A Japanese multi-institutional phase II study of moderate hypofractionated intensity-modulated radiotherapy with image-guided technique for prostate cancer.

BACKGROUND: The aim of this multi-institutional phase II study was to confirm the safety and the potential efficacy of moderately hypofractionated intensity-modulated radiotherapy (IMRT) with prostate-based image-guidance for Japanese patients. METHODS: Patients with low- or intermediate-risk localized prostate cancer were eligible. Patients with a part of high risk (having only one of the following factors, cT3a, 20 < PSA ≤ 30, or GS = 8 or 9) were also included. Hypofractionated IMRT using daily image-guided technique with prostate matching was performed with a total dose of 70 Gy in 28 fractions. Neoadjuvant hormonal therapy for 4-8 months was mandatory for patients with intermediate or high-risk prostate cancer. RESULTS: From 20 institutions, 134 patients enrolled. The median follow-up was 5.16 years (range, 1.43-6.47 years). The number of patients with low, intermediate, and high-risk prostate cancer was 20, 80, and 34, respectively. The 5-year overall, biochemical failure-free, and clinical failure-free survival was 94.5%, 96.0%, and 99.2%, respectively. The 5-year biochemical failure-free survival for patients with low-, intermediate-, and high-risk disease was 94.1%, 97.4%, and 93.9%, respectively. The incidences of grade 2 gastrointestinal (GI) and genitourinary (GU) late toxicities at 5 years were 5.3% and 5.3%, respectively. There are no acute or late toxicities ≥ grade 3. Of 124 patients who were followed for up to 5 years, the grade 2 late GU or GI toxicities were 10.5% (90% confidence intervals, 6.3-16.2%, p = 0.0958). CONCLUSION: The safety and efficacy of moderately hypofractionated IMRT with prostate-based image-guidance was confirmed among Japanese patients with prostate cancer.

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.

Lipid Polyunsaturated Fatty Acid Chains in Mouse Kidneys Were Increased within 5 min of a Single High Dose Whole Body Irradiation.

To understand the ultra-early reaction of normal organ lipids during irradiation, we investigated the response of lipids, including polyunsaturated fatty acid (PUFA) chains, which are particularly susceptible to damage by ROS, in mice's kidneys, lungs, brains, and livers within 5 min of single high-dose irradiation. In this study, we set up three groups of C56BL/6 male mice and conducted whole-body irradiation with 0 Gy, 10 Gy, and 20 Gy single doses. Kidney, lung, brain, and liver tissues were collected within 5 min of irradiation. PUFA-targeted and whole lipidomic analyses were conducted using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The results showed that PUFA chains of kidney phosphatidylcholine (PC), phosphatidylethanolamine (PE), and triacylglycerol (TG) significantly increased within 5 min of 10 Gy and 20 Gy irradiation. The main components of increased PUFA chains in PC and PE were C18:2, C20:4, and C22:6, and in TG the main component was C18:2. The kidney lipidomes also showed significant changes from the perspective of lipid species, mainly dominated by an increase in PC, PE, TG, and signal lipids, while lipidomes of the lung, brain, and liver were slightly changed. Our results revealed that acute PUFA chains increase and other lipidomic changes in the kidney upon whole-body irradiation within 5 min of irradiation. The significantly increased lipids also showed a consistent preference for possessing PUFA chains. The lipidomic changes varied from organ to organ, which indicates that the response upon irradiation within a short time is tissue-specific.

The royal food of termites shows king and queen specificity.

Society in eusocial insects is based on the reproductive division of labor, with a small number of reproductive individuals supported by a large number of nonreproductive individuals. Because inclusive fitness of all colony members depends on the survival and fertility of reproductive members, sterile members provide royals with special treatment. Here, we show that termite kings and queens each receive special food of a different composition from workers. Sequential analysis of feeding processes demonstrated that workers exhibit discriminative trophallaxis, indicating their decision-making capacity in allocating food to the kings and queens. Liquid chromatography tandem-mass spectrometry analyses of the stomodeal food and midgut contents revealed king- and queen-specific compounds, including diacylglycerols and short-chain peptides. Desorption electrospray ionization mass spectrometry imaging analyses of 13C-labeled termites identified phosphatidylinositol and acetyl-l-carnitine in the royal food. Comparison of the digestive tract structure showed remarkable differences in the volume ratio of the midgut-to-hindgut among castes, indicating that digestive division of labor underlies reproductive division of labor. Our demonstration of king- and queen-specific foods in termites provides insight into the nutritional system that underpins the extraordinary reproduction and longevity of royals in eusocial insects.

Plastic brain structure changes associated with the division of labor and aging in termites.

Division of labor is a prominent feature of social insect societies, where different castes engage in different specialized tasks. As brain differences are associated with behavioral differences, brain anatomy may be linked to caste polymorphism. Here, we show that termite brain morphology changes markedly with caste differentiation and age in the termite, Reticulitermes speratus. Brain morphology was shown to be associated with reproductive division of labor, with reproductive individuals (alates and neotenic reproductives) having larger brains than nonreproductives (workers and soldiers). Micro-computed tomography (CT) imaging and dissection observations showed that the king's brain morphology changed markedly with shrinkage of the optic lobes during their long life in the dark. Behavioral experiments showed that mature primary kings lose visual function as a result of optic lobe shrinkage. These results suggested that termites restructure their nervous systems to perform necessary tasks as they undergo caste differentiation, and that they also show flexible changes in brain morphology even after the final molt. This study showed that brain morphology in social insects is linked to caste and aging, and that the evolution of the division of labor is underpinned by the development of diverse neural systems for specialized tasks.

Lipidomics-based tissue heterogeneity in specimens of luminal breast cancer revealed by clustering analysis of mass spectrometry imaging: A preliminary study.

Cancer tissues reflect a greater number of pathological characteristics of cancer compared to cancer cells, so the evaluation of cancer tissues can be effective in determining cancer treatment strategies. Mass spectrometry imaging (MSI) can evaluate cancer tissues and even identify molecules while preserving spatial information. Cluster analysis of cancer tissues' MSI data is currently used to evaluate the phenotype heterogeneity of the tissues. Interestingly, it has been reported that phenotype heterogeneity does not always coincide with genotype heterogeneity in HER2-positive breast cancer. We thus investigated the phenotype heterogeneity of luminal breast cancer, which is generally known to have few gene mutations. As a result, we identified phenotype heterogeneity based on lipidomics in luminal breast cancer tissues. Clusters were composed of phosphatidylcholine (PC), triglycerides (TG), phosphatidylethanolamine, sphingomyelin, and ceramide. It was found that mainly the proportion of PC and TG correlated with the proportion of cancer and stroma on HE images. Furthermore, the number of carbons in these lipid class varied from cluster to cluster. This was consistent with the fact that enzymes that synthesize long-chain fatty acids are increased through cancer metabolism. It was then thought that clusters containing PCs with high carbon counts might reflect high malignancy. These results indicate that lipidomics-based phenotype heterogeneity could potentially be used to classify cancer for which genetic analysis alone is insufficient for classification.

Impact of Radiation Dose on Treatment of Maxillary Cancer With Superselective Intra-arterial Cisplatin With Radiotherapy.

BACKGROUND/AIM: Maxillary sinus cancer is a relatively rare disease, and treatment is still evolving. We compared the efficacy of superselective intra-arterial infusion of high-dose cisplatin (CDDP) with concomitant radiotherapy (RADPLAT) using three-dimensional conformal radiotherapy (3DCRT) or intensity-modulated radiotherapy (IMRT) and analyzed the relationship between the total radiation dose and the treatment outcome in localized maxillary sinus cancer. PATIENTS AND METHODS: We reviewed the cases of 58 patients with localized maxillary sinus cancer treated with RADPLAT at our institution from March 2004 to November 2020. These 58 patients included 34 who received 3DCRT and 24 who received IMRT. RESULTS: The median follow-up period was 38.4 months. The median prescribed dose to the local lesion was 66 Gy in the 3DCRT group and 70 Gy in the IMRT group. CDDP (100-120 mg/m2) was administered once a week for a median of 6 cycles. The 5-year local control rate and overall survival rate were 69.9% and 72.2%, respectively. The patients treated with 70 Gy had a significantly higher local control rate (87.7%) than those treated with 60 Gy or less (41.0%) (p=0.011). No late grade 3 or higher eye disorders except for cataracts developed in the IMRT group, while grade 4 eye disorders occurred in four patients receiving 3DCRT. CONCLUSION: IMRT can escalate radiation dose safely with acceptable toxicities. The total dose may have an impact on the local control rate in RADPLAT.

Radiotherapy for ductal carcinoma of the prostate: an analysis based on the Japanese radiation oncology study group survey.

BACKGROUND: The clinical characteristics of prostate ductal carcinoma is still unclear, and treatment strategy has not yet been established due to its rarity. Therefore, we conducted a multicenter survey of radiation therapy for prostate ductal carcinoma in Japan. METHOD: Data of patients with ductal carcinoma of the prostate treated with radiation therapy between 1996 and 2018 were extracted from the database of each facility. RESULTS: Fifty-two treatment records of 41 patients were collected from nine institutions. The treatment purpose and situations were varied curative intent to palliation. Twenty-eight patients received curative treatments. The median follow-up period of these patients was 68 months. Androgen deprivation therapy was combined with radiation therapy in 26 cases (93%). X-ray and particle irradiation was used. Radiation dose range was 63-78 Gy; 5-year overall survival, progression-free survival and biochemical relapse-free survival were 87.0, 79.3 and 79.3%, respectively. One patient experienced Grade 3 radiation proctitis and one experienced Grade 3 radiation cystitis. There were no Grade 4 or worse adverse events. CONCLUSION: Most patient received similar treatment with adenocarcinoma of prostate, and the clinical results were compatible. For more reliable evidence, further studies are required.

Feasibility of linac-based fractionated stereotactic radiotherapy and stereotactic radiosurgery for patients with up to ten brain metastases.

BACKGROUND: Linac-based fractionated stereotactic radiotherapy (fSRT) and stereotactic radiosurgery (SRS) are increasingly being used to manage patients with multiple metastases. This retrospective cohort study aimed to compare the outcomes after linac-based fSRT and SRS between three patient groups classified based on the number of brain metastases (BMs): 1 BM, 2-4 BM, 5-10 BM. METHODS: The data of consecutive patients with 1-10 BMs treated with fSRT or SRS between July 2016 and June 2018 at a single institution were collected. Patients with previous whole-brain radiotherapy (WBRT), concurrent use of WBRT, or surgical resection were excluded from the analysis. A total of 176 patients were classified into three groups according to the number of BMs: 78, 67, and 31 patients in 1 BM, 2-4 BM, and 5-10 BM, respectively. The Kaplan-Meier method was used to estimate overall survival (OS) curves, and the cumulative incidence with competing risks was used to estimate local control (LC), distant intracranial failure (DIF), and radiation necrosis (RN). RESULTS: Median OS was 19.8 months (95% confidence interval [CI] 10.2-27.5), 7.3 months (4.9-11.1), and 5.1 months (4.0-9.0) in 1 BM, 2-4 BM, and 5-10 BM, respectively. Compared to 2-4 BM, 1 BM had significantly better OS (hazard ratio [HR] 0.59, 95% CI 0.40-0.87; p = 0.0075); however, 5-10 BM had comparable OS (HR 1.36, 95% CI 0.85-2.19; p = 0.199). There was no significant difference in LC, DIF, and RN between tumor number groups, but DIF was lower in 1 BM. RN of grade 2 or higher occurred in 21 patients (13.5%); grade 4 and 5 RN were not observed. CONCLUSIONS: The linac-based fSRT and SRS for patients with 5-10 BMs is comparable to that for patients with 2-4 BMs in OS, LC, DIF, and RN. It seems reasonable to use linac-based fSRT and SRS in patients with 5-10 BMs.

Rectourethral fistula after external beam radiotherapy for prostate cancer in a patient with thromboangiitis obliterans: A case report.

INTRODUCTION: Thromboangiitis obliterans (TAO) is a rare disease of unknown cause that causes segmental vasculitis in peripheral blood vessels. It is uncertain whether its presence causes serious adverse events in patients receiving external beam radiotherapy. PATIENT CONCERNS: A 73-year-old Japanese man with prostate cancer underwent external beam radiotherapy. DIAGNOSIS: After completion of radiotherapy, fingertip pain occurred, leading to the diagnosis of TAO. INTERVENTIONS: The patient was instructed to stop smoking, but was unable to do so. OUTCOMES: Nine months after the completion of radiotherapy, fecaluria appeared, and a rectourethral fistula was diagnosed by contrast enema. The patient's TAO was poorly controlled, and the patient died from aspiration pneumonia 33 months after completion of the radiotherapy regimen. No tumor recurrence was observed during this process, and there were no risk factors other than TAO that may have formed a rectourethral fistula. LESSONS: This is the first report of rectourethral fistula caused by external beam radiotherapy for prostate cancer in which TAO was suspected to be involved. Although little is known about the relationship between TAO and radiotherapy, it should be noted that radiotherapy itself may increase the risk of normal tissue toxicity in patients with TAO.

A newly developed patient fixation system using a dedicated mouthpiece and dental impression materials for head and neck radiotherapy: a preliminary study.

We evaluated the basic characteristics and efficacy of our newly developed patient fixation system for head and neck radiotherapy that uses a dedicated mouthpiece and dental impression materials. The present investigation demonstrated that with this system, the changes in the absorbed dose to water depending on the material of the mouthpiece were small, with a maximum of 0.32% for a 10-MV photon beam. For the dental impression material, we selected a silicone material with the lowest Hounsfield unit (HU) value that had little effect on the generation of artifacts and the quality of the X-ray beam. Multiphase magnetic resonance imaging (MRI) revealed that the head-up and -down motions in the thermoplastic shell without the mouthpiece were 5.76 ± 1.54 mm, whereas the motion with the mouthpiece decreased significantly to 1.72 ± 0.92 mm (P = 0.006). Similarly, the head-left and -right motion displacement decreased from 6.32 ± 1.86 mm without the mouthpiece to 1.80 ± 0.42 mm with the mouthpiece (P = 0.003). Regarding the tongue depressor function of the mouthpiece, the median distance from the hard palate to the surface of the tongue was 28.42 mm. The present results indicate that the new immobilization device developed herein that uses a mouthpiece and a thermoplastic shell is useful for suppressing patients' head motions and tongue positions.

Development of a novel airbag system of abdominal compression for reducing respiratory motion: preliminary results in healthy volunteers.

This study used cine-magnetic resonance imaging (cine-MRI) to evaluate the safety and efficacy of a novel airbag system combined with a shell-type body fixation system in reducing respiratory motion in normal volunteers. The airbag system consists of a six-sided polygon inflatable airbag, a same shape plate, a stiff air supply tube, an air-supply pump and a digital pressure load cell monitor. Piezoelectric sensors were installed in the plate to detect compression pressure load changes; pressure load data were transferred to the digital pressure load cell monitor through Bluetooth. Five volunteers underwent cine-MRI with and without airbag compression to detect differences in the respiratory motion of the organs. The volunteers' physiologic signs were stable during the experiment. The maximum inspiration pressure load was 4.48 ± 0.86 kgf (range, 4.00-6.00 kgf), while the minimum expiration pressure load was 3.69 ± 0.95 kgf (range, 2.8-5.3 kgf). Under airbag compression, the right diaphragm movement was reduced from 19.50 ± 6.43 mm to 9.60 ± 3.61 mm (P < 0.05) in the coronal plane and 23.12 ± 6.30 mm to 11.00 ± 3.69 mm (P < 0.05) in the sagittal plane. The left diaphragm, pancreas and liver in the coronal plane and the right kidney and liver in the sagittal plane also showed significant movement reduction. This novel airbag abdominal compression system was found to be safe during the experiment and successful in the reduction of internal organ respiratory motion and promises to be a convenient and efficient tool for clinical radiotherapy.

A predictive model for pain response following radiotherapy for treatment of spinal metastases.

To establish a predictive model for pain response following radiotherapy using a combination of radiomic and clinical features of spinal metastasis. This retrospective study enrolled patients with painful spine metastases who received palliative radiation therapy from 2018 to 2019. Pain response was defined using the International Consensus Criteria. The clinical and radiomic features were extracted from medical records and pre-treatment CT images. Feature selection was performed and a random forests ensemble learning method was used to build a predictive model. Area under the curve (AUC) was used as a predictive performance metric. 69 patients were enrolled with 48 patients showing a response. Random forest models built on the radiomic, clinical, and 'combined' features achieved an AUC of 0.824, 0.702, 0.848, respectively. The sensitivity and specificity of the combined features model were 85.4% and 76.2%, at the best diagnostic decision point. We built a pain response model in patients with spinal metastases using a combination of clinical and radiomic features. To the best of our knowledge, we are the first to examine pain response using pre-treatment CT radiomic features. Our model showed the potential to predict patients who respond to radiation therapy.

Multi-institutional retrospective analysis of ultrahypofractionated radiotherapy for Japanese prostate cancer patients.

To report outcomes and risk factors of ultrahypofractionated (UHF) radiotherapy for Japanese prostate cancer patients. This multi-institutional retrospective analysis comprised 259 patients with localized prostate cancer from 6 hospitals. A total dose of 35-36 Gy in 4-5 fractions was prescribed for sequential or alternate-day administration. Biochemical failure was defined according to the Phoenix ASTRO consensus. Toxicities were assessed using National Cancer Institute Common Toxicity Criteria version 4. Tumor control and toxicity rates were analyzed by competing risk frames. Median follow-up duration was 32 months (range 22-97 months). 2- and 3-year biochemical control rates were 97.7% and 96.4%, respectively. Initial prostate-specific antigen (p < 0.01) and neoadjuvant androgen deprivation therapy (p < 0.05) were identified as risk factors for biochemical recurrence. 2- and 3-year cumulative ≥ Grade 2 late genitourinary (GU) toxicities were 5.8% and 7.4%, respectively. Corresponding rates of gastrointestinal (GI) toxicities were 3.9% and 4.5%, respectively. Grade 3 rates were lower than 1% for both GU and GI toxicities. No grade 4 or higher toxicities were encountered. Biologically effective dose was identified as a risk factor for ≥ Grade 2 late GU and GI toxicities (p < 0.05). UHF radiotherapy offered effective, safe treatment for Japanese prostate cancer with short-term follow-up. Our result suggest higher prescribed doses are related to higher toxicity rates.

Efficacy of Spacers in Radiation Therapy for Locally Advanced Pancreatic Cancer: A Planning Study.

BACKGROUND/AIM: We aimed to investigate the dosimetric effects of a spacer placed between the pancreas and surrounding gastrointestinal structures in intensity-modulated radiation therapy (IMRT) planning to provide more effective radiation therapy for locally advanced pancreatic cancer (LAPC). PATIENTS AND METHODS: Treatment planning was performed for six patients with LAPC based on computed tomography images without spacers and with 5-mm or 10-mm spacers virtually inserted under the supervision of a hepatobiliary pancreatic surgeon. The prescription dose was 63 Gy in 28 fractions. RESULTS: With the exception of one case of pancreatic head cancer, planning target volume receiving ≥95% of the prescribed dose (PTV V95) was achieved by 90% or more by inserting a spacer, and by 95% or more in all 3 cases of pancreatic body and tail cancer by inserting a 10-mm spacer. CONCLUSION: IMRT with appropriate spacer placement may help provide high-dose treatment for LAPC and improve associated patient outcomes.

The relationship between the quantitative evaluation of thyroid bed uptake and the disappearance of accumulation in adjuvant radioactive iodine therapy for differentiated thyroid cancer.

OBJECTIVE: Iodine-131 (I-131) radioactive iodine therapy (RAI) after total thyroidectomy is the standard treatment for patients with differentiated thyroid cancer (DTC). We investigated the relationship between the quantitative parameters of the iodine uptake and the disappearance of the accumulation in the thyroid bed in adjuvant therapy using a 1.11 GBq or 3.70 GBq dose of I-131. METHODS: We retrospectively analyzed the cases of 40 patients with DTC who were treated with RAI at our institution between April 2017 and August 2019. The patients were treated with the I-131 dose of 1.11 GBq (n = 25) or 3.70 GBq (n = 15) after total thyroidectomy. The I-131 whole-body scan and hybrid single-photon emission computed tomography/X-ray computed tomography (SPECT/CT) were performed 3 days after RAI. Using image analysis software, we measured the standardized uptake value (SUV) and absolute radioactivity concentration (kBq/ml) on the target lesions with the highest uptake in the thyroid bed. RESULTS: The median period from RAI to the evaluation of the absence of uptake of the thyroid bed was 6.75 months. After RAI, uptake of the thyroid bed disappeared in 26 of the 40 patients. The disappearance rate was significantly higher in the 3.70 GBq group than in the 1.11 GBq group (86.7% vs. 52.0%, respectively; p = 0.029). However, there were no significant differences in the values of kBq/ml or SUV between the 1.11 GBq group and 3.70 GBq group. On the other hand, the group in which the uptake disappeared after RAI showed significantly higher kBq/ml max and kBq/ml mean values than the group in which the uptake did not disappear after RAI (p = 0.028, p = 0.032, respectively). The SUVmax and SUVmean also tended to be higher in the disappeared-uptake group than the not-disappeared-uptake group, but the differences were not significant (p = 0.166, p = 0.176, respectively). CONCLUSIONS: The quantitative evaluation might be useful as one of the predictive indicators of the disappearance of the accumulation of radioactive iodine in the thyroid bed.

Radical Radiation Therapy for Radiation-Induced Angiosarcoma with Local Control.

Angiosarcoma is believed to be refractory to radical radiotherapy. Although no effective treatment for radiation-induced angiosarcoma has been established, surgery is generally chosen. We report a case of unresectable radiation-induced angiosarcoma after breast cancer surgery that responded remarkably to radical radiotherapy alone. A 78-year-old Japanese female had a large mass in her right breast that was diagnosed as angiosarcoma after biopsy and considered to be a radiation-induced angiosarcoma because the patient had been treated with postoperative irradiation to the right breast cancer 8 years earlier. There were no findings suggestive of lymphadenopathy or distant metastasis. Since the tumor was widely infiltrated to the skin and the muscle layer, radical radiotherapy (total dose 66 Gy) was performed. At this radiotherapy completion, the tumor was remarkably reduced, and there were no acute adverse effects except for grade 2 dermatitis. Pazopanib was started after radiotherapy but was discontinued since necrosis of the wound with hemorrhage was observed. External pneumothorax occurred due to the marked tumor shrinkage, but it was cured by conservative care. Although angiosarcoma is well known to be radioresistant, excellent local control may be obtained by radical radiotherapy in some cases. Radiotherapy should be considered as a treatment option in inoperable cases.

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

PURPOSE: This 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. RESULTS: Both 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 purchase price, 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. CONCLUSION: Patterns 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.