FLASH radiotherapy: A new milestone in the field of cancer radiotherapy

Radiotherapy plays a pivotal role in the control and eradication of tumors, but it can also induce radiation injury to surrounding normal tissues while targeting tumor cells. In recent years, FLASH-Radiotherapy (FLASH-RT) has emerged as a cutting-edge research focus in the field of radiation therapy. By delivering high radiation doses to the treatment target in an ultra-short time, FLASH-RT produces the FLASH effect, which reduces the toxicity to normal tissues while achieving comparable tumor control efficacy to conventional radiotherapy. This review provides a brief overview of the development history of FLASH-RT and its impact on tumor control. Additionally, it focuses on introducing the protective effects and molecular mechanisms of this technology on various normal tissues, as well as exploring its synergistic effects when combined with other tumor therapies. Importantly, this review discusses the challenges faced in translating FLASH-RT into clinical practice and outlines its promising future applications.

Radiation levels outside a patient undergoing177Lu-PSMA radioligand therapy

Understanding the spatial distribution of radiation levels outside of a patient undergoing177Lu radioligand therapy is not only helpful for conducting correct tests for patient release, but also useful for estimation of its potential exposure to healthcare workers, caregivers, family members, and the general public. In this study, by mimicking the177Lu-labeled prostate-specific membrane antigen radioligand therapy for prostate cancers in an adult male, the spatial distribution of radiation levels outside of the phantom was simulated based on the Monte Carlo software of Particle and Heavy Ion Transport System, and verified by a series of measurements. Moreover, the normalized dose rates were further formulized on the three transverse planes representing the heights of pelvis, abdomen and chest. The results showed that the distributions of radiation levels were quite complex. Multi-directional and multi-height measurements are needed to ensure the external dose rate to meet the release criteria. In general, the radiation level was higher at the horizontal plane where the source was located, and the levels in front and behind of the body were higher than those of the left and right sides at the same height. The ratio of simulated dose rates to measured ones ranged from 0.82 to 1.19 within 1 m away from the body surface in all directions. Based on the established functions, the relative root mean square deviation between the calculated and simulated values were 0.21, 0.25 and 0.23 within a radius of 1 m on the pelvis, abdomen and chest transverse planes, respectively. It is expected that the results of this study would be helpful for guiding the test of extracorporeal radiation to determine the patient's release, and of benefit to estimate the radiation exposure to others.

Established advanced practice roles in radiation therapy: A scoping review

Advanced practitioners are healthcare professionals that are highly skilled with a particular area of expertise. These roles have been successfully implemented in many healthcare settings, improving efficiency of the service, as well as enhancing the standard of care received by patients. Although advanced practice roles have been implemented in some radiation therapy departments, their implementation have yet to be facilitated in the majority of countries. The purpose of this review is to scope the literature available regarding established advanced practice roles in radiation therapy. The PRISMA strategy for the identification of relevant literature was adhered to. Two data bases, EMBASE and PubMed, were searched using combinations of the key words 'Advanced', 'Practice', 'APRT', 'Radiation', 'Therapy' and 'Radiotherapy'. Exclusion criteria were applied, and citation lists were also screened for additional relevant sources, including grey literature sources. A total of 35 relevant sources were identified that discussed advanced practice radiation therapy roles in the United Kingdom, Singapore, Canada, Australia and the USA. Means of role establishment and scope of practice were defined, and a number of advantages and challenges for advanced practice radiation therapist roles were identified. There are many benefits of implementing advanced practice roles in radiation therapy departments. Though the implementation of these roles can be challenging, the existing evidence indicates that it would be beneficial for the patient, the radiation therapist and the department as a whole. A more systematic approach, including reporting of quantitative outcomes may assist in the more widespread implementation of these roles.

Common Sense (Radiation) Oncology: Redefining targets in radiotherapy

In 2023, the Common Sense Oncology (CSO) movement was launched with the goal of recalibrating cancer care to focus on outcomes that matter to patients. We extend the three CSO pillars - evidence generation, interpretation and communication - to radiation oncology and advocate for better evidence demonstrating the value of our modality.

Treatment intensification strategies for men undergoing definitive radiotherapy for high-risk prostate cancer

PURPOSE

Treatment intensification of external beam radiotherapy (EBRT) plays a crucial role in the treatment of high-risk prostate cancer.

METHODS

We performed a critical narrative review of the relevant literature and present new developments in evidence-based treatment intensification strategies.

RESULTS

For men with high-risk prostate cancer, there is strong evidence to support prolonging androgen deprivation therapy (ADT) to 18-36 months and escalating the dose to the prostate using a brachytherapy boost. A potentially less toxic alternative to a brachytherapy boost is delivering a focal boost to dominant intraprostatic lesions using EBRT. In patients who meet STAMPEDE high-risk criteria, there is evidence to support adding a second-generation anti-androgen agent, such as abiraterone acetate, to long-term ADT. Elective pelvic lymph node irradiation may be beneficial in select patients, though more prospective data is needed to elucidate the group of patients who may benefit the most. Tumor genomic classifier (GC) testing and advanced molecular imaging will likely play a role in improving patient selection for treatment intensification as well as contribute to the evolution of treatment intensification strategies for future patients.

CONCLUSION

Treatment intensification using a combination of EBRT, advanced hormonal therapies, and brachytherapy may improve patient outcomes and survival in men with high-risk prostate cancer. Shared decision-making between patients and multidisciplinary teams of radiation oncologists, urologists, and medical oncologists is essential for personalizing care in this setting and deciding which strategies make sense for individual patients.

Possible mechanisms and simulation modeling of FLASH radiotherapy

FLASH radiotherapy (FLASH-RT) has great potential to improve patient outcomes. It delivers radiation doses at an ultra-high dose rate (UHDR: ≥ 40 Gy/s) in a single instant or a few pulses. Much higher irradiation doses can be administered to tumors with FLASH-RT than with conventional dose rate (0.01-0.40 Gy/s) radiotherapy. UHDR irradiation can suppress toxicity in normal tissues while sustaining antitumor efficiency, which is referred to as the FLASH effect. However, the mechanisms underlying the effects of the FLASH remain unclear. To clarify these mechanisms, the development of simulation models that can contribute to treatment planning for FLASH-RT is still underway. Previous studies indicated that transient oxygen depletion or augmented reactions between secondary reactive species produced by irradiation may be involved in this process. To discuss the possible mechanisms of the FLASH effect and its clinical potential, we summarized the physicochemical, chemical, and biological perspectives as well as the development of simulation modeling for FLASH-RT.

2023 Updated MASCC/ESMO Consensus Recommendations: prevention of radiotherapy- and chemoradiotherapy-induced nausea and vomiting

PURPOSE

Radiotherapy and chemoradiotherapy-induced nausea and vomiting (RINV and C-RINV) are common and distressing, and there is a need for guidance for clinicians to provide up to date optimal antiemetic prophylaxis and treatment. Through a comprehensive review of the literature concerning RINV and C-RINV, this manuscript aims to update the evidence for antiemetic prophylaxis and rescue therapy and provide a new edition of recommendations for the MASCC/ESMO antiemetic guidelines for RINV and C-RINV.

METHODS

A systematic review of the literature including data published from May 1, 2015, to January 31, 2023, was performed. All authors assessed the literature.

RESULTS

The searches yielded 343 references; 37 met criteria for full article review, and 20 were ultimately retained. Only one randomized study in chemoradiation had the impact to provide new recommendations for the antiemetic guideline. Based on expert consensus, it was decided to change the recommendation for the "low emetic risk" category from "prophylaxis or rescue" to "rescue" only, while the drugs of choice remain unchanged.

CONCLUSION

As for the previous guideline, the serotonin receptor antagonists are still the cornerstone in antiemetic prophylaxis of nausea and vomiting induced by high and moderate emetic risk radiotherapy. The guideline update provides new recommendation for the management of C-RINV for radiotherapy and concomitant weekly cisplatin. To avoid overtreatment, antiemetic prophylaxis is no longer recommended for the "low emetic risk" category.

Common Variants in Osteopontin and CD44 Genes as Predictors of Treatment Outcome in Radiotherapy and Chemoradiotherapy for Non-Small Cell Lung Cancer

Osteopontin (OPN)-CD44 signaling plays an important role in promoting tumor progression and metastasis. In cancer, OPN and CD44 overexpression is a marker of aggressive disease and poor prognosis, and correlates with therapy resistance. In this study, we aimed to evaluate the association of single nucleotide polymorphisms (SNPs) in the OPN and CD44 genes with clinical outcomes in 307 non-small cell lung cancer (NSCLC) patients treated with radiotherapy or chemoradiotherapy. The potential impact of the variants on plasma OPN levels was also investigated. Multivariate analysis showed that OPN rs11730582 CC carriers had a significantly increased risk of death (p = 0.029), while the CD44 rs187116 A allele correlated with a reduced risk of locoregional recurrence (p = 0.016) in the curative treatment subset. The rs11730582/rs187116 combination was associated with an elevated risk of metastasis in these patients (p = 0.016). Furthermore, the OPN rs1126772 G variant alone (p = 0.018) and in combination with rs11730582 CC (p = 7 × 10-5) was associated with poor overall survival (OS) in the squamous cell carcinoma subgroup. The rs11730582 CC, rs187116 GG, and rs1126772 G, as well as their respective combinations, were independent risk factors for unfavorable treatment outcomes. The impact of rs11730582-rs1126772 haplotypes on OS was also observed. These data suggest that OPN and CD44 germline variants may predict treatment effects in NSCLC.

A JROD survey: nationwide overview of radiotherapy data from 2015 to 2021

The purpose of this survey was to examine the status of radiotherapy in Japan based on the cases registered in the Japanese Radiation Oncology Database (JROD), from 2015 to 2021, and to provide basic data to help improve the usefulness of the JROD in the future. The study population consisted of patients who underwent radiotherapy between 2014 and 2020 and did not opt out of the study. The survey item data analyzed in this study were entered into the database at each radiotherapy institution by referring to medical records from the preceding year. Our results show that the number of registered radiotherapy institutions and cases increased by ~50% in 2019 compared to those in 2015 (to 113 institutions and 60 575 cases, respectively). Among the survey item categories, the registration rate was lowest for prognostic information (13.9% on average over the 7-year period). In terms of the Japanese Society for Radiation Oncology disease site, the breast; lung, trachea and mediastinum and urogenital sites accounted for >50% of the total cases. The average survival and mortality rates over the 7-year study period were 67.4 and 17.4%, respectively. The X-ray radiotherapy completion rate exceeded 90% for all years and across all disease categories. 192Ir-based brachytherapy and 223Ra-based radionuclide therapy accounted for an average of 61.9 and 44.6%, respectively, of all corresponding cases over the 7-year period. In conclusion, this survey enables us to infer the actual status of radiotherapy in Japan based on the analysis of relevant nationwide data.

Monocrystalline diamond detector for online monitoring during synchrotron microbeam radiotherapy

Microbeam radiation therapy (MRT) is a radiotherapy technique combining spatial fractionation of the dose distribution on a micrometric scale, X-rays in the 50-500 keV range and dose rates up to 16 × 103 Gy s-1. Nowadays, in vivo dosimetry remains a challenge due to the ultra-high radiation fluxes involved and the need for high-spatial-resolution detectors. The aim here was to develop a striped diamond portal detector enabling online microbeam monitoring during synchrotron MRT treatments. The detector, a 550 µm bulk monocrystalline diamond, is an eight-strip device, of height 3 mm, width 178 µm and with 60 µm spaced strips, surrounded by a guard ring. An eight-channel ASIC circuit for charge integration and digitization has been designed and tested. Characterization tests were performed at the ID17 biomedical beamline of the European Synchrotron Radiation Facility (ESRF). The detector measured direct and attenuated microbeams as well as interbeam fluxes with a precision level of 1%. Tests on phantoms (RW3 and anthropomorphic head phantoms) were performed and compared with simulations. Synchrotron radiation measurements were performed on an RW3 phantom for strips facing a microbeam and for strips facing an interbeam area. A 2% difference between experiments and simulations was found. In more complex geometries, a preliminary study showed that the absolute differences between simulated and recorded transmitted beams were within 2%. Obtained results showed the feasibility of performing MRT portal monitoring using a microstriped diamond detector. Online dosimetric measurements are currently ongoing during clinical veterinary trials at ESRF, and the next 153-strip detector prototype, covering the entire irradiation field, is being finalized at our institution.

A systematic review and meta-analysis

BACKGROUND AND PURPOSE

The addition of cyclin-dependent kinase 4/6 inhibitors (CDK4/6i) to endocrine therapy in hormone receptor-positive (HR+) human epidermal growth factor 2-negative (HER2-) breast cancer has led to practice-changing improvements in overall survival. However, there are conflicting data concerning the safety of CDK4/6i combination with radiotherapy, and no consensus guidelines exist to guide practice. We conducted a meta-analysis to assess the safety and feasibility of CDK4/6i treatment with radiotherapy.

MATERIALS AND METHODS

A comprehensive search was performed in PubMed/MEDLINE, Web of Science, and Scopus, for studies in advanced/metastatic breast cancer receiving CDK4/6i and radiotherapy with the provided safety data on the occurrence of toxicity. The main outcomes were safety (grade 3-5 adverse events), CDK 4/6i dose reduction, and the discontinuation rate due to toxicity.

RESULTS

Fifteen studies comprising 1133 patients with HR+/HER2- breast cancer patients were included. Among them, 617 pts received CDK4/6i and radiotherapy; the median follow-up was 17.0 months (IQR 9.2 - 18.0), and the median age was 58.8 years (IQR 55.5---62.5). The pooled prevalence of severe hematologic toxicity was 29.4% (95% CI 14.0% - 47.4%; I2 = 93%; τ2 = 0.084; p < 0.01 and severe non-hematologic toxicity was 2.8% (95% CI 1.1% - 4.8%; I2 = 0%; τ2 = 0.0; p = 0.67). The pooled prevalence of CDK4/6i dose reduction was 24.0% (95% CI 11.1% - 39.4%; I2 = 90%; τ2 = 0.052; p < 0.01) with no difference between CDK4/6i plus RT vs. CDK4/6i (odds ratio of 0.934; 95% CI 0.66 - 1.33; I2 = 0%; τ2 = 0.0; p = 0.56). The pooled prevalence of CDK4/6i discontinuation due to toxicity was 2.3% (95% CI 0.4% - 5.2%; I2 = 23%; τ2 = 0.002; p = 0.24).

CONCLUSION

The findings of this study suggest that radiotherapy in addition to CDK4/6i treatment in breast cancer patients is generally safe and well tolerated and remains a viable treatment option.

Clinical perspectives on dosimetry in molecular radiotherapy

Molecular radiotherapy is the use of systemically administered unsealed radioactive sources to treat cancer. Theragnostics is the term used to describe paired radiopharmaceuticals localising to a specific target, one optimised for imaging, the other for therapy. For many decades, molecular radiotherapy has developed empirically. Standard administered activity schedules have been used without the prior estimation of the resulting tumour radiation absorbed dose by theragnostic imaging, or its subsequent measurement by serial scanning. This pragmatic approach has benefited many patients, however others who should have benefited have failed to do so as the radiation absorbed dose in the tumour was suboptimal. The accurate prediction and measurement of tumour and organ at risk radiation absorbed doses allows treatment to be personalised, and offers the prospect of improved clinical outcomes. To deliver this for all molecular radiotherapy patients would require not only a significant financial investment in equipment and skilled personnel, but also a change in attitude of those who believe that simple - or simplistic - schedules are easier to deliver, and that accurate dosimetry is too much trouble. Further clinical studies are required to demonstrate beyond doubt that the advantages of individualised treatment planning outweigh the inconvenience, and that the expense is justified by enhanced results.

A national repository of complete radiotherapy plans: design, Results, and experiences

BACKGROUND

Previously, many radiotherapy (RT) trials were based on a few selected dose measures. Many research questions, however, rely on access to the complete dose information. To support such access, a national RT plan database was created. The system focuses on data security, ease of use, and re-use of data. This article reports on the development and structure, and the functionality and experience of this national database.

METHODS AND MATERIALS

A system based on the DICOM-RT standard, DcmCollab, was implemented with direct connections to all Danish RT centres. Data is segregated into any number of collaboration projects. User access to the system is provided through a web interface. The database has a finely defined access permission model to support legal requirements.

RESULTS

Currently, data for more than 14,000 patients have been submitted to the system, and more than 50 research projects are registered. The system is used for data collection, trial quality assurance, and audit data set generation.Users reported that the process of submitting data, waiting for it to be processed, and then manually attaching it to a project was resource intensive. This was accommodated with the introduction of triggering features, eliminating much of the need for users to manage data manually. Many other features, including structure name mapping, RT plan viewer, and the Audit Tool were developed based on user input.

CONCLUSION

The DcmCollab system has provided an efficient means to collect and access complete datasets for multi-centre RT research. This stands in contrast with previous methods of collecting RT data in multi-centre settings, where only singular data points were manually reported. To accommodate the evolving legal environment, DcmCollab has been defined as a 'data processor', meaning that it is a tool for other research projects to use rather than a research project in and of itself.

The dose-related plateau effect of surviving fraction in normal tissue during the ultra-high-dose-rate radiotherapy

Objective.Ultra-high-dose-rate radiotherapy, referred to as FLASH therapy, has been demonstrated to reduce the damage of normal tissue as well as inhibiting tumor growth compared with conventional dose-rate radiotherapy. The transient hypoxia may be a vital explanation for sparing the normal tissue. The heterogeneity of oxygen distribution for different doses and dose rates in the different radiotherapy schemes are analyzed. With these results, the influence of doses and dose rates on cell survival are evaluated in this work.Approach.The two-dimensional reaction-diffusion equations are used to describe the heterogeneity of the oxygen distribution in capillaries and tissue. A modified linear quadratic model is employed to characterize the surviving fraction at different doses and dose rates.Main results.The reduction of the damage to the normal tissue can be observed if the doses exceeds a minimum dose threshold under the ultra-high-dose-rate radiation. Also, the surviving fraction exhibits the 'plateau effect' under the ultra-high dose rates radiation, which signifies that within a specific range of doses, the surviving fraction either exhibits minimal variation or increases with the dose. For a given dose, the surviving fraction increases with the dose rate until tending to a stable value, which means that the protection in normal tissue reaches saturation.Significance.The emergence of the 'plateau effect' allows delivering the higher doses while minimizing damage to normal tissue. It is necessary to develop appropriate program of doses and dose rates for different irradiated tissue to achieve more efficient protection.

Artificial intelligence and Italian culture: an understanding of how artificial intelligence can transform the radiation therapy landscape

The aim is to support the perception of artificial intelligence in the radiation therapy landscape.

Beam Focal Spot Offset Determination for Linear Accelerators: A Phantom less Method

The effectiveness of radiotherapy treatment is influenced by the position of beam focal spot; therefore, it is important to verify the beam focal spot periodically. In this study the beam focal spot offset is measured using an electronic portal imaging (EPID) based technique and co- rotational penumbra modulation technique(CPM).

MATERIALS AND METHODS

This method utilizes one set of jaws and the multileaf collimator (MLC) to form a symmetric field and then a 180o collimator rotation was utilized to determine the radiation isocenter defined by the jaws and the MLC, respectively. The difference between these two isocentres is then directly correlated with the beam focal spot offset of the linear accelerator. In the current study, the method has been used for Varian ClinaciX and Elekta Versa HD linear accelerators. Since an Elektalinac with the Agility® head does not have two set of jaws, a modified method that making use of one set of diaphragms, the MLC and a full 360o collimator rotation is implemented.

RESULT

The method is validated against CPM and found to be in agreement within 0.00923± 0.009360 mm ( SD) also the method has been found to be reproducible to within 0.0365 mm (SD).

CONCLUSION

The method could be used for routine quality assurance (QA) to ensure that the beam focal spot offset is in tolerance.

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.

Clinical Outcomes of Radiotherapy for Stage 1 Glottic Carcinoma: Comparing Accelerated Hyperfractionation and Once-daily Fractionation

BACKGROUND/AIM

Accelerated hyperfractionation (AHF) is used in head and neck cancer to improve the local control (LC) rate, but reports of outcomes for early-stage GC are limited. The outcomes of radiotherapy (RT) for stage 1 glottic carcinoma (GC) were retrospectively analyzed, comparing AHF and once-daily fractionation (ODF) using 2.0-2.4 Gy.

PATIENTS AND METHODS

A total of 102 patients with stage 1 GC underwent RT alone between 2007 and 2021, with 43 in the AHF group and 59 in the ODF group. A p-value less than 0.05 was considered to indicate a significant difference.

RESULTS

The 5-year LC rate was 98% in the AHF group and 91% in the ODF group (p=0.19). During RT, significantly more patients in the AHF group required opioids due to mucositis than in the ODF group (74% vs. 25%, p<0.001), and the rate of aspiration pneumonia tended to be higher in the AHF group than in the ODF group (7% vs. 0%, p=0.072).

CONCLUSION

There was no difference in the LC rate between AHF and ODF for stage 1 GC. Moreover, the AHF group required opioids at a higher rate and tended to have a higher risk of developing aspiration pneumonia.

[Current Management of Basal Cell Carcinoma]

For the management of basal cell carcinoma, the primary performance of a risk stratification, which is decisive for the further diagnostic and therapeutic steps, is becoming increasingly important.Various non-invasive methods are available to confirm the clinical diagnosis. Histological confirmation of the diagnosis is recommended in unclear cases. In poorly displaced lesions, preoperative cross-sectional imaging of the tumor area should be performed to exclude osseous infiltration.The gold standard in treatment remains surgery, which should be performed by means of micrographically controlled surgery if possible. In addition, there are other therapeutic methods such as radiotherapy or a number of topical therapy options (photodynamic therapy, cryotherapy or application of 5-fluorouracil or imiquimod), which can be used in certain cases. Also for advanced or metastatic basal cell carcinoma, effective drugs are available in the form of the hedgehog inhibitors, for which there is now several years of application experience with regard to efficacy and handling of adverse events. With the PD-1 inhibitor cemiplimab, a further therapeutic option for non-operable or metastatic tumors has been available since June 2021.The most important preventive measure is consistent textile or chemical UV protection in already affected individuals. In addition, nicotinamide and celecoxib can be used orally for prevention. For follow-up, the current S2k guideline recommends regular self-monitoring and standardized medical check-ups.

Multi-parametric MRI for radiotherapy simulation

Magnetic resonance imaging (MRI) has become an important imaging modality in the field of radiotherapy (RT) in the past decade, especially with the development of various novel MRI and image-guidance techniques. In this review article, we will describe recent developments and discuss the applications of multi-parametric MRI (mpMRI) in RT simulation. In this review, mpMRI refers to a general and loose definition which includes various multi-contrast MRI techniques. Specifically, we will focus on the implementation, challenges, and future directions of mpMRI techniques for RT simulation.

Identifying core components of a radiotherapy comfort intervention package using nominal group technique

INTRODUCTION

A comfortable treatment position in radiotherapy may promote patient stability and improve outcomes such as accuracy. The aim of this study was to identify, prioritise and determine the feasibility of delivery of intervention components as part of a radiotherapy comfort intervention package.

METHODS

Prior research, consisting of a systematic review and qualitative interviews with patient and therapeutic radiographers, was triangulated and 15 intervention components developed. An online nominal group technique consensus meeting with 7 patients who received radiotherapy exceeding 10 min for one of three anatomical cancer sites and 3 therapeutic radiographers (TRs) participated. Four activities were undertaken: 1) discussion of comfort intervention components; 2) initial vote; 3) prioritisation of intervention components; and 4) discussion of feasibility in radiotherapy and were analysed using established quantitative and qualitative methods.

RESULTS

One intervention component was added from initial discussions to the 15 pre-determined components being discussed. 11 components were recommended as 'accepted' (n = 5) or 'accepted with caution' (n = 6) to proceed to development. The highest scoring intervention components were 'Compassionate & empathetic communication training for TRs' and 'Tailored information, e.g., TRs provide the required information only as part of preparation for treatment'. Anther that followed closely was 'Adjustments & supports provided for arms or legs during treatment by TRs'. Those 'accepted with caution' included 'Soft pads/mattress under the body to alleviate body discomfort managed by TRs'. Qualitative analysis highlighted concerns over the radiation environment and emphasised the importance of resources such as equipment, training, and time.

CONCLUSION

The recommended comfort interventions have potential to improve patient comfort during radiotherapy and should be considered to incorporate into positioning and immobilisation guidelines. However, specific intervention strategies to address these components will need to be developed and robustly evaluated.

IMPLICATIONS FOR PRACTICE

Comfort interventions might help patients relax and stay still during treatment, which could improve treatment accuracy and efficacy. Introducing these comfort interventions in practice have potential to lead to a more positive patient experience and improved overall quality of care during radiotherapy.

Mitochondrial metabolism: a predictive biomarker of radiotherapy efficacy and toxicity

INTRODUCTION

Radiotherapy is a mainstay of cancer treatment. Clinical studies revealed a heterogenous response to radiotherapy, from a complete response to even disease progression. To that end, finding the relative prognostic factors of disease outcomes and predictive factors of treatment efficacy and toxicity is essential. It has been demonstrated that radiation response depends on DNA damage response, cell cycle phase, oxygen concentration, and growth rate. Emerging evidence suggests that altered mitochondrial metabolism is associated with radioresistance.

METHODS

This article provides a comprehensive evaluation of the role of mitochondria in radiotherapy efficacy and toxicity. In addition, it demonstrates how mitochondria might be involved in the famous 6Rs of radiobiology.

RESULTS

In terms of this idea, decreasing the mitochondrial metabolism of cancer cells may increase radiation response, and enhancing the mitochondrial metabolism of normal cells may reduce radiation toxicity. Enhancing the normal cells (including immune cells) mitochondrial metabolism can potentially improve the tumor response by enhancing immune reactivation. Future studies are invited to examine the impacts of mitochondrial metabolism on radiation efficacy and toxicity. Improving radiotherapy response with diminishing cancer cells' mitochondrial metabolism, and reducing radiotherapy toxicity with enhancing normal cells' mitochondrial metabolism.

Problems Affecting Accurate Dose Measurement in Small-Field for Linear Accelerator

BACKGROUND

The use of relatively narrow fields has become necessary with the advent of intricate and accurate radiation therapy delivery dose to patients; therefore, small-field dosimetry faces several difficulties. Both dose calculations and measurements require to be performed with extra care, due to the uncertainty that might be increased by using such small field sizes.

MATERIAL AND METHODS

In this study, we investigated the effect of detectors size on the dosimetry of small fields [starting with radiation fields from (1cm x 1cm), (2cm x 1cm), and (3cm x 1cm)...etc., up to (4cm x 5cm) and (5cm x 5cm)]. We used the linear accelerator and different types of ionization chambers i.e. [Farmer FC65-P, CC13, and CC01 (pinpoint)] an addition to semiconductors i.e. (IBA Razor diode)], and we investigated all detectors to read the absorbed dose in water under the reference conditions (field 10cm x10cm, SSD 100cm and depth 10cm).

RESULTS

While measuring the absolute dose under reference conditions, all detectors had a non-significant difference of less than ±2%, except for the Razor diode, which showed a significant difference of ± 5%. On the other hand, when small fields were measured, we discovered a significant difference of 48%, compared to the Razor diode.

CONCLUSION

The Razor diode is more stable in small-field dosimetry than other detectors. Also, the Razor Diode is intended for relative dosimetry but, it shall not be used for absolute dose measurements.

A solitary osteolytic lesion with pathological fracture in the cervical spine - a case report

BACKGROUND

Langerhans cell histiocytosis (LCH) is a rare disorder. The treatment options vary depending on how many organs are involved and how extensive the disease is. In this report, a case of LCH with isolated 6th cervical vertebra (C6) collapse was presented. This case was treated with anterior corpectomy and instrumented fusion, followed by local radiotherapy (RT), with a good clinical outcome up to postoperative six months.

CASE PRESENTATION

This was a 47-year-old female patient with a complaint of neck pain and bilateral shoulder pain for two months before consultation. She was initially treated with analgesics, but the pain was persistent. Further radiological evaluations revealed an osteolytic lesion within the C6 vertebral body with a pathological fracture. Magnetic resonance imaging (MRI) with contrast of the cervical spine revealed diffused hypointense signal changes on the T1-weighted images and hyperintense signal changes on the T2-weighted images in the C6 vertebral body, with significant contrast-enhanced infiltration signals. Furthermore, in positron emission tomography-computed tomography (PET-CT), focal hypermetabolism and abnormal uptake signals were seen only in the C6 vertebral body. The patient underwent an anterior cervical corpectomy with instrumented fusion. The histopathological results confirmed the diagnosis of LCH. The patient reported significant pain relief on postoperative day one. Moreover, she was treated by local RT at postoperative one month. Good clinical outcomes were achieved in the form of no pain and recovery in neck mobility up to postoperative six months. No evidence of recurrence was observed at the final follow-up.

CONCLUSIONS

This case report describes a treatment option for a solitary C6 collapse with LCH managed by anterior corpectomy and instrumented fusion, followed by local RT, with a good clinical outcome at postoperative six months. More studies are needed to elucidate whether such a treatment strategy is superior to surgery or RT alone.

Fifteen-Year Outcomes after Monitoring, Surgery, or Radiotherapy for Prostate Cancer

BACKGROUND

Between 1999 and 2009 in the United Kingdom, 82,429 men between 50 and 69 years of age received a prostate-specific antigen (PSA) test. Localized prostate cancer was diagnosed in 2664 men. Of these men, 1643 were enrolled in a trial to evaluate the effectiveness of treatments, with 545 randomly assigned to receive active monitoring, 553 to undergo prostatectomy, and 545 to undergo radiotherapy.

METHODS

At a median follow-up of 15 years (range, 11 to 21), we compared the results in this population with respect to death from prostate cancer (the primary outcome) and death from any cause, metastases, disease progression, and initiation of long-term androgen-deprivation therapy (secondary outcomes).

RESULTS

Follow-up was complete for 1610 patients (98%). A risk-stratification analysis showed that more than one third of the men had intermediate or high-risk disease at diagnosis. Death from prostate cancer occurred in 45 men (2.7%): 17 (3.1%) in the active-monitoring group, 12 (2.2%) in the prostatectomy group, and 16 (2.9%) in the radiotherapy group (P = 0.53 for the overall comparison). Death from any cause occurred in 356 men (21.7%), with similar numbers in all three groups. Metastases developed in 51 men (9.4%) in the active-monitoring group, in 26 (4.7%) in the prostatectomy group, and in 27 (5.0%) in the radiotherapy group. Long-term androgen-deprivation therapy was initiated in 69 men (12.7%), 40 (7.2%), and 42 (7.7%), respectively; clinical progression occurred in 141 men (25.9%), 58 (10.5%), and 60 (11.0%), respectively. In the active-monitoring group, 133 men (24.4%) were alive without any prostate cancer treatment at the end of follow-up. No differential effects on cancer-specific mortality were noted in relation to the baseline PSA level, tumor stage or grade, or risk-stratification score. No treatment complications were reported after the 10-year analysis.

CONCLUSIONS

After 15 years of follow-up, prostate cancer-specific mortality was low regardless of the treatment assigned. Thus, the choice of therapy involves weighing trade-offs between benefits and harms associated with treatments for localized prostate cancer. (Funded by the National Institute for Health and Care Research; ProtecT Current Controlled Trials number, ISRCTN20141297; ClinicalTrials.gov number, NCT02044172.).

Palliative radiotherapy for children: Symptom response and treatment-associated toxicity according to radiation therapy dose and fractionation

BACKGROUND/OBJECTIVES

Radiotherapy is an effective palliative treatment in advanced cancer. Shorter palliative treatment courses are recommended for adults, though pediatric data addressing treatment efficacy and toxicity according to radiation therapy (RT) dose and fractionation are limited.

DESIGN/METHODS

Total 213 patients aged 21 years or younger receiving 422 palliative radiotherapy treatment courses from 2003 to 2016 were included. Symptom response and treatment-associated toxicity were recorded and analyzed in relationship to demographic and treatment variables.

RESULTS

Common diagnoses included sarcoma (32.5%), neuroblastoma (24.9%), leukemia/lymphoma (14.9%), and central nervous system tumors (10.9%). The most common indication for treatment was pain (46.7%). Patients received a median of 10 fractions, 2.5 Gy dose per fraction, and 21 Gy total dose. Number of RT fractions was five or less in 166 (39.3%), six to 10 fractions in 117 (27.2%), and 10 or more fractions in 139 (32.9%) of courses. Complete or partial pain relief was achieved in 85% (151 of 178 evaluable patients), including 77.8% receiving five or less fractions and 89.6% receiving more than five fractions. Highest toxicity was grade 1 in 159 (38.9%), grade 2 in 26 (6.4%), and grade 3 in two (0.5%) treatments. On multivariable analysis, RT delivered 30 or more days from death (OR 12.13, 95% CI: 2.13-69.2, p = .005) and no adjuvant chemotherapy (OR 0.14, 95% CI: 0.03-0.54, p = .005) were significantly associated with pain response, and five or less fractions were significantly associated with lower toxicity (OR 0.24, 95% CI: 0.06-0.97, p = .045).

CONCLUSIONS

Palliative RT courses of five or less fractions result in high rates of pain control and are associated with low toxicity in pediatric patients with cancer.

Estimating the skin dose near to the applicator and acute toxicity in breast cancer patients: An intraoperative electron radiotherapy technique

Introduction

Intraoperative electron radiation therapy (IOERT) is one of the most recently popular therapeutic methods for breast cancer. This study aimed to measure the skin dose near the applicator during IOERT of breast cancer patients, as well as, the incidence of acute toxicity after surgery.

Materials and Methods

Thirty-six female patients participated in the current study with the prescribed dose of 21 and 12 Gy for IOERT as full and boost, respectively. The skin dose was investigated based on different applicator sizes, tumor bed thicknesses, and monitor units (MUs). The energy was chosen 8 MeV, and EBT3 film was used for the dosimetric process. In addition, the acute toxicity included healing time for the surgical wound, scaling of the skin, itching, necrosis, redness as well as seroma formation for 1 week and 1 month were recorded. The results were compared to those of 22 patients who underwent the surgery without IOERT.

Results

The highest skin dose for the patients was obtained 2.09 Gy, which is lower than the threshold dose (6 Gy). Furthermore, the findings showed that the average skin dose was higher in bigger applicator sizes and MU and lower tumor bed thicknesses. The average of wound healing for the patient underwent IOERT and without the use of IOERT (as the control group) was 19.32 and 11.67 days, respectively. One month after surgery, the volume of aspirated seroma was higher in the patients who performed IOERT compared to the control group (250 ml vs. 200 ml). It is notable that there were not observed any redness, itching, scaling, and necrosis in both investigated groups.

Conclusion

Owing to the results, the skin dose during IOERT was lower than the recommended level. The dose of IOERT as a full was higher than boost which can be related to the lower number of the patients in full method; however, there was a well-tolerated without severe acute complication, especially seroma formation and wound healing time in both full and boost methods.

Status of cancer treatment by radiotherapy and requirement of radiation oncology medical physicists in Asia Oceania federation of organizations for medical physics region

Objective

Cancer is a major health problem worldwide including Asian-Pacific region. The region hosts over 4.5 billion people, over 60% of the world population and very divergent socioeconomically. The major cancers in the region in male include lung, stomach, liver, colorectal and esophagus and in female breast, lung, cervix, colorectal, and stomach. Over 60% of cancer patients need radiotherapy alone or in combination with surgery and/or chemotherapy, and therefore, radiotherapy is the main and essential modality of cancer treatment. Radiation oncology medical physicists play a pivotal role in efficient implementation of radiotherapy. This study was aimed to assess the status of cancer treatment by radiotherapy and the requirement of radiation oncology medical physicists in the region.

Materials and Methods

To access the status and requirement of radiotherapy machines, availability of radiation oncology physicists in the region of Asia Oceania Federation of Organizations for Medical Physics (AFOMP), we have carried out a survey by sending questioners to AFOMP National Medical Physics Organizations (NMO). We received response from 21 countries, 100% response, regarding availability of teletherapy units, number of medical physicists working in radiotherapy and related information. Using GLOBOCAN cancer incidence data and considering 62.5% of cancer patients need radiotherapy treatment and up to 500 cancer patients can be treated in a year on one teletherapy machine, the gap between the available and required teletherapy machine to treat all the cancer patients requiring radiotherapy is estimated. Further, we estimated the gap between radiotherapy medical physicists available and required as per International Atomic Energy Agency and European Society for Therapeutic Radiology and Oncology guidelines.

Results

It was observed that availability of teletherapy machines in AFOMP region is 0.21-14.0 teletherapy machine/million population and radiotherapy medical physicist are 0.82-2.43/teletherapy unit.

Late effects and frontline treatment selection for children with non-Hodgkin lymphoma

Approximately 1 in 640 adults between 20 and 40 years of age is a survivor of childhood cancer. However, survival has often come at the expense of increased risk of long-term complications, including chronic health conditions and higher mortality rates. Similarly, long-term survivors of childhood non-Hodgkin lymphoma (NHL) experience significant morbidity and mortality related to prior cancer treatments, highlighting the importance of primary and secondary prevention strategies to mitigate late toxicity. As a result, effective treatment regimens for pediatric NHL have evolved to reduce both short- and long-term toxicity through cumulative dose reductions and elimination of radiation. The establishment of effective regimens facilitates shared decision-making opportunities for frontline treatment selection that considers efficacy, acute toxicity, convenience, and late effects of treatments. The current review seeks to merge current frontline treatment regimens with survivorship guidelines to enhance understanding of potential long-term health risks to facilitate best treatment practices.

Characteristics of a real-time radiation exposure dosimetry system using a synthetic ruby for radiotherapy

Radiotherapy-related medical accidents are frequently caused by planning problems, excessive irradiation during radiotherapy, or patient movement. This is partly because the local exposure dose cannot be directly monitored during radiotherapy. This article discusses the development of our recent real-time radiation exposure dosimetry system that uses a synthetic ruby for radiation therapy. Background noise was observed before the measurement of the short-term characteristic features. Regarding the relationship between the number of photons and dose rate, using 100 monitor units (MU)/min as the measurement value, the counts decreased by approximately 10% at 600 MU/min. A clear correlation was observed between the MU value and the number of photons (R² = 0.9987). The coefficient of variation (%CV) was less than ± 1.0% under all the irradiation conditions. Slight differences were observed between the ion chamber and the synthetic ruby dosimeters in the measurement of the percentage depth dose. However, this difference was almost matched by correcting for the Cherenkov light. Although some problems were observed with the synthetic ruby dosimeter system, our results indicate that the developed dosimeter can be used to measure the irradiation dose of patients in real time, with no significant impact on the data, as any effect would be masked by the larger effect of the ruby; however, the impact requires a detailed assessment in the future.

An Update to the Malthus Model for Radiotherapy Utilisation in England

AIMS

The Malthus Programme predicts national and local radiotherapy demand by combining cancer incidence data with decision trees detailing the indications, and appropriate dose fractionation, for radiotherapy. Since the last model update in 2017, technological advancements and the COVID-19 pandemic have led to increasing hypofractionation of radiotherapy schedules. Indications for radiotherapy have also evolved, particularly in the context of oligometastatic disease. Here we present a brief update on the model for 2021. We have updated the decision trees for breast, prostate, lung and head and neck cancers, and incorporated recent cancer incidence data into our model, generating a current estimate of fraction demand for these four cancer sites across England.

MATERIALS AND METHODS

The decision tree update was based on evidence from practice-changing randomised controlled trials, published guidelines, audit data and expert opinion. Site- and stage-specific incidence data were taken from the National Disease Registration Service. We used the updated model to estimate the proportion of patients who would receive radiotherapy (appropriate rate of radiotherapy) and the fraction demand per million population at a national and Clinical Commissioning Group level in 2021.

RESULTS

The total predicted fraction demand has decreased by 11.4% across all four cancer sites in our new model, compared with the 2017 version. This reduction can be explained primarily by greater use of hypofractionated treatments (including stereotactic ablative radiotherapy) and a shift towards earlier stage presentation. The only large change in appropriate rate of radiotherapy was an absolute decrease of 3% for lung cancer.

CONCLUSIONS

Compared with our previous model, the current version predicts a reduction in fraction demand across England. This is driven principally by hypofractionation of radiotherapy regimens, using technology that requires increasingly complex planning. Treatment complexity and local service factors need to be taken into account when translating fraction burden into linear accelerator demand or throughput.

From Basic Radiobiology to Translational Radiotherapy

The Special Issue, entitled "From basic radiobiology to translational radiotherapy", highlights recent advances in basic radiobiology and the potential to improve radiotherapy in translational research [...].

Dosimetric characterization of a mobile accelerator dedicated for intraoperative radiation therapy: Monte Carlo simulations and experimental validation

PURPOSE

This Technical Note validates previously published data about the dosimetry of the electron beams produced by a mobile accelerator dedicated for intraoperative radiation therapy (IORT). The evaluation of the directional response of a PTW microDiamond detector is presented together with a detailed analysis of the output factors (OFs) for bevelled applicators.

METHODS

The OFs of the 6, 8, 10 and 12 MeV electron beams produced by a light intraoperative accelerator (LIAC, SIT, Italy) were measured in a commercial water phantom using the microDiamond. A set of flat and bevelled applicators with sizes ranging from 4 to 10 cm was characterized. For bevelled applicators, a correction for the angular dependence of the microDiamond was calculated using a home-made spherical phantom. Correction factors were obtained through measurements performed rotating the accelerator treatment head at 0°, 15°, 30° and 45°.

RESULTS

For flat applicators, the average deviation between measured and simulated OFs was (-1.1 ± 0.7)%. The microDiamond showed a higher angular dependence for the 6 MeV beam (∼8% for angles up to 45°, range 92 % ÷ 100 %), while the variations for 8, 10 and 12 MeV beams were ∼ 4 % (range 97 % ÷ 101 %). Correcting for this dependence, the average deviation of the OFs for bevelled applicators was (-0.9 ± 1.6)%.

CONCLUSIONS

The presented results were in very good agreement with those reported in literature. Very similar deviations were found between flat and bevelled applicators confirming the suitability of our method to determine the angular dependence correction factors of the microDiamond detector.

The Effect of Intensity-Modulated Radiotherapy to the Head and Neck Region on the Oral Innate Immune Response and Oral Microbiome: A Prospective Cohort Study of Head and Neck Tumour Patients

Neutrophils, also known as polymorphonuclear leukocytes (PMNs), form a significant component of the innate host response, and the consequence of the interaction between the oral microbiota and PMNs is a crucial determinant of oral health status. The impact of radiation therapy (RT) for head and neck tumour (HNT) treatment on the oral innate immune system, neutrophils in particular, and the oral microbiome has not been thoroughly investigated. Therefore, the objective of this study was to characterize RT-mediated changes in oral neutrophils (oPMNs) and the oral microbiome in patients undergoing RT to treat HNTs. Oral rinse samples were collected prior to, during and post-RT from HNT patients receiving RT at Dental Oncology at Princess Margaret Cancer Centre. The oPMNs counts and activation states were analysed using flow cytometry, and the oral microbiome was analysed using 16S rRNA gene sequencing. Statistically significant (p < 0.05) drops in oPMN counts and the activation states of the CD11b, CD16, CD18, CD64 and H3Cit markers from pre-RT to post-RT were observed. Moreover, exposure to RT caused a significant reduction in the relative abundance of commensal Gram-negative bacteria and increased the commensal Gram-positive microbes. Ionizing radiation for the treatment of HNTs simultaneously decreased the recruitment of oPMNs into the oral cavity and suppressed their activation state. The oral microbiome composition post-RT was altered significantly due to RT which may favour the colonization of specific microbial communities unfavourable for the long-term development of a balanced oral microbiome.