Phase 1 study of simlukafusp alfa (FAP-IL2v) with or without atezolizumab in Japanese patients with advanced solid tumors.

PURPOSE: To evaluate the safety/tolerability and pharmacokinetics of simlukafusp alfa (FAP-IL2v), an immunocytokine containing an anti-fibroblast activation protein-α (FAP) antibody and an interleukin (IL)-2 variant, administered alone or with the programmed death-ligand 1 inhibitor atezolizumab, in Japanese patients with advanced solid tumors. PATIENTS AND METHODS: In this phase 1, open-label, dose-escalation study, patients received intravenous (IV) FAP-IL2v at 10 or 15/20 mg alone or 10 mg when combined with IV atezolizumab. Primary objectives were identification of dose-limiting toxicities (DLTs), recommended dose (RD), and maximum tolerated dose (MTD), and evaluation of the safety/tolerability and pharmacokinetics of FAP-IL2v alone and combined with atezolizumab. RESULTS: All 11 patients experienced adverse events (AEs) during FAP-IL2v treatment. Although most AEs were of mild severity, four treatment-related AEs led to study treatment discontinuation in two patients; one with infusion-related reaction, hypotension, and capillary leak syndrome, and the other with aspartate aminotransferase increased. No AE-related deaths occurred. One DLT (Grade 3 hypotension) occurred in a patient receiving FAP-IL2v 15/20 mg alone. The RD and MTD could not be determined. Pharmacokinetics of FAP-IL2v remained similar with or without atezolizumab. The study was terminated early as FAP-IL2v development was discontinued due to portfolio prioritization (not for efficacy/safety reasons). CONCLUSIONS: This study describes the safety/tolerability of FAP-IL2v 10 mg alone and in combination with atezolizumab in Japanese patients with advanced solid tumors; one DLT (hypotension) occurred with FAP-IL2v 15/20 mg. However, dose escalation of FAP-IL2v was not conducted due to early study termination.

Impact of Durvalumab on the Duration and Complexity of Corticosteroid Therapy for Pneumonitis After Chemoradiotherapy.

INTRODUCTION: It is unclear how the duration and tapering pattern of corticosteroid therapy for pneumonitis changed after the introduction of durvalumab consolidation therapy. METHODS: We retrospectively evaluated the medical records of patients diagnosed with nonsmall cell lung cancer who received chemoradiotherapy between January 2014 and December 2020. RESULTS: Data for 135 patients treated before durvalumab approval and 100 patients treated with durvalumab after its approval were analyzed. In both groups, more than 70% were male, with a median age of 66 y. Approximately 85% were smokers, and the most common tumor histology was adenocarcinoma. Most patients were treated with doses of 60 and 66 Gy (n = 127 [94%] vs. n = 95 [95%]). Among the patients treated with durvalumab, 57%, 38%, and 5% had grade 1, grade 2, and grade 3 pneumonitis; none had grade 4 or 5 pneumonitis. Patients treated with durvalumab exhibited a longer duration of corticosteroid therapy for pneumonitis (17 wk; range: 2-88 wk) than patients not treated with durvalumab (7 wk; range: 0.4-21 wk; P < 0.001). Pneumonitis relapse was more frequent in patients treated with durvalumab (n = 8; 23%) than in patients not treated with durvalumab (n = 2; 7%). Among the 8 patients treated with durvalumab, 2 had recurrent pneumonitis, 1 could not terminate corticosteroids. CONCLUSIONS: Our data show that durvalumab prolongs the duration of corticosteroid therapy and increases the complexity of corticosteroid tapering patterns. This study can help manage pneumonitis caused by immune checkpoint inhibitors and other drugs used after chemoradiotherapy in routine practice and clinical trials.

The remarkable antitumor efficacy of corticosteroid treatment in patients with refractory thymomas.

BACKGROUND: Some case reports have found that corticosteroid treatments shrunk thymoma lesions remarkably after the failure of chemotherapy or surgery. However, few studies have comprehensibly evaluated the antitumor effects of corticosteroids in patients with invasive thymomas. METHODS: We reviewed the medical records of 13 consecutively enrolled patients with locally advanced or metastatic thymomas treated via corticosteroid monotherapies from January 2010 to March 2021 in our institute. A Cox's proportional hazard model and the Kaplan-Meier method were used to identify factors associated with survival. RESULTS: The median follow-up time was 26 months (range, 13-115 months). The median initial dose of corticosteroid was 0.90 mg/kg/day prednisolone equivalent (range, 0.4-1.1 mg/kg/day). Of the 13 cases, 7 (53.8%, 95% CI: 0.25-0.81) exhibited a partial response and 5 (38.5%, 95% CI: 0.14-0.68) stable disease. The median progression-free survival was 5.7 months [95% confidence interval (CI): 1.5-9.6 months]. The median overall survival was 25.3 months (95% CI: 7.1-not attained). The median duration of corticosteroid use was 3 months (range, 1-64 months). Patients with WHO subtype B thymomas exhibited a better overall response rate to corticosteroids than did patients with other disease subtypes (75%, 95% CI: 0.19-0.99). Adverse events of Grade 3 or more were not observed. CONCLUSIONS: Corticosteroids are clinically valuable for patients with thymomas.

Mechanism of ERBB2 gene overexpression by the formation of super-enhancer with genomic structural abnormalities in lung adenocarcinoma without clinically actionable genetic alterations.

BACKGROUND: In an extensive genomic analysis of lung adenocarcinomas (LUADs), driver mutations have been recognized as potential targets for molecular therapy. However, there remain cases where target genes are not identified. Super-enhancers and structural variants are frequently identified in several hundred loci per case. Despite this, most cancer research has approached the analysis of these data sets separately, without merging and comparing the data, and there are no examples of integrated analysis in LUAD. METHODS: We performed an integrated analysis of super-enhancers and structural variants in a cohort of 174 LUAD cases that lacked clinically actionable genetic alterations. To achieve this, we conducted both WGS and H3K27Ac ChIP-seq analyses using samples with driver gene mutations and those without, allowing for a comprehensive investigation of the potential roles of super-enhancer in LUAD cases. RESULTS: We demonstrate that most genes situated in these overlapped regions were associated with known and previously unknown driver genes and aberrant expression resulting from the formation of super-enhancers accompanied by genomic structural abnormalities. Hi-C and long-read sequencing data further corroborated this insight. When we employed CRISPR-Cas9 to induce structural abnormalities that mimicked cases with outlier ERBB2 gene expression, we observed an elevation in ERBB2 expression. These abnormalities are associated with a higher risk of recurrence after surgery, irrespective of the presence or absence of driver mutations. CONCLUSIONS: Our findings suggest that aberrant gene expression linked to structural polymorphisms can significantly impact personalized cancer treatment by facilitating the identification of driver mutations and prognostic factors, contributing to a more comprehensive understanding of LUAD pathogenesis.

Response to dabrafenib plus trametinib on a rare BRAF mutation (V600_W604 deletion-insertion R) in an advanced non-small cell lung cancer patient.

Although dabrafenib plus trametinib has been approved for BRAF V600E mutation positive advanced non-small cell lung cancer (NSCLC), data on its efficacy against uncommon BRAF mutations are still limited due to their rare frequency. We report a case of 70-year-old woman with BRAF V600_W604 deletion-insertion R-positive stage IVA lung adenocarcinoma, who was successfully treated with dabrafenib plus trametinib. Herein, we discuss the oncogenic role of uncommon BRAF mutations and highlight the importance of performing comprehensive genomic profiling on patients without any targetable gene alterations in companion diagnostics.

Recommendation for reducing the crystalline lens exposure dose by reducing imaging field width in cone-beam computed tomography for image-guided radiation therapy: an anthropomorphic phantom study.

In cone-beam computed tomography (CBCT) for image-guided radiation therapy (IGRT) of the head, we evaluated the exposure dose reduction effect to the crystalline lens and position-matching accuracy by narrowing one side (X2) of the X-ray aperture (blade) in the X-direction. We defined the ocular surface dose of the head phantom as the crystalline lens exposure dose and measured using a radiophotoluminescence dosimeter (RPLD, GD-352 M) in the preset field (13.6 cm) and in each of the fields when blade X2 aperture was reduced in 0.5 cm increments from 10.0 to 5.0 cm. Auto-bone matching was performed on CBCT images acquired five times with blade X2 aperture set to 13.6 cm and 5.0 cm at each position when the head phantom was moved from - 5.0 to + 5.0 mm in 1.0 mm increment. The maximum reduction rate in the crystalline lens exposure dose was - 38.7% for the right lens and - 13.2% for the left lens when blade X2 aperture was 5.0 cm. The maximum difference in the amount of position correction between blade X2 aperture of 13.6 cm and 5.0 cm was 1 mm, and the accuracy of auto-bone matching was similar. In CBCT of the head, reduced blade X2 aperture is a useful technique for reducing the crystalline lens exposure dose while ensuring the accuracy of position matching.

Rapid Response to Lenvatinib and Disease Flare After Discontinuation in a Patient With Thymic Carcinoma Harboring KIT Exon 11 Mutation: A Case Report.

Lenvatinib, a multitarget tyrosine kinase inhibitor for c-Kit and other kinases, has exhibited promising efficacy in treating advanced or metastatic thymic carcinoma (TC). Here, we present the case of a patient with metastatic TC harboring a KIT exon 11 deletion and amplification. The patient exhibited a remarkable response to lenvatinib but experienced rapid disease progression after discontinuation of lenvatinib, referred to as a "disease flare." This case report indicates that KIT mutations and amplification can predict lenvatinib response in patients with TC. However, in such cases, there might be a risk of disease flares after lenvatinib discontinuation.

Leaf trichome-mediated predator effects on the distribution of herbivorous mites within a kidney bean plant.

Some predators prefer to settle on leaf patches with microstructures (e.g., trichomes and domatia), leaving traces on the patches. Herbivorous arthropods, in turn, select leaf patches in response to these traces left by predators. It remains unclear whether traces of predators on leaf patches affect the distribution of herbivorous prey within plants through plant microstructure. Therefore, we examined the distribution of herbivorous mite (Tetranychus urticae) and predatory mite (Phytoseiulus persimilis) by investigating their oviposition pattern. We used a kidney bean plant (Phaseolus vulgaris) with two expanded primary leaves and the first trifoliate leaf, focusing on leaf trichomes as the microstructure. The density of trichomes was higher on the first trifoliate leaf than on the primary leaves and on the abaxial surface of the leaves than on the adaxial surface. Adult female P. persimilis laid more eggs on the first trifoliate leaf to the primary leaves. Although adult female T. urticae preferred to oviposit on the abaxial surface of primary leaves, previous exposure of plants to predators diminished this preference. The altered egg distribution would be a response to the traces of P. persimilis rather than eggs of P. persimilis. Our findings indicate that T. urticae reproduces on leaf patches with traces of predators without altering their oviposition preference. Given that the presence of predator traces is known to reduce the reproduction of T. urticae, it may have a substantial effect on the population of T. urticae in the next generations on kidney bean plants.

Clinical significance of inter-assay discrepancy in PD-L1 evaluation for the efficacy of pembrolizumab in advanced NSCLC with high PD-L1 expression.

INTRODUCTION: Programmed cell death ligand-1 (PD-L1) expression is a predictive biomarker for the efficacy of anti-programmed cell death receptor-1/PD-L1 antibodies in advanced non-small cell lung cancer (NSCLC). Although several assays have been approved for evaluating PD-L1 expression status, inter-assay discordance has been observed between some assays. The clinical significance of these discrepancies is still unclear. METHODS: We retrospectively reviewed treatment-naïve NSCLC patients whose PD-L1 expression was evaluated using both 22C3 and SP142 assays. Among those, efficacy analysis was performed for patients with PD-L1 tumor proportion score (TPS) ≥ 50 % (22C3), who had received first-line pembrolizumab monotherapy. Additionally, transcriptome analysis was conducted in the available tumors with TPS ≥ 50 % to investigate the distinct immune profiles that accompany inter-assay discordance. RESULTS: In total, 611 patients were eligible. Among 198 patients with TPS ≥ 50 %, 91 (46 %) had tumor cell score ≤ 1 (SP142, i.e., inter-assay discrepancy). In the 52 patients who received first-line pembrolizumab monotherapy, treatment efficacy was significantly lower in patients with the discrepancy than that in those without (objective response rate: 18 % vs. 83 %, p < 0.001; median progression-free survival [months]: 3.2 vs. 8.3, p < 0.001). Transcriptome analysis revealed significantly more CD274 splice variants with aberrant 3'-terminal sequences in tumors with the inter-assay discrepancy than in those without. CONCLUSION: The inter-assay discrepancy in the PD-L1 status of tumor cells between the 22C3 and SP142 assays, reflecting an imbalance in the CD274 splice variants, could be a biomarker for primary resistance against pembrolizumab monotherapy in high PD-L1-expressing NSCLCs.

Efficacy and safety of chemoimmunotherapy in advanced non-small cell lung cancer patients with antibiotics-induced dysbiosis: a propensity-matched real-world analysis.

PURPOSE: The gut microbiota is hypothesized as a prognostic biomarker for cancer immunotherapy. Antibiotic-induced dysbiosis negatively affects the clinical outcomes of immunotherapy. However, the effect of dysbiosis on the efficacy and safety of Chemoimmunotherapy (chemo-IOs), the frontline standard of care, in advanced non-small cell lung cancer (NSCLC) remains unknown. We aimed to compare the efficacy and safety of chemo-IOs in patients exposed to antibiotics before treatment with those of patients who were not exposed. METHODS: We retrospectively reviewed patients with advanced NSCLC treated with first-line chemo-IOs between 2018 and 2020 at the National Cancer Center Hospital. The patients were divided into two groups: those exposed to antibiotics within 30 days before induction therapy (ABx group) and those did not antibiotics (Non-ABx group). Propensity score matching was used to control for potential confounding factors. Clinical outcomes including progression-free survival (PFS), overall survival (OS), and immune-related adverse events (irAEs) were compared. RESULTS: Of 201 eligible patients, 21 were in the ABx group, and 42 were in the non-ABx group after propensity score matching. No differences in PFS or OS emerged between the two groups (ABx group vs. Non-ABx group) (PFS:7.0 months vs. 6.4 months, hazard ratio [HR] 0.89; 95% confidence interval [CI], 0.49-1.63, OS:20.4 months vs. 20.1 months, HR 0.87; 95% CI 0.44-1.71). The frequency of irAEs before propensity score matching was similar across any-grade irAEs (39.4% vs. 42.9%) or grade 3 or higher irAEs (9.1% vs. 11.3%). CONCLUSION: Antibiotic-induced dysbiosis may not affect the efficacy of chemo-IOs in patients with advanced NSCLC.

Advances in cancer DNA methylation analysis with methPLIER: use of non-negative matrix factorization and knowledge-based constraints to enhance biological interpretability.

DNA methylation is an epigenetic modification that results in dynamic changes during ontogenesis and cell differentiation. DNA methylation patterns regulate gene expression and have been widely researched. While tools for DNA methylation analysis have been developed, most of them have focused on intergroup comparative analysis within a dataset; therefore, it is difficult to conduct cross-dataset studies, such as rare disease studies or cross-institutional studies. This study describes a novel method for DNA methylation analysis, namely, methPLIER, which enables interdataset comparative analyses. methPLIER combines Pathway Level Information Extractor (PLIER), which is a non-negative matrix factorization (NMF) method, with regularization by a knowledge matrix and transfer learning. methPLIER can be used to perform intersample and interdataset comparative analysis based on latent feature matrices, which are obtained via matrix factorization of large-scale data, and factor-loading matrices, which are obtained through matrix factorization of the data to be analyzed. We used methPLIER to analyze a lung cancer dataset and confirmed that the data decomposition reflected sample characteristics for recurrence-free survival. Moreover, methPLIER can analyze data obtained via different preprocessing methods, thereby reducing distributional bias among datasets due to preprocessing. Furthermore, methPLIER can be employed for comparative analyses of methylation data obtained from different platforms, thereby reducing bias in data distribution due to platform differences. methPLIER is expected to facilitate cross-sectional DNA methylation data analysis and enhance DNA methylation data resources.

Immunogenicity after vaccination of COVID-19 vaccines in patients with cancer: a prospective, single center, observational study.

BACKGROUND: Patients with cancer, particularly those undergoing chemotherapy, are at risk from the low immunogenicity of Coronavirus Disease 19 (COVID-19) vaccines. METHODS: This prospective study assessed the seroconversion rate of COVID-19 vaccines among patients with cancer and hospital staff. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein-specific IgG (S-IgG) concentrations were evaluated before the first vaccination, and 1-3 and 4-6 months after the second vaccination. The primary endpoint was the seroconversion rate measured 1-3 months after the second vaccine. RESULTS: In total, 590 patients and 183 healthy hospital staff were analyzed. At 1-3 months after the second vaccination, the S-IgG antibody concentration exceeded the cut-off value (20 BAU/mL) in 96.1% (567/590) of the patients with cancer and 100% (183/183) of the healthy controls (p = 0.0024). At 4-6 months after the second vaccination, the S-IgG antibody concentration exceeded the cut-off value (20 BAU/ml for S-IgG) in 93.1% (461/495) of the patients with cancer and 100% (170/170) of the healthy controls (p < 0.0001). Old age, being male, and low lymphocyte count were related to low SARS-CoV-2 S-IgG levels 1-3 months after the second vaccination among patients, while body mass index, smoking history, and serum albumin level were not. Patients undergoing platinum combination therapy and alkylating agent among cytotoxic drugs, and PARP inhibitor, mTOR inhibitor, and BCR-ABL inhibitor exhibited a low S-IgG antibody concentration compared to the no treatment group. CONCLUSIONS: COVID-19 vaccine immunogenicity was reduced among patients with cancer, especially under several treatment regimens.

Atmospheric formaldehyde production on early Mars leading to a potential formation of bio-important molecules.

Formaldehyde (H2CO) is a critical precursor for the abiotic formation of biomolecules, including amino acids and sugars, which are the building blocks of proteins and RNA. Geomorphological and geochemical evidence on Mars indicates a temperate environment compatible with the existence of surface liquid water during its early history at 3.8-3.6 billion years ago (Ga), which was maintained by the warming effect of reducing gases, such as H2. However, it remains uncertain whether such a temperate and weakly reducing surface environment on early Mars was suitable for producing H2CO. In this study, we investigated the atmospheric production of H2CO on early Mars using a 1-D photochemical model assuming a thick CO2-dominated atmosphere with H2 and CO. Our results show that a continuous supply of atmospheric H2CO can be used to form various organic compounds, including amino acids and sugars. This could be a possible origin for the organic matter observed on the Martian surface. Given the previously reported conversion rate from H2CO into ribose, the calculated H2CO deposition flux suggests a continuous supply of bio-important sugars on early Mars, particularly during the Noachian and early Hesperian periods.

Adenovirus pneumonia mimicking osimertinib-induced pneumonitis in a patient with advanced NSCLC with EGFR mutation: A case report.

Drug-related pneumonitis (DRP) caused by epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs) is a fatal adverse event in patients with EGFR-mutant non-small cell lung cancer (NSCLC). The diagnosis of DRP is based on radiological findings, the temporal association of presentation with the initiation of a systemic therapeutic agent, and the exclusion of other likely causes. Here we report a case in which severe adenoviral pneumonia mimicking DRP occurred during treatment with osimertinib, and osimertinib was successfully resumed after recovery from adenoviral pneumonia.

Distinct Progression and Efficacy of First-Line Osimertinib Treatment According to Mutation Subtypes in Metastatic NSCLC Harboring EGFR Mutations.

Introduction: Osimertinib (OSI), a third-generation EGFR tyrosine kinase inhibitor, is the standard treatment for patients with naive EGFR-mutant NSCLC. Nevertheless, information on how the mutation subtype affects disease progression after the failure of OSI treatment is scarce. Methods: We retrospectively reviewed patients with EGFR-mutant NSCLC who received OSI as a first-line treatment between April 2015 and December 2021. Results: This study included 229 patients. The objective response rate was 71%, with intracranial and extracranial response rates of 71% and 90%, respectively. The median progression-free survival was 23.3 mo (95% confidence interval [CI]: 19.6-26.7), and the median overall survival was 33.7 mo (95% CI: 31.3-58.6). Multivariate analysis revealed that the EGFR exon 21 L858R point mutation (L858R) (hazard ratio [HR] = 1.56, 95% CI: 1.04-2.34, p = 0.0328) and liver metastasis (HR = 2.63, 95% CI: 1.53-4.49, p = 0.0004) were significant predictors of progression-free survival in OSI treatment. The concomitant disease progression involving the central nervous system metastasis was significantly more common in patients with L858R (p = 0.048), whereas concomitant disease progression involving primary lesions was significantly more common in patients with exon 19 deletion mutation (p = 0.01). In addition, the probability of disease progression over time was higher for L858R compared with that for exon 19 deletion mutation, in patients with central nervous system metastasis (log-rank test, p = 0.027). Conclusions: The mutation subtype had an impact not only on the clinical outcome of the first-line OSI treatment but also on progression patterns after OSI treatment in patients with NSCLC harboring EGFR mutations.

Phase I study of the anti-TIGIT antibody tiragolumab in combination with atezolizumab in Japanese patients with advanced or metastatic solid tumors.

PURPOSE: Tiragolumab is a monoclonal antibody that binds to the inhibitory immune checkpoint TIGIT (T-cell immunoreceptor with Ig and ITIM domains). In early phase clinical trials, tiragolumab in combination with the programmed death-ligand 1-inhibitor atezolizumab was well tolerated and has demonstrated preliminary anti-tumor activity in patients with advanced/metastatic solid tumors. We report the results of a phase I study of tiragolumab plus atezolizumab in Japanese patients (jRCT2080224926). METHODS: Japanese patients ≥ 20 years old received tiragolumab (600 mg) and atezolizumab (1200 mg) intravenously every 21 days until unacceptable toxicity or disease progression. Primary endpoints were safety and pharmacokinetic (PK) parameters of tiragolumab plus atezolizumab. Secondary endpoints were anti-tumor activity. RESULTS: Three patients were enrolled with diagnoses of non-small cell lung cancer, pancreatic cancer, and cholangiocarcinoma. No dose-limiting toxicities were observed. Two patients experienced treatment-related adverse events (AEs) of any grade. There were no grade ≥ 3 AEs, serious AEs, AEs leading to discontinuation, modification or withdrawal of any study drug, or AEs leading to death. At cycle 1, mean PK parameters of tiragolumab were as follows: Cmax 217 µg/mL; Cmin 54.9 µg/mL; area under the concentration-time curve from 0 to the last measurable concentration, 2000 µg·day/mL; t1/2, 17.6 days. Best overall response was stable disease in two patients. CONCLUSION: Tiragolumab plus atezolizumab was well tolerated in Japanese patients with advanced/metastatic solid tumors, and no differences in tiragolumab PK characteristics were noted between Japanese patients enrolled in this study, and non-Japanese patients enrolled in a global phase Ia/Ib study. These results may support the inclusion of Japanese patients in ongoing global phase III clinical trials. TRIAL REGISTRATION NUMBER: jRCT2080224926.

[A Case of Early-Stage Cecal Cancer with Mesenteric Phlebosclerosis Requiring Laparoscopic Right Hemicolectomy of the Colon].

The patient was a 71-year-old woman diagnosed with mesenteric phlebosclerosis(MP)2 years earlier. CT performed to investigate her abdominal pain revealed an ascending colon obstruction. Colonoscopy(CS)revealed MP extending to the ascending colon hepatic flexure with stenosis and a cecal tumor(biopsy tub1). Although the cancerous lesion itself was potentially curable by endoscopic treatment, it was surgically resected because of the ascending colon stenosis caused by the MP that had also caused intestinal obstruction. Intraoperative findings revealed wall thickening and stiffening from the cecum to the ascending colon hepatic flexure. Postoperative pathological examination revealed cecal carcinoma pTis, N0, M0, pStage 0. The background mucosal tissue was consistent with MP, but no findings suggested a relationship between the MP and tumor. Although the relationship between MP and carcinogenesis is unknown, and no such relationship was identified in this case, we report this case because a further accumulation of cases of MP and carcinoma is necessary, considering the rarity of MP itself and the non-negligible number of cases with carcinoma.

[Implementation and Effectiveness of Measures to Prevent Recurrence of Incidents Developed through Root Cause Analysis Using Work Flowchart].

PURPOSE: Incidents are recommended to be analyzed by root cause analysis (RCA). Our institution also conducts RCA for incidents and takes measures to prevent recurrence. The purpose of this study was to evaluate the effectiveness of countermeasures against the root causes analyzed by RCA in order to prevent recurrence of incidents. METHODS: Since the treatment planning CT scanner was replaced, incidents of failure to zero adjustment the coordinates of the bed position occurred four times during a three-month period. The RCA was used to investigate the root causes of these incidents and to formulate measures to prevent recurrence. To evaluate the effectiveness of the recurrence prevention measures, we collected the number of recurrence of incidents during the first year after the effectiveness of the recurrence prevention measures, and used the chi-square test to determine the significant difference in the probability of an incident occurring at a significance level of 5% or less. RESULTS: The measures to prevent the recurrence of incidents were to double-check that the coordinates of the bed position were adjusted to zero and to simulate operations based on a work flow that incorporated this double-check. During the first year period following the implementation of these recurrence prevention measures, the number of recurrence incidents was zero, and the probability of their occurrence decreased statistically significantly (p<0.05). CONCLUSION: Thorough double-checks and work simulation based on the work flow are effective methods for preventing the recurrence of incidents.