Technological Advances In Radiotherapy Research Articles

Dosimetric Planning Tradeoffs to Reduce Heart Dose Using Machine Learning-Guided Decision Support Software in Patients with Lung Cancer

Cardiac toxicity is a well-recognized risk after radiation therapy (RT) in patients with non-small cell lung cancer (NSCLC). However, the extent to which treatment planning optimization can reduce mean heart dose (MHD) without untoward increases in lung dose is unknown. Retrospective analysis of RT plans from 353 consecutive patients with locally advanced NSCLC treated with intensity modulated RT (IMRT) or 3-dimensional conformal RT. Commercially available machine learning-guided clinical decision support software was used to match RT plans. A leave-one-out predictive model was used to examine lung dosimetric tradeoffs necessary to achieve a MHD reduction. Of all 232 patients, 91 patients (39%) had RT plan matches showing potential MHD reductions of >4 to 8 Gy without violating the upper limit of lung dose constraints (lung volume [V] receiving 20 Gy (V20 Gy) <37%, V5 Gy <70%, and mean lung dose [MLD] <20 Gy). When switching to IMRT, 75 of 103 patients (72.8%) had plan matches demonstrating improved MHD (average 2.0 Gy reduction, P < .0001) without violating lung constraints. Examining specific lung dose tradeoffs, a mean ≥3.7 Gy MHD reduction was achieved with corresponding absolute increases in lung V20 Gy, V5 Gy, and MLD of 3.3%, 5.0%, and 1.0 Gy, respectively. Nearly 40% of RT plans overall, and 73% when switched to IMRT, were predicted to have reductions in MHD >4 Gy with potentially clinically acceptable tradeoffs in lung dose. These observations demonstrate that decision support software for optimizing heart-lung dosimetric tradeoffs is feasible and may identify patients who might benefit most from more advanced RT technologies.

Clinical Prognostic Factors for Patients With Esophageal Cancer Treated With Definitive Chemoradiotherapy.

BackgroundTreatment with definitive chemoradiotherapy (CRT) is the best option for patients with locally advanced esophageal tumors considered unresectable or for patients without clinical conditions to undergo surgical treatment. Technological advances in radiotherapy in the last decades have made treatment more accurate with less toxicity, and the association with more effective systemic treatment has been gradually improving survival rates.AimEvaluate clinical prognostic factors for progression-free survival (PFS) and overall survival (OS) in patients with esophageal cancer treated with definitive radiotherapy (RT) and chemotherapy (ChT).Material and methodsThe clinical records of 60 patients treated from April 2011 until December 2019 with esophageal cancer considered unresectable and/or without clinical conditions for surgery, treated with definitive CRT, were analyzed. All patients had upper digestive endoscopy (UDE) with positive biopsy, neck, chest, and abdominal CT scan, and 18F-fluorodeoxyglucose positron-emission tomography (PET-CT). Patients were followed with physical examination and CTs every three months in the first and second years and every six months from the third year of follow-up. UDE was made every three to six months after the end of the treatment or in suspicion of tumor recurrence. PET-CT was also performed in the follow-up when clinically necessary. Local and regional failure (LRF) was defined as abnormalities in the image tests within the planning target volume (PTV) and/or positive biopsy on UDE. Any other failure was defined as a distant failure (DF). PFS was defined in the record of the first tumor recurrence site and OS in the death record from the date of the start of treatment.ResultsThe median age of the patients was 66 years (range: 33 to 83 years) and 46 patients (76.7%) were male. Squamous cell carcinoma (SCC) was the most frequent histological type (85%). Most patients had tumors located in the mid-thoracic esophagus (53.3%) and stage III or IV (59.9%). All patients were treated using 3D (76.7%) or intensity-modulated radiotherapy (IMRT; 23.3%). The median total dose was 50.4Gy (41.4-50.4). All patients received platinum-based ChT concomitant with RT. The most common regimen used was carboplatin and paclitaxel, with a median of five cycles. With a median follow-up of 19 months, the median PFS and OS were 10 and 20 months, respectively. LRF and DF as the first site of failure were observed in 22 (36.6%) and 26 (43.3%) patients, respectively. In the univariate analysis, tumor length lower than 2.6 cm, gross tumor volume (GTV) volume lower than 28 cm3, clinical tumor stages T1 and T2, clinical node stage N0, clinical prognostic stage groups I and II, and complete response to treatment, were statistically significant factors for better PFS and OS. In the multivariate analysis, the presence of clinical nodal stage N0 was related to better PFS (p=0.02).ConclusionNode clinical status was the most important clinical factor for PFS. Despite all the technical progress observed in radiotherapy, treatments concomitant with platinum-based chemotherapy are associated with high levels of LRF and DF. New strategies in systemic therapy and radiotherapy are necessary for improving outcomes.

Vaginal Dilator Use to Promote Sexual Wellbeing After Radiotherapy in Gynaecological Cancer Survivors: A Prospective Observational Study

Background: Since continuing advances in radiotherapy technology broaden the role of radiotherapy in the treatment of gynaecologic malignancies, the use of vaginal dilators has been introduced in order to mitigate the risk of vaginal stenosis. The main aims of this study were to investigate the vaginal dilator use efficacy in the treatment of radiation-induced vaginal stenosis and the vaginal dilator effect on sexual quality of life. Methods: We studied fifty-three patients with endometrial or cervical cancer. The participants were treated with radical or adjuvant external beam radiotherapy and/or brachytherapy. They were routinely examined at four time points post-radiotherapy when also they were asked to fill in a validated sexual function-vaginal changes questionnaire. A p-value less than 0.05 was considered statistically significant. Results: The vaginal stenosis grading score was decreased and the size of the vaginal dilator comfortably insertable was gradually increased throughout the year of vaginal dilator use while radiation-induced vaginal and sexual symptoms were improved throughout the year of VD use. All patients with initial grade 3 showed vaginal stenosis of grade 2 after 12 months of vaginal dilator use and 65.8% of the patients with grade 2 initial vaginal stenosis demonstrated final vaginal stenosis grade 1 while 77.8% of the participants with initial 1st size of vaginal dilators reached the 3rd vaginal dilator size after 12 months. Starting time of dilator therapy &lt;= 3 months after the end of radiotherapy was associated with a significant decrease in vaginal stenosis. Additionally, there was an overall upward trend regarding patients’ satisfaction with their sexual life. Conclusion: Endometrial and cervical cancer survivors should be encouraged to use vaginal dilators for the treatment of vaginal stenosis and sexual rehabilitation after radiotherapy.

Role of MRI-Based Functional Imaging in Improving the Therapeutic Index of Radiotherapy in Cancer Treatment.

Advances in radiation technology, such as intensity-modulated radiation therapy (IMRT), have largely enabled a biological dose escalation of the target volume (TV) and reduce the dose to adjacent tissues or organs at risk (OARs). However, the risk of radiation-induced injury increases as more radiation dose utilized during radiation therapy (RT), which predominantly limits further increases in TV dose distribution and reduces the local control rate. Thus, the accurate target delineation is crucial. Recently, technological improvements for precise target delineation have obtained more attention in the field of RT. The addition of functional imaging to RT can provide a more accurate anatomy of the tumor and normal tissues (such as location and size), along with biological information that aids to optimize the therapeutic index (TI) of RT. In this review, we discuss the application of some common MRI-based functional imaging techniques in clinical practice. In addition, we summarize the main challenges and prospects of these imaging technologies, expecting more inspiring developments and more productive research paths in the near future.

Radiotherapy role in non-seminomatous germ cell tumors, radiobiological and technical issues of an unexplored scenario.

Historically, non-seminomatous germ cell tumor (NSGCT) has been considered a radio-resistant disease, excluding radiotherapy (RT) from curative strategies. However, case series exploring the use of radiation treatment in this setting are often outdated, and prospective ongoing studies testing new radiotherapeutic approaches in NSGCT are lacking. Considering that tremendous advances in radiotherapy technology have enabled improved precision in RT delivery as well as dose escalation while decreasing treatment-related morbidity, we overviewed the currently available literature to explore the radiobiological basis, the technical issues, and potential strategies for implementation of RT in the management of this clinical entity. The purpose of the present overview is to provide insight for future research in this unexplored scenario. In summary, the biological rationale for RT use and potential implementation with systemic therapies exist, especially considering the advantage of new technologies, which were unavailable in the era of early literature reports. The NSGCT radioresistance paradigm could be based only on the fact that effective treatment schedules were simply undeliverable with older RT techniques due to toxicity issues, but the availability of actual techniques may prompt further exploration to offer treatment alternatives to these patients. Ongoing trials on this issue are lacking, but potential areas of research are platinum-refractory disease and consolidation therapy for residual masses after PST.

Imaging of the Chest After Radiotherapy and Potential Pitfalls

Radiotherapy is one of the cornerstones for the treatment of thoracic malignancies. The goal of radiotherapy is to deliver maximal dose to the tumor while minimizing damage to surrounding normal anatomical structures. Although advances in radiotherapy technology have considerably improved radiation delivery, potential adverse effects are still common. Post radiation changes to the chest may include different structures such as the lung, heart, great vessels, and esophagus. The purpose of this manuscript is to illustrate the post radiotherapy changes to these anatomical structures resulting from external beam radiotherapy, as well as discuss imaging pitfalls to prevent radiologist's interpretation errors.

Abstract PO-066: Relationship between KEAP1/NFE2L2 pathway activation and radiation resistance in oral cavity cancer

Abstract Radiotherapy (RT) is one of the primary treatment modalities for head and neck squamous cell carcinoma (HNSCC) either in the definitive or the adjuvant setting. Unfortunately, despite therapeutic and technological advances in radiotherapy, some patients will have persistence tumor or develop locoregional failure, resulting in significant morbidity and mortality. Presently, there is no biomarker that can reliably identify HNSCC that is resistant to RT. Recent genomic sequencing studies show that mutations in the KEAP1/NFE2L2 pathway exist in HNSCC. However, very little data is available with regards to the relationship between RT resistance and activating mutation or pathway hyperactivation of this pathway in HNSCC. Moreover, the mechanism by which dysregulation of this pathway can lead to RT resistance in HNSCC is poorly understood. Therefore, the project is aimed to study the relationship between KEAP1/NFE2L2 mutations and patient outcomes in HNSCC. To address this aim, DNA sequencing strategies and tissue microarray (TMA) are used to identify mutations and/or a hyperactivation protein signature of the KEAP1/NFE2L2 oxidative stress pathway in an oral cavity cancer patient cohorts (N = 69[MOU1]) treated with surgery and adjuvant RT. In addition, identified mutations are introduced into HNSCC cell lines and mouse xenografts to study the effect of these mutations on radiation response and to identify the mechanism by which they mediate radiation resistance. Here we find that 6% of oral cavity cancer patients harbor mutation in this pathway, primarily in a hotspot in the NFE2L2 gene. NFE2L2 mutation is associated with 100% in-field recurrence after radiotherapy. Strong co-expression of two downstream targets of this pathway (HO1 and NQO1) in tumor cells on the TMA strongly correlates with NFE2L2 mutation and in-field recurrence after RT. Finally, overexpression of the mutated NFE2L2 gene in HNC cell lines lead to increased ROS and radioresistance. Our findings suggest oral cavity cancers harboring activating mutation or a hyperactivation protein signature of the KEAP1/NFE2L2 pathway are more radioresistant. Work is ongoing to validate these findings in other types of HNSCC and to determine how to enhance radiation effectiveness in mutated tumors. Citation Format: Li Guan, Hongbin Cao, Angela Hui, Shirley Kwok, Vignesh Viswanathan, Dhanya Nambiar, Rie V. Eyben, Brittany Holmes, Christina Kong, Maximilian Diehn, Quynh-Thu Le. Relationship between KEAP1/NFE2L2 pathway activation and radiation resistance in oral cavity cancer [abstract]. In: Proceedings of the AACR Virtual Special Conference on Radiation Science and Medicine; 2021 Mar 2-3. Philadelphia (PA): AACR; Clin Cancer Res 2021;27(8_Suppl):Abstract nr PO-066.

Advances in radiotherapy technology for pediatric cancer patients and roles of medical physicists: COG and SIOP Europe perspectives.

Over the last two decades, rapid technological advances have dramatically changed radiation delivery to children with cancer, enabling improved normal-tissue sparing. This article describes recent advances in photon and proton therapy technologies, image-guided patient positioning, motion management, and adaptive therapy that are relevant to pediatric cancer patients. For medical physicists who are at the forefront of realizing the promise of technology, challenges remain with respect to ensuring patient safety as new technologies are implemented with increasing treatment complexity. The contributions of medical physicists to meeting these challenges in daily practice, in the conduct of clinical trials, and in pediatric oncology cooperative groups are highlighted. Representing the perspective of the physics committees of the Children's Oncology Group (COG) and the European Society for Paediatric Oncology (SIOP Europe), this paper provides recommendations regarding the safe delivery of pediatric radiotherapy. Emerging innovations are highlighted to encourage pediatric applications with a view to maximizing the therapeutic ratio.

Thoracic radiotherapy in small cell lung cancer-a narrative review.

Small-cell lung cancer (SCLC) represents 10–15% of all lung cancers and has a poor prognosis. Thoracic radiotherapy plays a central role in current SCLC management. Concurrent chemoradiotherapy (CTRT) is the standard of care for localised disease (stage I−III, limited-stage, LS). Definitive thoracic radiotherapy may be offered in metastatic patients (stage IV, extensive stage, ES-SCLC) after chemotherapy. For LS-SCLC, the gold standard is early accelerated hyperfractionated twice-daily CTRT (4 cycles of cisplatin etoposide, starting with the first or second chemotherapy cycle). Modern radiation techniques should be used with involved-field radiotherapy based on baseline CT and PET/CT scans. In ES-SCLC, thoracic radiotherapy should be discussed in cases of initial bulky mediastinal disease/residual thoracic disease not progressing after induction chemotherapy. This strategy was however not assessed in recent trials establishing chemo-immunotherapy as the standard first line treatment in ES-SCLC. Future developments include technical radiotherapy advances and the incorporation of new drugs. Thoracic irradiation is delivered more precisely given technical developments (IMRT, image-guided radiotherapy, stereotactic radiotherapy), reducing the risks of severe adverse events. Stereotactic ablative radiotherapy may be discussed in rare early stage (T1 to 2, N0) inoperable patients. A number of current clinical trials are investigating immunoradiotherapy. In this review, we highlight the current role of thoracic radiotherapy and describe ongoing research in the integration of biological surrogate markers, advanced radiotherapy technologies and novel drugs in SCLC patients.

MR-Guided Radiotherapy for Rectal Cancer: Current Perspective on Organ Preservation.

Online MRI-guided radiotherapy (MRgRT) is one of the most recent technological advances in radiotherapy. MRgRT permits the visualization of tumorous and healthy tissue while the patient is on the treatment table and online daily plan adaptations following the observed anatomical changes. In the context of rectal cancer, online MRgRT is a very promising modality due to the pronounced geographical variability of tumor tissues and the surrounding healthy tissues. This current paper will discuss the possible applications of online MRgRT, in particular, in terms of radiotherapy dose escalation and response prediction in organ preservation approaches for rectal cancer.

Radiation: A New Multi-Disciplinary Open Access Journal for Advances in Radiation Technology

Radiation is a perpetual part of our daily life [...]

Normal Tissue Injury Induced by Photon and Proton Therapies: Gaps and Opportunities.

Despite technological advances in radiation therapy (RT) and cancer treatment, patients still experience adverse effects. Proton therapy (PT) has emerged as a valuable RT modality that can improve treatment outcomes. Normal tissue injury is an important determinant of the outcome; therefore, for this review, we analyzed 2 databases: (1) clinical trials registered with ClinicalTrials.gov and (2) the literature on PT in PubMed, which shows a steady increase in the number of publications. Most studies in PT registered with ClinicalTrials.gov with results available are nonrandomized early phase studies with a relatively small number of patients enrolled. From the larger database of nonrandomized trials, we listed adverse events in specific organs/sites among patients with cancer who are treated with photons and protons to identify critical issues. The present data demonstrate dosimetric advantages of PT with favorable toxicity profiles and form the basis for comparative randomized prospective trials. A comparative analysis of 3 recently completed randomized trials for normal tissue toxicities suggests that for early stage non-small cell lung cancer, no meaningful comparison could be made between stereotactic body RT and stereotactic body PT due to low accrual (NCT01511081). In addition, for locally advanced non-small cell lung cancer, a comparison of intensity modulated RTwith passive scattering PT (now largely replaced by spot-scanned intensity modulated PT), PT did not provide any benefit in normal tissue toxicity or locoregional failure over photon therapy. Finally, for locally advanced esophageal cancer, proton beam therapy provided a lower total toxicity burden but did not improve progression-free survival and quality of life (NCT01512589). The purpose of this review is to inform the limitations of current trials looking at protons and photons, considering that advances in technology, physics, and biology are a continuum, and to advocate for future trials geared toward accurate precision RT that need to be viewed as an iterative process in a defined path toward delivering optimal radiation treatment. A foundational understanding of the radiobiologic differences between protons and photons in tumor and normal tissue responses is fundamental to, and necessary for, determining the suitability of a given type of biologically optimized RT to a patient or cohort.

Recent Advances and Future Directions in Clinical Management of Head and Neck Squamous Cell Carcinoma.

Simple SummaryEven with recent advances, there are urgent needs for novel therapies to improve overall survival and decrease toxicities in the management of head and neck squamous cell carcinoma (HNSCC). This article reviews historical data to provide a context and highlights recent data in understanding of epidemiology and pathophysiology and supporting changes in treatments of HNSCC, particularly in patients with recurrent and/or metastatic disease. For use of immune checkpoint modulators such as programmed cell death protein 1 (PD-1) inhibitors, potential predictive biomarkers of clinical benefits are also summarized. In addition, this article reviews currently ongoing clinical trials and provides a perspective on future research directions.Head and neck squamous cell carcinoma (HNSCC) is the most common cancer arising in the head and neck region. The most common risk factors are smoking, excessive drinking, and human papillomavirus (HPV) infection. While the overall incidence of smoking is decreasing, the incidence of HPV-related HNSCC is increasing in the United States and Western Europe, which led to a shift in understanding of the pathophysiology, treatment, and prognosis of this disease. The outcomes for non-metastatic HNSCC remains very encouraging and continues to improve. Advances in radiation technology and techniques, better organ preserving surgical options, and multidisciplinary treatment modalities have improved cure rates for locally advanced HNSCC patients. The treatment of metastatic disease, however, remains an area of need. The advancement of immune checkpoint inhibitors has provided significantly better outcomes, but only a small proportion of patients obtain benefits. Most recurrent and/or metastatic HNSCC patients continue to have poor survival. This has led to the vigorous investigation of new biomarkers and biomarker-based therapies. Novel therapeutic options including adaptive cellular therapy and therapeutic vaccines are also on the horizon. In this review, we highlight the latest advances in the field of HNSCC and the future direction of research.

Radiation Hardness Test of a Silicon Detector under Radiation Dose Rate of Nuclear Power Plant for In-Containment Coolant Leakage Detection System

An influence evaluation by background radiation on a silicon detector, which will be used to detect a coolant leakage, and installed in a containment building of a nuclear power plant, was performed and the result was discussed. The detector that consists of a silicon sensor and preamplifier mounted in a shielding structure which composed of a 5 cm lead cylinder will be installed in an annulus zone that is influenced by background radiation (neutron and gamma ray) from an operation of a nuclear reactor. Absorbed dose rates on a silicon sensor and preamplifier were calculated as 2.15 mGy/hr and 1.05 mGy/hr, respectively, by Monte Carlo N-Particle (MCNP) simulation. Data of background radiation had referred to a Final Safety Analysis Report (FSAR) of a nuclear power plant in the Republic of Korea. A silicon sensor and preamplifier were irradiated by a Co60 gamma radiation source equipped in a facility of Korea Atomic Energy Research Institute Advanced Radiation Technology Institute (KAERI ARTI) of the Republic of Korea. A Po-210 alpha source was used as a check source to evaluate a state of a function of the detector during gamma irradiation. Absorbed dose rates were about 22.92 mGy/hr and 6.6 mGy/hr on silicon sensor and preamplifier, respectively. Before and during gamma irradiation, a count rates from the check source wasn`t changed (from 18.4 cps to 18.4±0.2 cps after irradiation), and any degradations of function also weren`t observed. Even more harsh condition than calculated dose rates referred by the condition of background radiation of in-containment, the silicon detector maintained the ability of function of charged particles detection. Based on the result, it has been demonstrated that a silicon detector is a suitable detector for detecting charged particles from a leaked coolant even during interfered by the background radiation of a primary system of a nuclear power plant.

Management of recurrent or progressive spinal metastases: reirradiation techniques and surgical principles.

With the growing incidence of new cases and the increasing prevalence of patients living longer with spine metastasis, a methodological approach to the management of patients with recurrent or progressive disease is increasing in relevance and importance in clinical practice. As a result, disease management has evolved in these patients using advanced surgical and radiotherapy technologies. Five key goals in the management of patients with spine metastases include providing pain relief, controlling metastatic disease at the treated site, improving neurologic deficits, maintaining or improving functional status, and minimizing further mechanical instability. The focus of this review is on advanced reirradiation techniques, given that the majority of patients will be treated with upfront conventional radiotherapy and further treatment on progression is often limited by the cumulative tolerance of nearby organs at risk. This review will also discuss novel surgical approaches such as separation surgery, minimally invasive percutaneous instrumentation, and laser interstitial thermal therapy, which is increasingly being coupled with spine reirradiation to maximize outcomes in this patient population. Lastly, given the complexities of managing recurrent spinal disease, this review emphasizes the importance of multidisciplinary care from neurosurgery, radiation oncology, medical oncology, neuro-oncology, rehabilitation medicine, and palliative care.

Modeling Tumor Control Probability for Radiotherapy of Skin Cancer Based on Pooled Clinical Data

Skin cancer is the most common malignancy worldwide. Radiotherapy (RT) with either kilovoltage x-rays and/or megavoltage electron and/or photon beams are treatment options for skin cancer, particularly for non-operative candidates due to comorbidity or cosmetical concerns or patient refusal. Our objective is to model tumor control probability (TCP) for RT of primary basal or squamous cell carcinoma (BCC/ SCC) based on published clinical data in order to optimize treatment schemes. Reports citing crude estimates of local tumor control for primary BCC and SCC of the head/face by tumor size ≤ 2 cm or > 2 cm were considered in our TCP modeling based on a TCP model: TCP = 1/(1+exp(-(BED14 - BEDprolif·T - TD50)/k), where BED is the biological effective dose calculated from the report using the linear quadratic model with a/β = 14 Gy, BEDprolif is the BED recovered per day due to proliferation, T is the treatment time in days, TD50 is the dose required to achieve 50% tumor control, & k is a fitting constant related to the slope of the dose response curve at TD50. These model parameters were estimated using the Chi-squared fitting method. Sample equivalent fractionation schemes and the effect of varying treatment time on TCP were estimated. Literature search yield eight reports useful in the development of a TCP model for BCC / SCC. The reported a median total dose of 48.2 Gy (range: 35-63.1 Gy), dose per fraction of 3.6 Gy/fx (range: 2.4-7.3 Gy/fx), [BED14 = 62.0 Gy, (range: 52.5-85.5 Gy)] & total treatment time of 23.8 days (range: 10-39.0 days). Four TCP models were generated for BCC ≤ 2cm, BCC > 2cm, SCC ≤ 2 cm, and SCC > 2 cm. For BCC, the model parameters were found to be TD50 = 0 Gy, k = 14.7 Gy-1, & BEDprolif = 0.507 Gy/day & TD50 = 48.8 Gy, k = 2.744 Gy-1, & BEDprolif = 0.091 Gy/day for tumor sizes of < 2cm & > 2 cm, respectively. Model parameters for SCC were: TD50 = 0 Gy, k = 18.986 Gy-1, & BEDprolif = 0.166 Gy/day & TD50 = 54.1 Gy, k = 2.98 Gy-1, & BEDprolif = 0.060 Gy/day for tumors < 2cm & > 2 cm, respectively. Additional calculations with a fixed BED14 = 60 Gy show that increasing the treatment time from 5 to 30 days has a 1-2% reduction in TCP for tumors ≤ 2 cm, while this increased time results in an 6-7% reduction in TCP for tumors > 2 cm. The scheme of 5 x 7.2 Gy in one week is found to be equivalent to 15 x 3 Gy in 3 weeks in term of TCP. A TCP model for primary BCC / SCC was developed based on published clinical data and may be used to design new RT regimens for advanced RT technology. Prolonged treatment times could have a significant effect on control for tumors > 2 cm in size. Shortened treatment times may permit the delivery of larger fractional doses provided the normal tissue tolerance is respected.

Current status and comparison of national health insurance systems for advanced radiation technologies in Korea and Japan.

PurposeThis study aimed to compare the current status of the national health insurance system (HIS) for advanced radiation technologies in Korea and Japan.Materials and methods: The data of the two nations were compared according to the 2019 guidelines on the application and methods of medical care benefit from the Ministry of Health and Welfare of Korea and the 2020 medical fee points list set by the Ministry of Health, Labor and Welfare of Japan.ResultsBoth countries have adopted the social insurance system and the general payment system which is fee-for-service for radiotherapy. However, for proton and carbon ion therapy, the Japanese system has adopted a bundled payment system. Copayment for radiotherapy is 5% in Korea and 30% (7–69 years old) in Japan, with a ceiling system. A noticeable difference is that additional charges for hypofractionation, tele-radiotherapy planning for an emergency, tumor motion-tracking, purchase price of an isotope, and image-guided radiotherapy are allowed for reimbursement in the Japanese system. There are some differences regarding the indication, qualification standards, and facility standards for intensity-modulated radiation therapy, stereotactic body radiation therapy, and proton therapy.ConclusionPatterns of cancer incidence, use of radiotherapy and infrastructure, and national HIS are very similar between Korea and Japan. However, there are some differences in health insurance management systems for advanced radiation technologies.

Radiotherapy for Brain Tumors: Current Practice and Future Directions

Radiotherapy is an important component of the treatment for primary and metastatic brain tumors. Due to the close proximity of critical structures and normal brain parenchyma, Central Nervous System (CNS) radiotherapy is associated with adverse effects such as neurocognitive deficits, which must be weighed against the benefit of improved tumor control. Advanced radiotherapy technology may help to mitigate toxicity risks, although there is a paucity of high-level evidence to support its use. Recent advances have been made in the treatment for gliomas, meningiomas, benign tumors, and metastases, although outcomes remain poor for many high grade tumors. This review highlights recent developments in CNS radiotherapy, discusses common treatment toxicities, critically reviews advanced radiotherapy technologies, and highlights promising treatment strategies to improve clinical outcomes in the future.

Problems and Promises of Introducing the Magnetic Resonance Imaging Linear Accelerator Into Routine Care: The Case of Prostate Cancer.

The new radiotherapy high field, 1.5 Tesla MRI-guided linear accelerator (MR-Linac) is being clinically introduced. Sensing and evaluating opportunities and barriers at an early stage will facilitate its eventual scale-up. This study investigates the opportunities and barriers to the implementation of MR-Linac into prostate cancer care based on 43 semi-structured interviews with Dutch oncology care professionals, hospital and division directors, patients, payers and industry. The analysis was guided by the Non-adoption, Abandonment, Scale-up, Spread, and Sustainability framework of new medical technologies and services. Opportunities included: the acquirement of (1) advanced MRI-guided radiotherapy technology with (2) the potential for improved patient outcomes and (3) economic benefits, as well as (4) professional development and (5) a higher hospital quality profile. Barriers included: (1) technical complexities, (2) substantial staffing and structural investments, (3) the current lack of empirical evidence of clinical benefits, (4) professional silos, and (5) the presence of patient referral patterns. While our study confirms the expected technical and clinical prospects from the literature, it also reveals economic, organizational, and socio-political challenges.

Diagnosis and treatment of radiation intestinal injury: current status and perspectives

Radiation intestinal injury (RII) refers to the intestinal complication resulting from radiation therapy of pelvic, abdominal or retroperitoneal tumor, which involves the small intestine, colon and rectum. Although the advances in radiotherapy technology have decreased the injury of adjacent tissues, 90% of the patients receiving radiotherapy have acute symptoms, the quality of life is affected due to gastrointestinal symptoms in 50% of patients, and 20%-40% of patients have moderate to severe symptoms. Based on the pathological stage, characteristics and clinical manifestations, RII can be divided into acute and chronic types, generally 3 to 6 months as the cutoff in clinical history. The main preventions of RII include reducing the radiation doses and narrowing the exposure fields. Acute RII is characterized by mucosal inflammation and self-limitation, and its treatment includes symptomatic and nutritional management. As the chronic ischemia and fibrosis in chronic RII are irreversible, bowel resection is the ideal treatment. The surgical indications for chronic RII are grade 3 and 4 intestinal injuries, including obstruction, bleeding, intestinal necrosis, perforation, and fistula. The current surgical procedure is definitive intestinal resection with stage I or II gastrointestinal reconstruction. The optimal time for definitive surgery is still controversial. Based on our experiences, 1 year after the end of radiation therapy is optimal. Under the circumstances of emergency surgery, severe malnutrition, abdominal infection, extensive intestinal injury, and abdominal adhesions that cannot be mobilized, ostomy and abdominal drainage are recommended, and definitive surgery can be considered after the return to enteral nutrition and extinction of intestinal inflammation. Preoperative setting of ureteral catheter, imaging assessment of colorectal position and iliac vascular injury, and preoperative nutritional support can reduce the risk of systemic complications effectively.