Postoperative inflammatory markers predict survival in patients after McKeown esophagectomy for esophageal cancer.

BACKGROUND: Preoperative C-reactive protein-to-albumin ratio (CAR) and neutrophil-to-lymphocyte ratio (NLR) are correlated with a poor prognosis of various cancers. The significance of postoperative systemic inflammation markers for prognostic stratification of patients with esophageal cancer (EC) has not been established. Therefore, this study aimed to elucidate the impact of postoperative CAR and NLR on survival in patients with EC for prognostic stratification. METHODS: A total of 235 patients who received curative esophagectomy were analyzed. A Cox proportional hazard model was performed to detect prognostic factors. RESULTS: Multivariate analysis revealed that postoperative CAR ≥ 0.05 (hazard ratio [HR], 1.62; 95% confidence interval [CI], 1.01-2.57) and NLR ≥ 3.0 (HR, 2.81; 95% CI, 1.79-4.40) were independent prognostic factors for overall survival. Meanwhile, postoperative CAR ≥ 0.05 (HR, 1.61; 95% CI, 1.07-2.41) and NLR ≥ 3.0 (HR, 1.92; 95% CI, 1.29-2.85) were also significant prognostic factors for relapse-free survival. In addition, the patient group with postoperative CAR ≥ 0.05 and NLR ≥ 3.0 had the worst survival. CONCLUSIONS: Postoperative CAR ≥ 0.05 and NLR ≥ 3.0 can predict the poor survival of patients who received curative esophagectomy for EC.

Microscopic venous invasion is a predictor of prognosis in patients with esophageal squamous cell carcinoma undergoing ineffective neoadjuvant chemotherapy and surgery.

BACKGROUND: Neoadjuvant chemotherapy followed by surgery is Japan's most effective treatment modality for advanced thoracic esophageal squamous cell carcinoma. However, the prognosis is not as expected. This study aimed to examine prognostic factors in patients with pathologically ineffective neoadjuvant chemotherapy followed by surgery for esophageal squamous cell carcinoma. METHODS: We retrospectively analyzed patients who underwent neoadjuvant chemotherapy followed by curative esophagectomy for esophageal squamous cell carcinoma between December 2008 and July 2021. The patients were divided into the neoadjuvant chemotherapy effective group and the neoadjuvant chemotherapy ineffective group according to the pathological diagnosis. Clinicopathological data, prognosis, and recurrence were analyzed. RESULTS: A total of 143 patients (121 males, 22 females; median age, 67 years) were included in this study. Of these, 34 patients were classified into the effective group and the remaining 109 patients were assigned to the ineffective group. The ineffective group had significantly worse overall survival and recurrence-free survival than the effective group (p = 0.0192 and p = 0.0070, respectively). In the ineffective group, multivariate analysis demonstrated that microscopic venous invasion was an independent prognostic factor for overall survival (hazard ratio 2.44; 95% confidence interval 1.13-5.30) and recurrence-free survival (hazard ratio 2.43; 95% confidence interval 1.24-4.73). CONCLUSIONS: Microscopic venous invasion was associated with poor survival and cancer recurrence in the neoadjuvant chemotherapy ineffective group of patients who underwent esophagectomy for esophageal squamous cell carcinoma.

Single-cell RNA sequencing of intestinal immune cells in neonatal necrotizing enterocolitis.

PURPOSE: Necrotizing enterocolitis (NEC) causes fatal intestinal necrosis in neonates, but its etiology is unknown. We analyzed the intestinal immune response to NEC. METHODS: Using single-cell RNA sequencing (scRNA-seq), we analyzed the gene expression profiles of intestinal immune cells from four neonates with intestinal perforation (two with NEC and two without NEC). Target mononuclear cells were extracted from the lamina propria of the resected intestines. RESULTS: In all four cases, major immune cells, such as T cells (15.1-47.7%), B cells (3.1-19.0%), monocytes (16.5-31.2%), macrophages (1.6-17.4%), dendritic cells (2.4-12.2%), and natural killer cells (7.5-12.8%), were present in similar proportions to those in the neonatal cord blood. Gene set enrichment analysis showed that the MTOR, TNF-α, and MYC signaling pathways were enriched in T cells of the NEC patients, suggesting upregulated immune responses related to inflammation and cell proliferation. In addition, all four cases exhibited a bias toward cell-mediated inflammation, based on the predominance of T helper 1 cells. CONCLUSION: Intestinal immunity in NEC subjects exhibited stronger inflammatory responses compared to non-NEC subjects. Further scRNA-seq and cellular analysis may improve our understanding of the pathogenesis of NEC.

A Novel Frailty Grade Combined with Cachexia Index and Osteopenia in Esophagectomy.

BACKGROUNDS: The optimal method for evaluating frailty grade in patients with cancer has not been established in patients undergoing esophagectomy for esophageal cancer. This study aimed to clarify the impact of cachexia index (CXI) and osteopenia on survival in esophagectomized patients for esophageal cancer to develop frailty grade for risk stratification of the prognosis. METHODS: A total of 239 patients who underwent esophagectomy were analyzed. CXI was calculated as follows: skeletal muscle index × serum albumin/neutrophil-to-lymphocyte ratio. Meanwhile, osteopenia was defined as below the cutoff value of bone mineral density (BMD) calculated by the receiver operating characteristic curve. We evaluated the average Hounsfield unit within a circle in the lower midvertebral core of the 11th thoracic vertebra on preoperative computed tomography as BMD. RESULTS: Multivariate analysis revealed that low CXI (Hazard ratio [HR], 1.95; 95% confidence interval [CI], 1.25-3.04) and osteopenia (HR, 1.86; 95% CI, 1.19-2.93) were independent prognostic factors for overall survival. Meanwhile, low CXI (HR, 1.58; 95% CI, 1.06-2.34) and osteopenia (HR, 1.57; 95% CI, 1.05-2.36) were also significant prognostic factors for relapse-free survival. A frailty grade combined with CXI and osteopenia stratified into four groups by their prognosis. CONCLUSIONS: Low CXI and osteopenia predict poor survival in patients undergoing esophagectomy for esophageal cancer. Furthermore, a novel frailty grade combined with CXI and osteopenia stratified the patients into four groups according to their prognosis.

Additional Microvascular Anastomosis to Gastric Conduit During Esophagectomy Reduces Anastomotic Leaks: Propensity Score Weighting Study.

BACKGROUND: Impaired gastric conduit perfusion during esophagectomy and reconstruction is considered a key risk factor of anastomotic leaks. The aim of this study is to evaluate the indication and feasibility of additional microvascular anastomosis (AMA) to the gastric conduit in esophageal cancer surgery. PATIENTS AND METHODS: Patients who received an esophagectomy with gastric conduit reconstruction between July 2008 and July 2021 at a single center were reviewed. Patient characteristics, anastomotic viability index (AVI) of the gastric conduit measured with thermal imaging, and operative outcomes were analyzed using Fisher's exact test and Mann-Whitney U test. Two propensity score weighting methods (inverse probability of treatment weighting and overlap weighting) were applied to investigate whether AMA reduces anastomotic leaks. RESULTS: Of the 293 patients who underwent an esophagectomy over the study period, 26 received AMA. AVI in the AMA group was significantly lower than that in the control group (0.64 vs. 0.74, p = 0.026). Overall anastomotic leak rates were 3.8% in the AMA group and 12.4% in the control group. Using two different propensity score weighting methods, the same conclusion was obtained that AMA significantly reduced anastomotic leaks after esophagectomy (both p < 0.001). The logistic regression model for estimating probability of anastomotic leaks provided AVI criteria for AMA application and revealed that AMA significantly reduced the estimated leak rates by a maximum of 49%. CONCLUSIONS: Additional microvascular anastomosis significantly reduced anastomotic leaks after esophagectomy. The proposed AVI criteria for AMA application can help guide surgeons as to when AMA is needed.

Clinical features and management of traumatic ophthalmic artery aneurysm: a case report and literature review.

We report a 52-year-old man with progressive disturbance of visual acuity following a head injury. Magnetic resonance imaging (MRI) showed an aneurysm of the internal carotid artery. Digital subtraction angiography (DSA) 57 days after onset found that the aneurysm originated in the proximal ophthalmic artery. We treated the patient with an intravascular coil embolization, partially filling the aneurysm. Follow-up DSA indicated that the aneurysm did not recur.

Initial medical protocol efforts using both CT and MRI/MRA for acute cerebral infarction.

BACKGROUND: Earlier administration of intravenous recombinant tissue-type plasminogen activator (rtPA) and mechanical thrombectomy (MT) improves the neurological prognosis of patients with acute ischemic stroke (AIS). We introduced a new protocol that includes head and chest computed tomography (CT) and magnetic resonance imaging (MRI)/ magnetic resonance angiography (MRA) for all patients, which is quite different from previously evaluated protocols. This study aimed to examine whether this protocol could contribute to the prompt therapeutic intervention of AIS. METHODS: This is a retrospective observational study analyzing patients with AIS who were transported to our hospital by ambulance between January 2015 and November 2021. An AIS initial treatment protocol was introduced in April 2020, under which, CT and MRI/MRA imaging were performed in all patients, and the indication for rtPA and MT were determined. The participants were divided into those who were treated before and after the protocol introduction (conventional treatment and protocol groups, respectively). The time from hospital arrival to the start of rtPA administration (door-to-needle time: DNT) and the time from hospital arrival to the start of endovascular treatment (door-to-puncture time: DPT) were compared between the groups. RESULT: A total of 121 patients were analyzed, wherein 63 patients received rtPA (18 in the conventional treatment group and 45 in the protocol group) and 98 patients received MT (32 in the conventional treatment group and 66 in the protocol group). The median DNT was 97.0 (IQR 49.0-138.0) min vs. 56.5 (IQR 41.0-72.0) min (p < 0.001) for the conventional treatment and the protocol groups, respectively. The median DPT was 129.0 (IQR 62.0-196.0) min vs. 55.0 (IQR 40.5-69.5) min (p < 0.001), respectively. Moreover, DNT was achieved within 60 min in 5.6% vs. 69.9% (p < 0.001) and DPT within 90 min in 25.0% vs. 85.7% (p < 0.001), respectively. CONCLUSION: The introduction of a protocol, including CT/MRI imaging, significantly shortened DNT and DPT.

Risk Stratification of Postoperative Pneumonia in Patients Undergoing Subtotal Esophagectomy for Esophageal Cancer.

BACKGROUND/AIM: Despite recent progress in surgical techniques and perioperative management, postesophagectomy pneumonia remains the most common complication. Thus, it is important to identify the risk factors of postoperative pneumonia and to improve perioperative management. This study aimed to clarify risk factors for postoperative pneumonia and subsequently stratify the risk of pneumonia. PATIENTS AND METHODS: A total of 154 patients who underwent subtotal esophagectomy were divided into two groups: patients without pneumonia and those with pneumonia. Their backgrounds and operative outcomes were compared. Furthermore, risk factors of postoperative pneumonia were evaluated using a logistic regression model. RESULTS: Postoperative pneumonia developed in 18.8% (n=29) of the study cohort. In the multivariate analysis, the independent risk factors for postoperative pneumonia were forced expiratory volume at 1 s (FEV1) <1.98 l [p=0.011; odds ratio (OR)=3.960; 95% confidence interval (CI)=1.380-11.400], thoracotomy (p=0.043; OR=3.110; 95%CI=1.030-9.320), operative blood loss ≥390 ml (p=0.013; OR=3.900; 95%CI=1.340-11.400), and recurrent laryngeal nerve palsy (RLNP) (p=0.014; OR=3.740; 95%CI=1.310-10.700). Patients were also stratified into the following four groups as per the number of significant risk factors: the incidence of pneumonia in patients with no risk factor, one risk factor, two risk factors, three risk factors were 7.0% (5/71), 13.7% (7/51), 43.5% (10/23), and 77.7% (7/9), respectively. CONCLUSION: FEV1 <1.98 l, thoracotomy, operative blood loss ≥390 ml, and RLNP were independent risk factors of postoperative pneumonia. Additionally, patients could be stratified into four groups according to the incidence of pneumonia.

Embolization of Skull Base Meningiomas with Embosphere Microspheres: Factors Predicting Treatment Response and Evaluation of Complications.

OBJECTIVE: Preoperative embolization for intracranial meningiomas can cause tumor necrosis, reduce intraoperative blood loss, and facilitate surgery. This study aimed to evaluate the efficacy of tumor embolization using Embosphere microspheres for skull base meningiomas and analyze postembolization plain computed tomography (CT) and magnetic resonance imaging (MRI) scans to identify findings that could potentially predict treatment response. METHODS: Between April 2014 and April 2020, 80 patients with skull base meningiomas presenting at our medical center underwent embolization with Embosphere microspheres. The effects of tumor embolization were evaluated through a comparison of postembolization plain CT and contrast-enhanced MRI. RESULTS: A total of 143 vessels (102 of 108 external carotid artery branches and 41 of 65 internal carotid artery branches) from 80 skull base meningiomas were embolized with Embosphere microspheres. Microspheres 100-300 µm in size were used in 2 cases, microspheres 300-500 µm in size were used in 12 cases, and microspheres 500-700 µm in size were used in 66 cases. Postembolization contrast-enhanced MRI showed reductions in enhancing lesions within the tumor in 55 of 80 cases. Postembolization plain CT scans showed high-density lesions within the tumor in 41 of 55 cases. Thus, reductions in enhancing lesions on postembolization contrast-enhanced MRI were statistically significantly associated with the presence of high-density lesions on postembolization plain CT (P < 0.001). Embolization-related neurological complications occurred in 3 cases. CONCLUSIONS: Embosphere microspheres are user friendly and effective embolic materials for the embolization of skull base meningiomas. Postembolization contrast-enhanced MRI and plain CT findings may be useful for evaluating the effects of tumor embolization.

Risk stratification of anastomotic stricture using early postoperative endoscopic and computed tomography findings in patients undergoing esophagectomy with cervical esophagogastric anastomosis for esophageal cancer.

Anastomotic stricture (AS) is one of the major complications after esophagectomy for esophageal cancer. We have previously reported that severe mucosal degeneration (MD) of the anastomotic site was associated with the incidence of AS. Meanwhile, there are few reports to correlate anastomotic internal circumference (AIC) with computed tomography (CT) with the incidence of AS. Therefore, this study was conducted to clarify the correlation of early postoperative endoscopic and CT findings with the incidence of AS. We assessed 205 patients who underwent esophagectomy. We then divided them into the non-AS group (n = 164) and the AS group (n = 41) and compared their background data and intraoperative and postoperative outcomes. We also evaluated the risk factors for AS using logistic regression model. Multivariate analysis revealed small AIC (P = 0.003; OR = 4.400; 95% CI = 1.650-11.700) and severe MD (P < 0.001; OR = 7.200; 95% CI = 2.650-19.600) as the independent risk factors for AS development. We also stratified the patients into the following four groups according to the incidence of AS: low-risk (normal AIC and intact or mild MD, 6.2%), intermediate-risk (small AIC and intact or mild MD, 29.4%), high-risk (normal AIC and severe MD, 42.9%), and very high-risk (small AIC and severe MD, 61.1%). Early postoperative endoscopic and CT findings were useful in predicting the development of AS after esophagectomy.

Laparoscopic definitive surgery for congenital biliary dilatation with aggressive hilar bile ductoplasty and complete resection of the intrapancreatic bile duct in pediatric patients is safe and effective, comparable to open surgery.

BACKGROUND: After surgery for congenital biliary dilatation (CBD), hilar and hepatic bile duct stenosis and intrapancreatic bile duct remnants can cause many postoperative complications. We investigated the efficacy of laparoscopic surgery with aggressive bile ductoplasty and complete excision of the intrapancreatic bile duct in CBD patients compared to open surgery. METHODS: Pediatric patients who underwent surgery for CBD at our institution between 2006 and 2020 were divided into two groups: laparoscopic surgery (Lap group) and open surgery (Op group). Surgical outcomes were compared between the two groups. RESULTS: We enrolled 160 patients (85 in the Lap group and 75 in the Op group). Hilar bile ductoplasty was performed in 52 (61%) patients from the Lap group and 40 (53%) patients from the Op group. The operative time was significantly longer, the amount of blood loss was significantly lower, and the length of hospital stay was significantly shorter in the Lap group than in the Op group. Postoperative early and late complications occurred at a similarly low rate in both groups. When the surgical outcomes were compared between the group who underwent laparoscopic bile ductoplasty and the group that did not, postoperative early and late complications occurred similarly in both groups. CONCLUSIONS: Laparoscopic surgery for CBD with aggressive hilar bile ductoplasty and complete excision of the intrapancreatic bile duct is safe and effective, comparable to open surgery. However, it is necessary to verify whether long-term occurrence of hepatolithiasis similar to open definitive surgery can be obtained in the future.

Experimental Validation of Pullout Resistance for Stent Retrievers and Aspiration Catheters.

Objective: Stretching or avulsion of a small perforating artery caused by mechanical traction contributes to intracranial hemorrhagic complications in mechanical thrombectomy, especially for medium and small-vessel occlusions. This study aimed to measure the pullout resistance during stent retriever (SR) traction and aspiration catheter (AC) traction with or without thrombi and characterize the mechanical properties of each device. Methods: We placed the thrombectomy device in the area corresponding to the insular segment of the middle cerebral artery of a silicon carotid artery model. The thrombectomy device was automatically pulled out at a constant velocity using a horizontal motorized test stand, and pullout resistance was continuously measured 2000 times per second using a digital force gauge. Five types of SRs and two types of ACs with or without thrombus were evaluated. The data were divided into four groups for analysis: SR without clot, SR with clot, AC without clot, and AC with clot. Results: The line graph was a jagged waveform during SR traction, and it was a gentle curve during AC traction. The maximum pullout resistance was higher in the SR with clot group than the other groups. The coefficient of variation was higher in the SR group than the AC group, with or without clot. Conclusion: The pullout resistance during SR traction was more fluctuated than that during AC traction. In the presence of a thrombus, pullout resistance for SR was substantially increased, whereas AC resistance was less susceptible to thrombi. The differences in characteristics may reflect differences in the frequency of mechanical traction injury between the devices during clinical use.

Effect of the postural transition in minimally invasive esophagectomy: a propensity score matching analysis.

BACKGROUND: The advantages of prone position in minimally invasive esophagectomy have not been well studied. This study aimed to investigate the safety and feasibility of a transition from the left lateral decubitus position to the prone position for thoracic procedures in minimally invasive esophagectomy. METHODS: We retrospectively analyzed patients with thoracic esophageal carcinomas who underwent thoracoscopic esophagectomy and laparoscopic gastric mobilization between January 2015 and December 2019. The left decubitus and prone positions were analyzed using propensity score-matched pairs for the baseline characteristics, morbidity, and survival. RESULTS: A total of 114 consecutive patients were included in this study; 90 (78.9%) were male and the median age was 67.2 years old. Of these patients, 39 and 75 underwent left decubitus and prone esophagectomy, respectively. Prone esophagectomy was associated with a lower incidence of pneumonia than that performed in the decubitus position (12.5% vs. 37.5%, p = 0.0187). With respect to the long-term outcomes, there were no significant differences between the 2 groups. The 4-year overall and relapse-free survival rates for prone and decubitus esophagectomy were 73.8% and 73.2%, and 84.4% and 71.8%, respectively (p = 0.9899 and 0.6751, respectively). Prone esophagectomy yielded a shorter operative time (total: 528 [485-579] min vs. 581 [555-610] min, p < 0.0022; thoracic section: 243 [229-271] min vs. 292 [274-309] min, p < 0.0001), less bleeding in the thoracic procedures (0 [0-10] mL vs. 70 [20-138] mL, p < 0.0001), a shorter length of postoperative hospital stay (19 [15-23] vs. 30 [21-46] days, p = 0.0002), and a lower total hospital charge (30,046 [28,175-32,660] US dollars vs. 36,396 [31,533-41,180] US dollars, p < 0.0001). CONCLUSIONS: Transition into the prone position in minimally invasive esophagectomy is feasible with adequate postoperative and oncological safety and economical in esophageal cancer surgery.

Intraoperative nerve monitoring during esophagectomy reduces the risk of recurrent laryngeal nerve palsy.

BACKGROUND: Despite the risk of recurrent laryngeal nerve (RLN) palsy during esophagectomy, no established method of monitoring RLN injury is currently available. METHODS: This study included 187 patients who underwent esophagectomy between 2011 and 2018. Among these, intraoperative nerve monitoring (IONM) was done in 142 patients (IONM group), while the remaining 45 patients underwent conventional surgery without IONM (control group). We investigated the incidence of postoperative complications with regard to the use of IONM. RESULTS: The overall incidence of postoperative RLN palsy was 28% (52/187). The IONM group showed a significantly lower incidence of postoperative RLN palsy as compared to that in the control group (p = 0.004). The overall incidence of postoperative pneumonia was 22% (41/187) in those with Clavien-Dindo (CD) classification beyond grade 2. There were no significant differences between the incidence of any grade of postoperative pneumonia and the use of IONM (p = 0.195 and 0.333; CD > 2 and > 3, respectively). Multivariate analysis demonstrated that tumors in the upper third [odds ratio (OR) 3.12; 95% confidence interval (CI) 1.04-9.29] and lack of IONM use (OR 2.51; 95% CI 1.17-5.38) were independent factors causing postoperative RLN palsy after esophagectomy. CONCLUSION: IONM helps to reduce the risk of postoperative RLN palsy after esophageal cancer surgery.

＜Editors' Choice＞ Long-term outcomes of the partial splenectomy for hypersplenism after portoenterostomy of patients with biliary atresia.

Massive splenomegaly and hypersplenism in patients with biliary atresia after Kasai portoenterostomy were treated with partial splenic embolization or total splenectomy. We performed partial splenectomy to reduce the complications of partial splenic embolization and avoid overwhelming post-splenectomy infection. This study aimed to evaluate the long-term effects of partial splenectomy for hypersplenism on postoperative liver and spleen function in patients with biliary atresia. Among jaundice-free patients with biliary atresia who underwent Kasai portoenterostomy between January 1992 and December 2012, 15 underwent partial splenectomy for massive splenomegaly and hypersplenism at our institution. Changes in the laboratory data 10 years post partial splenectomy were retrospectively investigated, and these along with the latest data were measured. A total of four patients (27%) required living-donor liver transplantation after partial splenectomy, a proportion similar to those who did not undergo partial splenectomy. Compared to the preoperative baseline, the platelet counts were significantly higher at 1 and 3 years after surgery (p < 0.05). Aspartic aminotransferase-to-platelet ratio index was significantly lower at 1, 7, and 10 years after partial splenectomy (p < 0.05). No further surgeries were required for hypersplenism after partial splenectomy over 10 years, and there were no cases of overwhelming post-splenectomy infection after partial splenectomy. Partial splenectomy is safe and effective for the treatment of hypersplenism with biliary atresia over a long time period. It could be considered as an alternative to partial splenic embolization as it can suppress hypersplenism for a long time and induces fewer postoperative complications.

Experimental Observation of Long-Range Magnetic Order in Icosahedral Quasicrystals.

Quasicrystals (QCs), first discovered in 1984, generally do not exhibit long-range magnetic order. Here, we report on long-range magnetic order in the real icosahedral quasicrystals (i QCs) Au-Ga-Gd and Au-Ga-Tb. The Au65Ga20Gd15 i QC exhibits a ferromagnetic transition at TC = 23 K, manifested as a sharp anomaly in both magnetic susceptibility and specific heat measurements, along with an appearance of magnetic Bragg peak below TC. This is the first observation of long-range magnetic order in a real quasicrystal, in contrast to the spin-glass-like behaviors observed for the other magnetic quasicrystals found to date. Moreover, when Gd is replaced by Tb, i.e., for the Au65Ga20Tb15 i QC, a ferromagnetic behavior is still retained with TC = 16 K. Although the sharp anomaly in the specific heat observed for the Au65Ga20Gd15 i QC becomes broadened upon Tb substitution, neutron diffraction experiments clearly show marked development of magnetic Bragg peaks just below TC, indicating long-range magnetic order for the Au65Ga20Tb15 i QC also. Our findings can contribute to the further investigation of exotic magnetic orders formed on real quasiperiodic lattices with unprecedented highest global symmetry, i.e., icosahedral symmetry.

Facilitators and barriers to physicians' entrepreneurial ventures in major Japanese cities: A qualitative study.

BACKGROUND: The Japanese healthcare system currently faces numerous challenges, including a super-aging society and an excessive burden on medical workers; therefore, the need for innovative solutions from healthcare ventures to tackle these issues has increased. Meanwhile, as physicians play important roles in healthcare ventures, the need for Japanese physician entrepreneurs is more important than ever. Given the lack of research examining barriers to physicians starting ventures and what skills, knowledge, and surrounding environments act as facilitators, this study aimed to identify the facilitators and barriers faced by physicians to start ventures. METHODS: Between September and November 2019 and in May 2021, qualitative interviews were conducted with 33 participants, which included eight physician entrepreneurs; two administrative officers at the Ministry of Health, Labour and Welfare and the Ministry of Economy, Trade and Industry; three faculty members at Tokyo Medical and Dental University (in-depth interviews); and 20 medical students (focus group discussions). The interviews were deductively coded based on the social ecological model. The inductive approach was applied to coding any knowledge necessary to start a business. We conducted member checking with three physician entrepreneurs and seven medical students to improve our results' credibility. RESULTS: The factors influencing a physician's decision to launch a new business include their willingness to contribute to society, the unique environment in which an individual is placed while in medical school and afterward, negative aspects of the lack of diversity in physicians' careers, the financial stability provided by a medical license, and self-efficacy. CONCLUSIONS: Our study revealed facilitators and barriers to physicians' entrepreneurial ventures. Knowledge about these factors might be useful in supporting physicians to launch or become involved in healthcare ventures.