had access to external beam radiotherapy, 21 (39%) had brachytherapy capacity, and no country had a capacity that matched the estimated treatment need. Median income was an important predictor of the availability of megavoltage machines: US$1883 (IQR 914-3269) in countries without any machines versus $4485 (3079-12480) in countries with at least one megavoltage machine (p=0·0003). If radiotherapy expansion continues at the rate observed over the past 7 years, it is unlikely that the continent will meet its radiotherapy needs. This access gap might impact the ability to achieve the Sustainable Development Goals, particularly the target to reduce preventable, premature mortality by a third, and meet the target of the cervical cancer elimination strategy of 90% with access to treatment. Urgent, novel initiatives in financing and human capacity building are needed to change the trajectory and provide comprehensive cancer care to patients in Africa in the next decade.

The Modernization of Radiation Therapy Services in Cambodia: A Model of International Collaboration

PURPOSE

Cambodia is a Southeast Asian low-middle-income country with a population of >15 million. In 2020, Cambodia was estimated to have 18,375 new diagnoses of cancer and 12,638 deaths attributable to cancer. Cambodia was estimated to have a deficit of 16 megavoltage machines in 2012. Cambodia's radiation therapy services have suffered through the tumultuous events of the country's history, with intermittent services until the last decade. In recent years, Cambodia has undergone rapid economic growth and, with this, the development of its first comprehensive cancer center, the National Cancer Centre (NCC).

METHODS AND MATERIALS

Planning for NCC began in the early 2000s, with the aim to provide comprehensive care, including modern radiation therapy services, to the public. Funding for the center was supplied primarily by the Cambodian government, assisted by donations from partners including the International Atomic Energy Agency. Training collaborations were formed with international partners, including the Asia-Pacific Radiation Oncology Special Interest Group (APROSIG) of the Royal Australian and New Zealand College of Radiologists and the Asia-Pacific Special Interest Group (APSIG) of the Australasian College of Physical Scientists and Engineers in Medicine.

RESULTS

The main model of APROSIG/APSIG collaboration has been in-country training, including the posting of an Australian medical physicist and radiation therapist in Phnom Penh for a year's duration to oversee a safe and sustainable start to the radiation therapy program. The first linear accelerator patient was treated at NCC in March 2018 and the first brachytherapy patient in September 2018. Since that time, the department has treated to capacity, with very little machine downtime. NCC provides comprehensive cancer services including medical oncology, pediatric oncology, hematology, palliative care, surgical oncology, and nuclear medicine. Several challenges to expanding radiation therapy services currently exist, including human resources and cultural stigma.

CONCLUSION

Despite many decades of tragedy and suffering, Cambodia serves as an example of successful implementation of modern radiation therapy in a low- and middle-income country. The keys to success have included local champions, support of the Ministry of Health, and willingness to embrace collaboration. The pandemic brings yet another challenge to cancer control in Cambodia, and novel training platforms are being explored.

Impact of radiation therapy facility volume on survival in patients with cancer

BACKGROUND

This study examined whether radiation therapy facility volumes correlate with survival after curative intent treatment of solid tumors.

METHODS

The National Cancer Database was queried for patients with solid tumors treated with curative-intent radiation therapy from 2004-2013. Facilities were stratified into 4 volume categories: low, intermediate, high, and very high. Primary cancer sites were divided into neoadjuvant, adjuvant, or definitive radiation subgroups. Kaplan-Meier curves of 5-year postradiation survival probability, stratified by facility volume, were generated with log-rank tests for group comparisons. Cox proportional hazard models were used to evaluate the effect of facility volume on survival, adjusted for multiple covariates.

RESULTS

There were 253,422 patients treated at 1289 facilities: 6231 received neoadjuvant radiation, 147,980 received adjuvant radiation, and 99,211 received definitive radiation without surgery. Among patients receiving neoadjuvant radiation, survival correlated with facility volume for patients with rectal cancer (hazard ratio [HR], 0.75; 95% CI, 0.6-0.94; P = .01). For cancers of the breast and uterus, patients receiving adjuvant radiation at very high-volume facilities (vs low volume) had improved survival (HR, 0.83; 95% CI, 0.77-0.90; P < .001 and HR, 0.77, 95% CI, 0.62-0.97; P = .03, respectively). For patients receiving definitive radiation for prostate, non-small cell lung, pancreas, and head and neck cancer, there was an improvement in survival for patients treated at very high-volume centers (P < .05).

CONCLUSIONS

For select cancer patients, treatment with curative radiation at higher volume facilities is associated with improved survival. In particular, patients receiving radiation therapy in the definitive setting without surgery may benefit most from treatment at high-volume centers.

NeuralDAO: Incorporating neural network generated dose into direct aperture optimization for end-to-end IMRT planning

PURPOSE

Thecurrent practice in intensity-modulated radiation therapy (IMRT) planning almost always includes different dose calculation strategies for plan optimization and final dose verification. The accurate Monte Carlo (MC) dose algorithm is considered to be time-consuming for the optimization. Thus a fast, simplified dose algorithm is used in the optimization. The significant differences between the optimized dose and the delivered dose lead to tediously planning loops and potentially suboptimal solutions. This work aims to develop an IMRT optimization algorithm to minimize the dose discrepancy so that the delivered dose can be optimized in a holistic, end-to-end manner.

METHODS

The proposed algorithm, namely NeuralDAO, integrates a neural dose network into the column generation (CG) direct aperture optimization (DAO) formulation for step-and-shoot IMRT planning. The neural dose network is designed and trained to produce doses of MC-level accuracy within few milliseconds. Its differentiability is fully exploited to compute gradients for identifying potential aperture shapes. A prototype of NeuralDAO was developed in PyTorch and available to the public. Five lung patient cases have been studied. Dosimetric accuracy was compared with the MC dose. Plan quality and time were compared with a state-of-the-art (SoA) dose-correct algorithm. Statistical analysis was performed by Wilcoxon signed-rank test.

RESULTS

The average gamma passing rate at 2 mm/2% is 99.7% between the optimized and delivered doses. The convergence process produced by NeuralDAO is virtually identical to that produced by an MC-based DAO. The average dose calculation time is 12.1 ms for an aperture on GPU. One session of optimization took 10-36 min. Compared with the SoA, better conformity index and homogeneity index were observed for the target. The esophagus was significantly spared. Significant reductions were observed for the replanning number and the planning time.

CONCLUSIONS

A new DAO algorithm based on the neural dose network has been developed. The results suggest that this algorithm minimizes the discrepancy between the optimized and delivered doses, which offers a promising approach to reduce the time and effort required in IMRT planning. This work demonstrates the possibility of applying the neural network in IMRT optimization. It is of great potential to extend this algorithm to other treatment modalities.

Global Radiotherapy: Current Status and Future Directions-White Paper

Recognizing the increase in cancer incidence globally and the need for effective cancer control interventions, several organizations, professional bodies, and international institutions have proposed strategies to improve treatment options and reduce mortality along with minimizing overall incidence. Despite these efforts, an estimated 9.6 million deaths in 2018 was attributed to this noncommunicable disease, making it the second leading cause of death worldwide. Left unchecked, this will further increase in scale, with an estimated 29.5 million new cases and 16.3 million deaths occurring worldwide in 2040. Although it is known and generally accepted that cancer services must include radiotherapy, such access is still very limited in many parts of the world, especially in low- and middle-income countries. After thorough review of the current status of radiotherapy including programs worldwide, as well as achievements and challenges at the global level, the International Atomic Energy Agency convened an international group of experts representing various radiation oncology societies to take a closer look into the current status of radiotherapy and provide a road map for future directions in this field. It was concluded that the plethora of global and regional initiatives would benefit further from the existence of a central framework, including an easily accessible repository through which better coordination can be done. Supporting this framework, a practical inventory of competencies needs to be made available on a global level emphasizing the knowledge, skills, and behavior required for a safe, sustainable, and professional practice for various settings. This white paper presents the current status of global radiotherapy and future directions for the community. It forms the basis for an action plan to be developed with professional societies worldwide.

Radiation Oncology Applications in Plastic and Reconstructive Surgery: A Nonsystematic Review of Concepts and Principles

SUMMARY

Careful consideration of radiotherapy can determine the success of reconstructive therapy. There is a broad spectrum of radiotherapy modalities, both benign and malignant. Delivery mechanisms differ in the physical design, setup, radiation source, administrable dosage, and mode of delivery. This range of options allows radiation oncologists to tailor individualized treatment; however, radiotherapy concepts can be challenging for nonspecialists. The purpose of this article is to review general radiation oncology concepts, including essential equipment and radiobiology, and provide plastic surgeons with a basic conceptual understanding to facilitate effective multidisciplinary collaboration with radiation oncologists.

Radiation Oncology in the Land of the Pyramids: How Sudan Continues to Push the Frontiers of Cancer Care in Eastern Africa

When faced with illness, Sudanese patients have traditionally relied primarily on folklore healers. In the recent past, Sudan increased its health care spending and placed ever-greater importance on medical education. Although traditional remedies still play an important role, Sudanese patients increasingly consult conventional medicine. Not only infectious diseases but also a rising burden of noncommunicable conditions, including cancer, represent major health care challenges. Therefore, Sudan will need to make the best out of the limited resources available and further increase investment in health care to confront these trends successfully. Sudan was one of the first African countries to recognize the importance of radiation oncology in multidisciplinary cancer care and began investing in it in the 1960s. Today, there are 4 comprehensive cancer centers in the country, which offer radiation therapy and employ 10 radiation therapy machines for a population of about 45 million people. This proportion is an indication that Sudan still has an underfunded health care system with a lack of infrastructure and human resources. The present manuscript intends to provide a well-rounded overview of radiation oncology in Sudan today.

Can the Adoption of Hypofractionation Guidelines Expand Global Radiotherapy Access? An Analysis for Breast and Prostate Radiotherapy

PURPOSE

The limited radiotherapy resources for global cancer control have resulted in increased interest in developing time- and cost-saving innovations to expand access to those resources. Hypofractionated regimens could minimize cost and increase access for limited-resource countries. In this investigation, we estimated the percentage cost-savings per radiotherapy course and increased radiotherapy access in African countries after adopting hypofractionation for breast and prostate radiotherapy. For perspective, results were compared with high-income countries.

METHODS

The cost and course of breast and prostate radiotherapy for conventional and hypofractionated regimens in low-resource facilities were calculated using the Radiotherapy Cost Estimator tool developed by the International Atomic Energy Agency (IAEA) and then compared with another activity-based costing model. The potential maximum cost savings in each country over 7 years for breast and prostate radiotherapy were then estimated using cancer incidence data from the Global Cancer Observatory database with use rates applied. The increase in radiotherapy access was estimated by current national capacities from the IAEA directory.

RESULTS

The estimated cost per course of conventional and hypofractionated regimens were US$2,232 and $1,339 for breast treatment, and $3,389 and $1,699 for prostate treatment, respectively. The projected potential maximum cost savings with full hypofractionation implementation were $1.1 billion and $606 million for breast and prostate treatment, respectively. The projected increase of radiotherapy access due to implementing hypofractionation varied between +0.3% to 25% and +0.4% to 36.0% for breast and prostate treatments, respectively.

CONCLUSION

This investigation demonstrates that adopting hypofractionated regimens as standard treatment of breast and prostate cancers can result in substantial savings and increase radiotherapy access in developing countries. Given reduced delivery cost and treatment times, we anticipate a substantial increase in radiotherapy access with additional innovations that will allow progressive hypofractionation without compromising quality.

Contemporary radiotherapy: present and future

Oncology care is increasingly a multidisciplinary endeavour, and radiation therapy continues to have a key role across the disease spectrum in nearly every cancer. However, the field of radiation oncology is still one of the most poorly understood of the cancer disciplines. In this Review, we attempt to summarise and contextualise developments within the field of radiation oncology for the non-radiation oncologist. We discuss advancements in treatment technologies and imaging, followed by an overview of the interplay with advancements in systemic therapy and surgical techniques. Finally, we review new frontiers in radiation oncology, including advances within the metastatic disease continuum, reirradiation, and emerging types of radiation therapy.

Radiotherapy is associated with a deletion signature that contributes to poor outcomes in patients with cancer

Ionizing radiation causes DNA damage and is a mainstay for cancer treatment, but understanding of its genomic impact is limited. We analyzed mutational spectra following radiotherapy in 190 paired primary and recurrent gliomas from the Glioma Longitudinal Analysis Consortium and 3,693 post-treatment metastatic tumors from the Hartwig Medical Foundation. We identified radiotherapy-associated significant increases in the burden of small deletions (5-15 bp) and large deletions (20+ bp to chromosome-arm length). Small deletions were characterized by a larger span size, lacking breakpoint microhomology and were genomically more dispersed when compared to pre-existing deletions and deletions in non-irradiated tumors. Mutational signature analysis implicated classical non-homologous end-joining-mediated DNA damage repair and APOBEC mutagenesis following radiotherapy. A high radiation-associated deletion burden was associated with worse clinical outcomes, suggesting that effective repair of radiation-induced DNA damage is detrimental to patient survival. These results may be leveraged to predict sensitivity to radiation therapy in recurrent cancer.

Impact of the phytochemicals cocktail "breast safeguard" in regulating the interplay between redox signalling and murine adenocarcinoma cell proliferation, survival and angiogenesis

Phytochemicals are natural plant extracts with a potent antioxidant, anti-inflammatory and anticancer characteristics by acting as a cell signalling modulator. This study aims to evaluate the effect of a commercial cocktail of phytochemicals "Breast safeguard" (BSG) in upregulating the expression of antioxidant enzymes to counteract signalling pathways that promote Ehrlich cells progression. The potent antioxidant activity and total phenolics and flavonoids contents of BSG was chemically validated, BSG treated mice showed a significant reduction at the tumor size, along with significant reduction in the expression of prognostic markers CEA and TNFα and induction of cell cycle arrest at G1/S phase as well as downregulation of Ki67. BSG supplementation significantly diminished H2O2, NO, MDA levels and upregulated the expression of SOD, CAT, GPx and GSH antioxidant enzymes in plasma and tumor tissues. BSG treatment markedly activated P53/Bax/Bcl2/c-caspase 3 signalling for cell apoptosis and attenuated the expression of antiapoptotic survivin protein. Meanwhile, BSG significantly diminished the expression of VEGF as an indication of angiogenesis inhibition. In conclusion, BSG exerted a significant upregulation of antioxidant enzymes which may be involved in upregulating P53/Bax/c-caspase 3 expression and attenuation of cell proliferation and angiogenesis.

Does a communication skills program enable symptom and distress screening?: The impact of training on radiation therapists' confidence, knowledge, and use of distress screening

INTRODUCTION

Due to the prevalence of distress following a cancer diagnosis, routine symptom and distress screening is recommended as best practice. RTs perceive psychosocial support and screening to be part of their role, however feel they lack the education and skills to perform this confidently. The study aimed to evaluate the impact of providing communication skills training (RT Prepare CST) on the perceived barriers, knowledge, attitude, role, and confidence of radiation therapists (RTs) in using routine symptom and distress screening.

METHODS

A single-arm, pre-post intervention design was implemented. All RTs at one regional and one rural centre participated in RT Prepare CST. RTs completed a questionnaire: pre-intervention (T1); immediately post-intervention (T2); and, three months post-intervention (T3). Cochran's Q and McNemar's tests for non-parametric data were conducted to compare outcomes over time.

RESULTS

Of 39 RTs approached, 37 (95%) consented to participate with 36 (92%) completing questionnaires at all three time points. Significant and sustained improvements post-intervention were noted from T1-T3 including: confidence in describing the PROMPT-Care tool to patients (p=0.002), discussing psychosocial issues (p=0.014); recognising signs of anxiety/depression (p<0.001); dealing with signs of anxiety (p=0.002), depression (p=0.015) and distress (p=0.008) as well as agreeing 'the tool is useful in identifying psychosocial problems' (p=0.029).

CONCLUSIONS

RT Prepare CST was effective in increasing confidence, knowledge and attitudes of RTs in the psychosocial care of patients with a change in RT behaviour noted by a significant increase in the number of patients screened following the intervention. Providing routine CST and emotional cues training to RTs enhances their ability to care for patients holistically, equipping them with skills to be included within a psychosocial model of care. Engaged leadership and role models are essential to sustain the learnings from education programs and provide an environment to discuss and define roles within radiation therapy departments.

Surveying the Challenges to Improve Linear Accelerator-based Radiation Therapy in Africa: a Unique Collaborative Platform of All 28 African Countries Offering Such Treatment

Radiation therapy is a critical component for curative and palliative treatment of cancer and is used in more than half of all patients with cancer. Yet there is a global shortage of access to this treatment, especially in Sub-Saharan Africa, where there is a shortage of technical staff as well as equipment. Linear accelerators (LINACs) offer state-of-the-art treatment, but this technology is expensive to acquire, operate and service, especially for low- and middle-income countries (LMICs), and often their harsh environment negatively affects the performance of LINACs, causing downtime. A global initiative was launched in 2016 to address the technology and system barriers to providing radiation therapy in LMICs through the development of a novel LINAC-based radiation therapy system designed for their challenging environments. As the LINAC prototype design phase progressed, it was recognised that additional information was needed from LMICs on the performance of LINAC components, on variables that may influence machine performance and their association, if any, with equipment downtime. Thus, a survey was developed to collect these data from all countries in Africa that have LINAC-based radiation therapy facilities. In order to understand the extent to which these performance factors are the same or different in high-income countries, facilities in Canada, Switzerland, the UK and the USA were invited to participate in the survey, as was Jordan, a middle-income country. Throughout this process, LMIC representatives have provided input on technology challenges in their respective countries. This report presents the method used to conduct this multilevel study of the macro- and microenvironments, the organisation of departments, the technology, the training and the service models that will provide input into the design of a LINAC prototype for a LINAC-based radiation therapy system that will improve access to radiation therapy and thus improve cancer treatment outcomes. It is important to note that new technology should be introduced in a contextual manner so as not to disrupt existing health systems inadvertently, especially with regards to existing staffing, infrastructure and socioeconomic issues. A detailed analysis of data is underway and will be presented in a follow-up report. Selected preliminary results of the study are the observation that LINAC-based facilities in LMICs experience downtime associated with failures in multileaf collimators and vacuum pumps, as well as power instability. Also, that there is a strong association of gross national product per capita with the number of LINACs per population.

Increased Radiosensitivity of Solid Tumors Harboring ATM and BRCA1/2 Mutations

Purpose

Preclinical data indicate that response to radiotherapy (RT) depends on DNA damage repair. In this study, we investigated the role of mutations in genes related to DNA damage repair in treatment outcome after RT.

Materials and Methods

Patients with solid tumor who participated in next generation sequencing panel screening using biopsied tumor tissue between October 2013 and February 2019 were reviewed and 97 patients that received RT were included in this study. Best response to RT and the cumulative local recurrence rate (LRR) were compared according to absence or presence of missense, nonsense, and frameshift mutations in ATM and/or BRCA1/2.

Results

Of the 97 patients, five patients harbored mutation only in ATM, 22 in only BRCA1/2, and six in both ATM and BRCA1/2 (ATM^mtBRCA^mt). Propensity score matching was performed to select the control group without mutations (ATM^wtBRCA^wt, n=33). In total, 90 RT-treated target lesions were evaluated in 66 patients. Highest objective response rate of 80% was observed in ATM^mtBRCA^mt lesions (p=0.007), which was mostly durable. Furthermore, the cumulative 1-year LRR was the lowest in ATM^mtBRCA^mt lesions and the highest in ATM^wtBRCA^wt lesions (0% vs. 47.9%, p=0.008). RT-associated toxicities were observed in 10 treatments with no significant difference among the subgroups (p=0.680).

Conclusion

Tumors with ATM and BRCA1/2 mutations exhibited superior tumor response and local control after RT compared to tumors without these mutations. The results are hypothesis generating and suggest the need for integrating the tumor mutation profile of DNA repair genes during treatment planning.

Do radiation therapists feel able to routinely screen for symptoms and distress in people with cancer: barriers impacting practice

INTRODUCTION

This study aimed to evaluate radiation therapists' (RTs) perceptions regarding the perceived barriers, knowledge, attitudes, confidence and role in administering an electronic screening tool to routinely screen for cancer patients' symptoms and distress.

METHODS

RTs at two radiation therapy departments completed a cross-sectional paper/pen survey to assess their demographic and workplace characteristics, perceptions of barriers, knowledge, attitudes, confidence and opinion of their role in symptom and distress screening. Responses were evaluated using simple frequencies and free-text responses using thematic analysis.

RESULTS

Of 39 RTs approached, 37 (95%) participated. The majority had not previously attended any emotional cues (77%) or psychosocial training (86%); 68% reported confidence discussing psychosocial concerns and recognising signs of anxiety and depression in patients, and 65% felt discussing patients' psychosocial concerns was part of their role. Administering the tool to patients was agreed to be the role of RTs by 38% of participants. Lack of education about psychosocial issues was the highest-ranked barrier to delivering the patient screening tool, with 74% of RTs responding 'it has made it difficult'.

CONCLUSION

Whilst RTs are willing to play a role in patients' psychosocial support, they do not feel able to fulfil this role adequately because they lacked knowledge and confidence to administer symptom and distress screening. This research has highlighted the need for RT education on psychosocial concerns and recognising and responding to emotional cues. Understanding the impact education may have on the knowledge, attitude, confidence and role of RTs performing routine symptom and distress screening is required.