Risk factors for pulmonary complications after colorectal cancer surgery: a Japanese multicenter study.

PURPOSE: Pulmonary complications (PC) are a serious condition with a 20% mortality rate. However, few reports have examined risk factors for PC after colorectal surgery. This study investigated the frequency, characteristics, and risk factors for PC after colorectal cancer surgery. METHODS: Between January 2016 and December 2022, we retrospectively reviewed 3979 consecutive patients who underwent colorectal cancer surgery in seven participating hospitals. Patients were divided into patients who experienced PC (PC group, n = 54) and patients who did not (non-PC group, n = 3925). Clinical and pathological features were compared between groups. RESULTS: Fifty-four patients (1.5%) developed PC, of whom 2 patients (3.7%) died due to PC. Age was greater (80 years vs 71 years; p < 0.001), frequency of chronic obstructive pulmonary distress was greater (9.3% vs 3.2%; p = 0.029), performance status was poorer (p < 0.001), the proportion of underweight was higher (42.6% vs 13.4%, p < 0.001), frequency of open surgery was greater (24.1% vs 9.3%; p < 0.001), and blood loss was greater (40 mL vs 22 mL; p < 0.001) in the PC group. Multivariate analysis revealed male sex (odds ratio (OR) 2.165, 95% confidence interval (CI) 1.176-3.986; p = 0.013), greater age (OR 3.180, 95%CI 1.798-5.624; p < 0.001), underweight (OR 3.961, 95%CI 2.210-7.100; p < 0.001), and poorer ASA-PS (OR 3.828, 95%CI 2.144-6.834; p < 0.001) as independent predictors of PC. CONCLUSION: Our study revealed male sex, greater age, underweight, and poorer ASA-PS as factors associated with development of PC, and suggested that pre- and postoperative rehabilitation and pneumonia control measures should be implemented for patients at high risk of PC.

Correlations of age with clinicopathological features, perioperative outcomes and the prognosis in patients with colorectal cancer: a Japanese multicenter study.

PURPOSE: Colorectal cancer is not common in patients under 40 years old, and its associations with clinical features and the prognosis remain uncertain. METHODS: Using a multicenter database, we retrospectively reviewed 3015 patients who underwent colorectal surgery between 2016 and 2021. Patients were divided by age into those < 40 years old (young; n = 52), 40-54 years old (middle-aged; n = 254) and > 54 years old (old; n = 2709). We then investigated age-related differences in clinicopathological features, perioperative outcomes and the prognosis. RESULTS: The proportion of young patients increased annually from 0.63% in 2016 to 2.10% in 2021. Female patients were more frequent, the performance status was better, tumors were larger, clinically node-positive and poorly differentiated adenocarcinomas were more frequent, postoperative complications were less frequent, and the hospital stay was shorter in young patients than in older patients. Young age was an independent predictor of a low risk of postoperative complications (odds ratio, 0.204; 95% confidence interval, 0.049-0.849; p = 0.028). With pathologically node-positive status, adjuvant chemotherapy was more frequent in young patients (100%) than in middle-aged (73.7%) or old (51.8%) patients (p < 0.001), and the 3-year relapse-free survival was better in the young group than in others. CONCLUSION: Despite higher rates of advanced tumors in younger patients, adequate adjuvant chemotherapy appears to improve the relapse-free survival.

Effect of the lymphocyte-to-monocyte ratio on the prognosis of patients with obstructive colorectal cancer with a colonic stent: a retrospective multicenter study in Japan.

PURPOSE: The prognostic value of the lymphocyte-to-monocyte (LMR) ratio has been reported for various cancers, including colorectal cancer (CRC). The insertion of colonic stents is considered effective for patients with surgically indicated obstructive CRC, but their LMR can vary depending on factors such as inflammation associated with stent dilation and improvement of obstructive colitis. However, the usefulness of the LMR in patients with obstructive CRC and colonic stents and the optimal timing for its measurement remain unclear. We conducted this study to investigate the relationship between the pre-stent LMR and the mid-term prognosis of patients with obstructive CRC and stents as a bridge to surgery (BTS). METHODS: The subjects of this retrospective multicenter study were 175 patients with pathological stage 2 or 3 CRC. Patients were divided into a low pre-stent LMR group (n = 87) and a high pre-stent LMR group (n = 83). RESULTS: Only 3-year relapse-free survival differed significantly between the low and high pre-stent LMR groups (39.9% vs. 63.6%, respectively; p = 0.015). The pre-stent LMR represented a prognostic factor for relapse-free survival in multivariate analyses (hazard ratio 2.052, 95% confidence interval 1.242-3.389; p = 0.005), but not for overall survival. CONCLUSIONS: A low pre-stent LMR is a prognostic factor for postoperative recurrence in patients with obstructive CRC and a colonic stent as a BTS.

Long-term outcomes and early recurrence after resection for metachronous pulmonary metastases from colorectal cancer.

PURPOSE: Properly selecting patients for aggressive curative resection for pulmonary metastases (PMs) from colorectal cancer (CRC) is desirable. We purposed to clarify prognostic factors and risk factors for early recurrence after metachronous PM resection. METHODS: Clinical data of 151 patients who underwent R0 resection for metachronous PMs from CRC at two institutions between 2008 and 2021 were reviewed. RESULTS: Seventy-six patients (50.3%) were male, and the median age was 71 (42-91) years. The numbers of colon/rectal cancers were 76/75, with pStage I/II/III/IV/unknown in 15/34/86/13/3. The duration from primary surgery to PM was 19.7 (1.0-106.4) months. The follow-up period was 41.9 (0.3-156.2) months. The 1-, 3-, and 5-year recurrence-free survival (RFS) rates were 75.1%, 53.7%, and 51.1%, and the 1-, 3-, and 5-year overall survival (OS) rates were 97.7%, 87.5%, and 68.2%. On multivariate analysis, lymph node metastasis of the primary lesion (HR 1.683, 95%CI 1.003-2.824, p = 0.049) was an independent predictor of poor RFS, and history of resection for extrapulmonary metastasis (e-PM) (HR 2.328, 95%CI 1.139-4.761, p = 0.021) was an independent predictor of poor OS. Patients who experienced early recurrence (< 6 months) after PM resection showed poorer OS than others (3-year OS 50.8% vs. 90.2%, p = 0.002). On multivariate analysis, e-PM was an independent predictor of early recurrence after PM resection (OR 3.989, 95%CI 1.002-15.885, p = 0.049). CONCLUSION: Since a history of e-PM was a predictor of early recurrence and poor OS after R0 resection for PM, surgical treatment of patients with a history of e-PM should be considered carefully.

Effect of oxaliplatin in elderly colon cancer patients with pathological T4 and/or N2 disease: a multicenter, propensity score-matched analysis.

PURPOSE: Although adjuvant chemotherapy (AC) using fluoro-pyrimidine and oxaliplatin (FU + oxaliplatin) is recommended after curative resection for locally advanced colon cancer patients, several randomized controlled trials have shown no additional effect of oxaliplatin in patients aged ≥ 70 years. Here, we examined the effectiveness of FU + oxaliplatin on the long-term outcome of old patients with a high risk of recurrence. METHODS: This multicenter, retrospective study included 346 colon cancer patients diagnosed with pathological T4 and/or N2 disease from 2016 to 2020. They were divided into an old group (≥ 70 years, n = 197) and a young group (< 70 years, n = 167). Propensity score matching was used to minimize selection bias, and 126 patients per group were matched. RESULTS: Before matching, the rates of poor performance status (p < 0.001) and the presence of comorbidities (76.1% vs. 47.9%, p < 0.001) were higher in the old group. Although all baseline factors were similar between groups, after matching, the AC rate was lower in the old group (45.2% vs. 65.1%, p = 0.002). In the old group, relapse-free (82.2% vs. 55.6% and 69.6%, p < 0.05) and overall survival (83.1% vs. 80.0% and 44.4%, p < 0.05) rates were significantly higher in the AC patients with FU + oxaliplatin than in the AC patients with only FU and the non-AC patients. CONCLUSION: The selected old colon cancer patients with a high risk of recurrence gained an additional benefit with respect to prognosis from FU + oxaliplatin as AC.

Short- and mid-term outcomes of laparoscopic colorectal surgery in patients ≥ 85 years old: a multicenter study using a propensity score-matched analysis.

PURPOSE: The number of laparoscopic surgeries for colorectal cancer (CRC) in elderly patients has been increasing. We examined the short- and mid-term outcomes of laparoscopic surgery for CRC in oldest-old patients (≥ 85 years old) compared with the outcomes in younger patients (< 85 years old). METHODS: We retrospectively reviewed primary tumor resection for CRC from April 2015 to December 2020 at six hospitals. Short- and mid-term outcomes were compared after propensity score matching. RESULTS: From the 1374 patients, 126 matched pairs were selected. In the matched cohort, the duration of postoperative hospital stay was longer in the oldest-old patients than in the younger patients (15 days vs. 12 days, p = 0.001). There were no significant differences between the groups in the rate of Clavien-Dindo grade ≥ 2 postoperative complications (21.4% vs. 15.1%, p = 0.254). The oldest-old patients showed a poorer overall survival (OS) than the younger patients (3-year OS, 79.9% vs. 93.5%, p = 0.005) but comparable recurrence-free survival (RFS) (3-year RFS, 72.2% vs. 81.6%, p = 0.530) and cancer-specific survival rates (CSS) (3-year CSS, 90.1% vs. 99.0%, p = 0.124). CONCLUSION: Laparoscopic surgery for CRC in oldest-old patients was performed safely with comparable short-term outcomes to those in younger patients. Although the OS was poorer in the oldest-old patients than in the younger patients, the oncological mid-term outcomes were comparable. Laparoscopic surgery for CRC can be considered acceptable as a treatment in oldest-old patients.

Improvement of Bobrovsky-Mayor-Wolf-Zakai Bound.

This paper presents a difference-type lower bound for the Bayes risk as a difference-type extension of the Borovkov-Sakhanenko bound. The resulting bound asymptotically improves the Bobrovsky-Mayor-Wolf-Zakai bound which is difference-type extension of the Van Trees bound. Some examples are also given.

Factors related to short-term outcomes and delayed systemic treatment following primary tumor resection for asymptomatic stage IV colorectal cancer.

BACKGROUND: The effectiveness of primary tumor resection (PTR) for asymptomatic stage IV colorectal cancer patients to continue prolonged and safe systemic chemotherapy has recently been re-evaluated. However, postoperative complications lead to a prolonged hospital stay and delay systemic treatment, which could result in a poor oncologic outcome. The objective of this study was to identify the risk factors for morbidity and delay of systemic chemotherapy in such patients. METHODS: Between April 2016 and March 2018, 115 consecutive colorectal cancer patients with distant metastasis who had no clinical symptoms and underwent PTR in all participating hospitals were retrospectively reviewed. The patients were divided into two groups according to the presence (CD ≥ 2, n = 23) or absence (CD < 2, n = 92) of postoperative complications. RESULTS: The proportion of combined resection of adjacent organs was significantly higher in the postoperative complication group (p = 0.014). Complications were significantly correlated with longer hospital stay (p < 0.001) and delay of first postoperative treatment (p = 0.005). Univariate and multivariate analyses showed that combined resection (odds ratio 4.593, p = 0.010) was the independent predictor for postoperative complications. Median survival time was 8.5 months. Postoperative complications were not associated with overall survival, but four patients (3.5%) could not receive systemic chemotherapy because of prolonged postoperative complications. CONCLUSIONS: Although PTR for asymptomatic stage IV CRC patients showed an acceptable prognosis, appropriate patient selection is needed to obtain its true benefit.

The C-reactive protein to albumin ratio predicts postoperative complications in oldest-old patients with colorectal cancer.

PURPOSE: The C-reactive protein to albumin ratio (CAR) is a simple and useful score for predicting the outcomes of patients with various cancers. The aim of this study was to evaluate the CAR and short-term outcomes in oldest-old patients with colorectal cancer. METHODS: A total of 126 patients aged 85 years and older with colorectal cancer who underwent resection for primary colon cancer from April 2015 to December 2018 were included. The preoperative cutoff value of the CAR for predicting postoperative complications was 0.19 on receiver operating characteristic curve analysis. Clinical characteristics and inflammation-based scores were compared between patients with a high CAR (CAR ≥ 0.19, n = 44) and a low CAR (CAR < 0.19, n = 82). RESULTS: A high preoperative CAR level (≥ 0.19) was significantly associated with stoma construction (p = 0.004), blood loss (p = 0.003), postoperative complications (p = 0.016), and systemic inflammation marker levels, including a low neutrophil to lymphocyte ratio (p = 0.006), a low platelet to lymphocyte ratio (p = 0.005), a low prognostic nutritional index (p < 0.001), and a high modified Glasgow prognostic score (p < 0.001). On univariate and multivariate analyses, only the CAR was an independent predictor of postoperative complications (HR 2.864, p = 0.029). CONCLUSIONS: A high CAR was significantly associated with postoperative complications for oldest-old patients with colorectal cancer.

On Default Priors for Robust Bayesian Estimation with Divergences.

This paper presents objective priors for robust Bayesian estimation against outliers based on divergences. The minimum γ-divergence estimator is well-known to work well in estimation against heavy contamination. The robust Bayesian methods by using quasi-posterior distributions based on divergences have been also proposed in recent years. In the objective Bayesian framework, the selection of default prior distributions under such quasi-posterior distributions is an important problem. In this study, we provide some properties of reference and moment matching priors under the quasi-posterior distribution based on the γ-divergence. In particular, we show that the proposed priors are approximately robust under the condition on the contamination distribution without assuming any conditions on the contamination ratio. Some simulation studies are also presented.

Robust Bayesian Regression with Synthetic Posterior Distributions.

Although linear regression models are fundamental tools in statistical science, the estimation results can be sensitive to outliers. While several robust methods have been proposed in frequentist frameworks, statistical inference is not necessarily straightforward. We here propose a Bayesian approach to robust inference on linear regression models using synthetic posterior distributions based on γ-divergence, which enables us to naturally assess the uncertainty of the estimation through the posterior distribution. We also consider the use of shrinkage priors for the regression coefficients to carry out robust Bayesian variable selection and estimation simultaneously. We develop an efficient posterior computation algorithm by adopting the Bayesian bootstrap within Gibbs sampling. The performance of the proposed method is illustrated through simulation studies and applications to famous datasets.

Hydrogen-rich solution attenuates cold ischemia-reperfusion injury in rat liver transplantation.

BACKGROUND: Liver transplantation (LT) is considered the standard treatment for end-stage liver disease, but ideal donors remain in limited supply, resulting in an unavoidable increase in the need to use grafts from marginal donors. The attenuation of ischemia-reperfusion injury (IRI) in such marginal donors is therefore crucial for reducing the possibility of the primary non-function of grafts and graft loss. Some reports have found that molecular-hydrogen showed antioxidant and anti-inflammatory effects in preventing IRI in some non-hepatic transplant models. Therefore, we investigated whether or not molecular-hydrogen could attenuate IRI in LT model rats. METHODS: We used a hydrogen-rich water bath to dissolve hydrogen into solution and graft tissues and performed isogenic and orthotopic LT in Lewis rats with University of Wisconsin (UW) solution. Blood and tissue samples were collected 6 h after the reperfusion. Hepatic enzymes in serum were measured. Pathological findings including the expressions of cytokines and heme oxygenase (HO)-1 in liver tissues were evaluated. RESULTS: The concentration of hydrogen inside the graft tissues increased depending on the storage time, plateauing after 1 h. Serum liver enzyme levels were significantly lower and the histology score of liver damage markedly attenuated in the group given grafts preserved in hydrogen-rich UW solution than in the control group. The hydrogen-rich UW solution group also showed less oxidative damage and hepatocyte apoptosis than the control group, and the expression of proinflammatory cytokines tended to be lower while the protein levels of HO-1 were significantly increased (n = 3-12 per group, P < 0.05). CONCLUSIONS: Storage of liver grafts in hydrogen-rich UW solution resulted in superior functional and morphologic protection against IRI via the up-regulation of HO-1 expression.

Intravital Imaging of Neutrophil Recruitment Reveals the Efficacy of FPR1 Blockade in Hepatic Ischemia-Reperfusion Injury.

Neutrophils are considered responsible for the pathophysiological changes resulting from hepatic ischemia-reperfusion (I/R) injury, which is a complication of trauma, shock, liver resection, and transplantation. Recently, evidence is accumulating that formyl-peptide receptor (FPR) signaling constitutes an important danger signal that guides neutrophils to sites of inflammation. This study aimed to investigate dynamic neutrophil recruitment using two-photon laser-scanning microscopy (TPLSM) in response to FPR1 blockade during hepatic I/R. LysM-eGFP mice were subjected to partial warm hepatic I/R. They were pretreated with an FPR1 antagonist, cyclosporine H (CsH), or formyl peptide, fMLF. Liver was imaged after hepatic laser irradiation or I/R using the TPLSM technique. CsH treatment alleviated hepatic I/R injury, as evidenced by decreased serum transaminase levels, reduced hepatocyte necrosis/apoptosis, and diminished inflammatory cytokine, chemokine, and oxidative stress. In contrast, systemic administration of fMLF showed few effects. Time-lapse TPLSM showed that FPR1 blockade inhibited the accumulation of neutrophils in the necrotic area induced by laser irradiation in vivo. In the CsH-treated I/R group, the number and crawling velocity of neutrophils in the nonperfused area were lower than those in the control group. Meanwhile, FPR1 blockade did not affect monocyte/macrophage recruitment. Hepatic I/R promoted the retention of neutrophils and their active behavior in the spleen, whereas CsH treatment prevented their changes. Intravital TPLSM revealed that formyl-peptide-FPR1 signaling is responsible for regulating neutrophil chemotaxis to allow migration into the necrotic area in hepatic I/R. Our findings suggest effective approaches for elucidating the mechanisms of immune cell responses in hepatic I/R.

Intravital imaging of neutrophil recruitment in intestinal ischemia-reperfusion injury.

BACKGROUND: Neutrophils are known to be key players in innate immunity. Activated neutrophils induce local inflammation, which results in pathophysiologic changes during intestinal ischemia-reperfusion injury (IRI). However, most studies have been based on static assessments, and few have examined real-time intravital neutrophil recruitment. We herein report a method for imaging and evaluating dynamic changes in the neutrophil recruitment in intestinal IRI using two-photon laser scanning microscopy (TPLSM). METHODS: LysM-eGFP mice were subjected to 45 min of warm intestinal ischemia followed by reperfusion. Mice received an intravenous injection of tetramethylrhodamine isothiocyanate-labeled albumin to visualize the microvasculature. Using a time-lapse TPLSM technique, we directly observed the behavior of neutrophils in intestinal IRI. RESULTS: We were able to image all layers of the intestine without invasive surgical stress. At low-magnification, the number of neutrophils per field of view continued to increase for 4 h after reperfusion. High-magnification images revealed the presence or absence of blood circulation. At 0-2 h after reperfusion, rolling and adhesive neutrophils increased along the vasculature. At 2-4 h after reperfusion, the irregularity of crypt architecture and transmigration of neutrophils were observed in the lamina propria. Furthermore, TPLSM imaging revealed the villus height, the diameters of the crypt, and the number of infiltrating neutrophils in the crypt. In the IRI group, the villus height 4 h after reperfusion was significantly shorter than in the control group. CONCLUSIONS: TPLSM imaging revealed the real-time neutrophil recruitment in intestinal IRI. Z-stack imaging was useful for evaluating pathophysiological changes in the intestinal wall.

Recombinant type Human mastadenovirus D85 associated with epidemic keratoconjunctivitis since 2015 in Japan.

The aim of this study was to report the emergence of a recombinant human mastadenovirus (HAdV) type 85 (HAdV-85) and to describe its genomic and clinical characteristics. The strains were detected and identified in Japan in cases of adenoviral conjunctivitis including epidemic keratoconjunctivitis (EKC). The type was designated as HAdV-85 based on the novel combination of penton base (P = HAdV-37), hexon (H = HAdV-19), and fiber (F = HAdV-8). The whole genome sequence determined for HAdV-85 was compared against sequences of other types in the same species. The results of the phylogenetic analysis suggested a recombinant origin between HAdV-53 and HAdV-64, which have been two major causes of adenoviral EKC in Japan over the past decade. During the period between 2008 and 2016 in Kumamoto city, southwest of Japan, 311 cases diagnosed with conjunctivitis were diagnosed as being the consequence of adenoviral infections. Among them, 11 cases were determined to have been caused by HAdV-85 since 2015. Thus, HAdV-85 could be an emerging causative agent of adenoviral conjunctivitis.

Pretransplant trends in α-fetoprotein levels as a predictor of recurrence after living donor liver transplantation for unresectable hepatoblastoma: A single-institution experience.

LT is a practical therapeutic alternative for unresectable hepatoblastoma; however, deciding when to perform LT is difficult. The aim of this study was to optimize the timing of LT for hepatoblastoma using pretransplant trends in AFP levels. Trends in pretransplant AFP levels and their influence on post-transplant outcomes were retrospectively evaluated. All patients who underwent living donor LT for hepatoblastoma in our institution since 2002 were included. Variables analyzed included history of prior tumor resection, pretransplant AFP responses to chemotherapy, metastatic disease at diagnosis, and post-transplant chemotherapy. Eight patients (seven boys and one girl; median age, 35 months; range, 15 months-12 years) were transplanted. The overall post-transplant recurrence-free survival rate was 62.5% (5/8) with a mean follow-up of 77 months. Patients with post-transplant recurrence showed a 0.573 log increase in AFP levels after the last chemotherapy session before LT. This was significantly higher than the 0.279 log decrease observed in patients without post-transplant recurrence (P = .024). Because the AFP response cannot be accurately predicted before each cycle of chemotherapy, it may be appropriate to perform LT when AFP levels do not decrease after the last cycle and before they are found to be elevated again.

[Granuloma by Foreign Body Reaction to the Stapler Used for Partial Resection of the Lung].

A 66-year-old woman underwent right lower lobectomy and partial resection of the middle lobe for Stage I A double lung cancer. Five years after the operation, a routine computed tomography (CT) scan showed a mass on the staple line at the middle lobe. The mass was enlarged on CT scan after 6 months. A definitive diagnosis could not be made by bronchoscopic examination and fluoro-2-deoxy-glucose(FDG)/positron emission tomography( PET)-CT showed FDG uptake in the mass( early phase:SUVmax=3.24, late phase:SUVmax=4.31). Local recurrence of lung cancer was not completely denied, and right middle lobectomy was performed. Histopathologically, the resected specimen revealed granuloma with foreign body reaction. We should keep in mind the possibility of granuloma as differential diagnosis of lung cancer when using stapler.

A case of pancreaticoduodenal artery bleeding after laparoscopic right colectomy requiring open hemostasis.

BACKGROUND: Pancreatic and duodenal-related complications after right colectomy carry a higher risk of mortality. CASE PRESENTATION: A 64-year-old woman underwent laparoscopic right colectomy for a laterally spreading tumor in the cecum. On postoperative day 10, she experienced sudden hematemesis. Contrast-enhanced computed tomography (CT) of the abdomen showed a large amount of hemorrhage in the stomach, but no obvious extravasation. In addition, free air was observed near the duodenal bulb. Despite blood transfusion, vital signs remained unstable and emergency surgery was performed. The abdomen was opened through midline incisions in the upper and lower abdomen. A fragile wall and perforation were observed at the border of the left side of the duodenal bulb and pancreas, with active bleeding observed from inside. As visualization of the bleeding point proved difficult, the duodenum was divided circumferentially to confirm the bleeding point and hemostasis was performed using 4-0 PDS. The left posterior wall of the duodenum was missing, exposing the pancreatic head. For reconstruction, the jejunum was elevated via the posterior colonic route and the duodenal segment and elevated jejunum were anastomosed in an end-to-side manner. Subsequently, gastrojejunal and Brown anastomoses were added. Drains were placed before and after the duodenojejunal anastomosis. Postoperative vital signs were stable and the patient was extubated on postoperative day 1. Follow-up contrast-enhanced CT of the abdomen showed no active bleeding, and the patient was discharged home on postoperative day 21. As of 6 months postoperatively, the course of recovery has been uneventful. CONCLUSIONS: We encountered a case of pancreaticoduodenal artery hemorrhage after laparoscopic right colectomy. Bleeding at this site can prove fatal, so treatment plans should be formulated according to the urgency of the situation.

Monte carlo simulation study on the dose and dose-averaged linear energy transfer distributions in carbon ion radiotherapy.

Dose-averaged linear energy transfer (LETd) is conventionally evaluated from the relative biological effectiveness (RBE)-LETd fitted function used in the treatment planning system. In this study, we calculated the physical doses and their linear energy transfer (LET) distributions for patterns of typical CIRT beams using Monte Carlo (MC) simulation. The LETd was then deduced from the MC simulation and compared with that obtained from the conventional method. The two types of LETd agreed well with each other, except around the distal end of the spread-out Bragg peak. Furthermore, an MC simulation was conducted with the material composition of water and realistic materials. The profiles of physical dose and LETd were in good agreement for both techniques. These results indicate that the previous studies to analyze the minimum LETd in CIRT cases are valid for practical situations, and the material composition conversion to water little affects the dose distribution in the irradiation field.

Intestinal Behçet's and suspected intestinal Behçet's disease: a report of four surgical cases.

BACKGROUND: Intestinal Behçet's disease (BD) is often associated with ulceration that requires surgery, including perforation and abscess formation. However, no consensus has been reached on the optimal extent of resection or treatment strategy. This study reviewed four cases of intestinal or suspected intestinal BD. CASE PRESENTATIONS: In Case 1, a 74-year-old woman diagnosed with BD 2 years earlier was treated with anti-tumor necrosis factor α antibody (Infliximab) and steroids. She had oral and pubic ulcers. After close investigation of abdominal pain, perforation of the gastrointestinal tract was suspected and surgery was performed. Multiple perforating ulcers and abscesses were found in the distal ileum, and the small intestine was resected. Postoperatively, the patient was treated with an increased steroid dose and symptoms have remained stable. Case 2 involved a 69-year-old woman with oral and pubic ulcers, ocular ulcer, and skin lesions. She experienced sudden onset of abdominal pain during treatment for lymphoma. She showed multiple perforating ulcers throughout the ileum and underwent resection of the small intestine and ileostomy. Upper abdominal pain appeared during postoperative treatment for high-output syndrome. The patient underwent omentoplasty after perforation of the upper gastrointestinal tract was diagnosed. Postoperatively, anti-interleukin-1 beta antibodies (canakinumab) was administered to control the disease. Case 3 involved an 81-year-old, previously healthy woman. She presented to her previous physician with complaints of pubic ulcer, hemorrhage and abdominal pain. Colonoscopy showed multiple ulcers throughout the entire colon. Steroid therapy was started, but bleeding proved difficult to control and total proctocolectomy was performed. Histopathology revealed multiple perforating ulcers and BD was diagnosed. Postoperatively, the patient remains under steroid control. Case 4 involved a 43-year-old man with abdominal pain who showed abscess formation in the ileocecal region. After excision of the ileocecal area, multiple ulcers were diagnosed. Two years later, abdominal pain recurred and free air was found in the abdomen on close imaging. Emergency anastomotic resection was performed due to ulceration and perforation of the anastomosis. CONCLUSIONS: Intestinal BD may flare up after surgical treatment and require multiple surgeries. Introducing pharmacotherapy as soon as possible after surgical treatment is important to control the disease.