Change in antimicrobial susceptibility of pathogens isolated from surgical site infections over the past decade in Japanese nation-wide surveillance study.

Inappropriate antimicrobial therapy for surgical site infections (SSIs) can lead to poor outcomes and an increased risk of antibiotic resistance. A nationwide survey was conducted in Japan from 2018 to 2019 to investigate the antimicrobial susceptibility of pathogens isolated from SSIs. The data were compared with those obtained in 2010 and 2014-2015 surveillance studies. Although the rate of detection of extended-spectrum ß-lactamase producing strains of Escherichia coli was increased from 9.5% in 2010 to 23% in 2014-2015, the incidence decreased to 8.7% in 2018-2019. Although high susceptibility rates were detected to piperacillin/tazobactam (TAZ), the geometric mean MICs were substantially higher than to meropenem (2.67 vs 0.08 µg/mL). By contrast, relatively low geometric mean MICs (0.397 µg/mL) were demonstrated for ceftolozane/TAZ. Although the MRSA incidence rate decreased from 72% in the first surveillance to 53% in the second, no further decrease was detected in 2018-2019. For the Bacteroides fragilis group species, low levels of susceptibility were observed for moxifloxacin (65.3%), cefoxitin (65.3%), and clindamycin (CLDM) (38.9%). In particular, low susceptibility against cefoxitin was demonstrated in non-fragilis Bacteroides, especially B. thetaiotaomicron. By contrast, low susceptibility rates against CLDM were demonstrated in both B. fragilis and non-fragilis Bacteroides species, and a steady decrease in susceptibility throughout was observed (59.3% in 2010, 46.9% in 2014-2015, and 38.9% in 2018-2019). In conclusion, Japanese surveillance data revealed no significant lowering of antibiotic susceptibility over the past decade in organisms commonly associated from SSIs, with the exception of the B. fragilis group.

A Preoperative Scoring System to Predict Carcinoma in Patients with Gallbladder Polyps.

INTRODUCTION: A preoperative scoring system to predict carcinoma in patients with gallbladder polyps (GBPs). METHODS: Preoperative parameters of patients with GBPs who underwent cholecystectomies were used to construct a scoring system to ascertain the risk of malignancy (reference group). The scoring system developed from this approach was applied to the validation group. RESULTS: In the reference group, 11.5% of patients had carcinomas, in whom the median age was 68 years and the polyp size was 16.9 mm. According to the univariate analysis, the significant factors for carcinoma were age ≥65 years, the presence of gallstones, polyp size ≥13 mm, solitary polyp, and sessile polyp. Age ≥65 years and polyp size ≥13 mm were significant factors according to the multivariate analysis. From these results, we developed a preoperative scoring system to predict carcinoma. The patients were divided into 1 of 2 groups: low-risk and high-risk and their malignancy rates were 4.1 and 61.1% respectively (p < 0.001). In the validation group, the malignancy rate was higher for those in the high-risk group (p = 0.016). CONCLUSIONS: The proposed preoperative scoring system based on simple clinical variables appears to be useful for predicting malignancy in patients with GBPs.

Severe esophagitis associated with cytomegalovirus during concurrent chemoradiotherapy for esophageal cancer.

Although radiation esophagitis is one of the most common adverse events that occurs during chemoradiotherapy (CRT) in patients with esophageal cancer, CRT-associated cytomegalovirus (CMV) esophagitis is rare. CMV esophagitis typically occurs in patients with an immunosuppressed status. Here we report a case of CMV esophagitis during CRT initially treated as radiation esophagitis. A 64-year-old man with mid-thoracic esophageal cancer was admitted to our hospital with clinical stage cT4bN1M1 (supraclavicular lymph node metastasis) Stage IV according to the UICC ver. 7 guidelines, and he was administered definitive concurrent CRT. From the 39th day of CRT onwards, he presented with a sustained fever and severe odynophagia that was resistant to antibiotic therapy. An esophagoscopy revealed severe esophagitis with a circumferential ulcer throughout the entire esophagus, and CMV esophagitis was clinically suspected because of positive result of CMV antigenemia. Subsequently, antiviral therapy for CMV provided dramatic relief of his symptoms. Later, CMV DNA was confirmed with a polymerase chain reaction in the biopsy specimen.The symptoms of CMV esophagitis resemble those of radiation esophagitis and can make the diagnosis difficult. Thus, CMV esophagitis associated CRT may be overlooked or masked by radiation esophagitis and can cause a delay in healing. Therefore, CMV esophagitis may be considered when severe intractable esophagitis is observed during CRT.

Identification of a predictive factor for distant metastasis in esophageal squamous cell carcinoma after definitive chemoradiotherapy.

BACKGROUND AND PURPOSE: Distant metastasis (DM) after definitive chemoradiotherapy has not been a focus of research in esophageal carcinoma. At present, local-regional control is improving following advances in salvage treatments after definitive chemoradiotherapy. There is a need to focus on suppressing the development of DM. The aim of this study was to identify pre-treatment factors associated with DM after definitive chemoradiotherapy. MATERIALS AND METHODS: This study included 144 patients with thoracic esophageal squamous cell carcinoma (Stage I/II/III/IV; 35/17/69/23) (TNM 7th) who underwent definitive chemoradiotherapy; >50 Gy was prescribed to all gross tumors with concurrent administration of 5-fluorouracil ± platinum. Pre-treatment factors included age, gender, performance status, tumor location, T/N/M status, tumor length, size of metastatic lymph nodes (LN size), and the presence of intramural metastasis or multiple primary tumors. The effects of pre-treatment factors on overall survival (OS) and DM were evaluated. RESULTS: The median follow-up period was 48 months. DM occurred as an initial progression in 21 % of patients, and LN size correlated with DM development (hazard ratio [HR] = 5.12; p = 0.0013) and poor OS (HR = 2.20; p = 0.0076) in univariate and multivariate analyses. CONCLUSIONS: LN size is a quantitative pre-treatment prognostic factor that should be assessed prior to definitive chemoradiotherapy. Patients with large metastatic lymph nodes are at high risk of DM and should be monitored.

Influence of matrix attachment installation load on movement and resultant forces in implant overdentures.

PURPOSE: This in vitro study investigated the effect of attachment installation conditions on the load transfer and denture movements of implant overdentures, and aims to clarify the differences among the three types of attachments, namely ball, Locator, and magnet attachments. MATERIALS AND METHODS: Three types of attachments, namely ball, Locator, and magnetic attachments were used. An acrylic resin mandibular edentulous model with two implants placed in the bilateral canine regions and removable overdenture were prepared. The two implants and bilateral molar ridges were connected to three-axis load-cell transducers, and a universal testing machine was used to apply a 50 N vertical force to each site of the occlusal table in the first molar region. The denture movement was measured using a G(2) motion sensor. Three installation conditions, namely, the application of 0, 50, and 100 N loads were used to install each attachment on the denture base. The load transfer and denture movement were then evaluated. RESULTS: The resultant force decreased with increasing installation load for all attachments. In particular, the resultant force on implants on the loading side of the Locator attachment significantly decreased when the installation load was increased from 0 to 50 N, and that for magnetic attachment significantly decreased when the installation load was increased from 50 to 100 N. For the residual ridges on the loading side, the direction of the forces for all attachments changed to downward with increasing installation load. Furthermore, the yaw Euler angle increased with increasing installation load for the magnetic attachment. CONCLUSIONS: Subject to the limitations of this study, the use of any installation load greater than 0 N is recommended for the installation of ball and Locator attachments on a denture base. Regarding magnetic attachments, our results also recommend installation on a denture base using any installation load greater than 0 N, and suggest that the resultant force acting on the implant can be decreased by increasing the installation load; however, a large installation load of 100 N should be avoided when installing the attachment on the denture base to avoid increasing the denture movement.

Prognostic significance of receptor for advanced glycation end products expression in hepatocellular carcinoma after hepatectomy.

BACKGROUND: The receptor for advanced glycation end products (RAGE) is recognized to be responsible for cancer progression in several human cancers. In this study, we investigated the clinical impact of RAGE expression in patients with hepatocellular carcinoma (HCC) after hepatectomy. MATERIALS AND METHODS: Sixty-five consecutive patients who underwent initial hepatectomy for HCC were investigated. The relationships between immunohistochemical expression of RAGE and clinicopathologic features, clinical outcome (overall survival [OS], and disease-free survival [DFS]) were evaluated. RESULTS: The cytoplasmic expression of RAGE in HCC cells was observed in 46 patients (70.8%) and correlated with histologic grade (poorly differentiated versus moderately differentiated HCC, P = 0.021). Five-year OS in RAGE-positive and RAGE-negative groups were 72% and 94%, respectively, whereas 5-y DFS were 29% and 55%, respectively. There were significant differences between OS and DFS (P = 0.018 and 0.031, respectively). Multivariate analysis indicated that RAGE was an independent predictor for both OS and DFS (P = 0.048 and 0.032, respectively). CONCLUSIONS: Our data suggest for the first time a positive correlation between RAGE expression and poor therapeutic outcome. Furthermore, RAGE downregulation may provide a novel therapeutic target for HCC.

Do sensation differences exist between dental implants and natural teeth?: a meta-analysis.

OBJECTIVE: The purpose of this systematic review was to survey evidence pertaining to the sensation differences between natural teeth and osseointegrated dental implants. MATERIAL AND METHODS: Using the MEDLINE (online PubMed) database, Cochrane Library, and Scientific Citation index, we performed a systematic search of articles. We used the following search terms: "perception or sensation and dental implant." The systematic review of the extracted articles was performed to see the sensation differences between natural teeth and dental implants. RESULTS: A total of six studies on oral sensation, "tactile sensibility," and "thickness discrimination" were included in the meta-analysis. As to the "tactile sensibility", all studies indicated the threshold levels of the implants were about 4-20 times higher than that of natural teeth. The tactile sensibility of an implant was significantly higher than that of a natural tooth, with an standardized mean difference (SMD) of 8.3619 (95% CI, 6.3920-10.3317) and a P < 0.0001. As to the "thickness discrimination", all studies indicated the threshold levels of implants were about 1.2-2.3 times higher than that of natural teeth. The thickness discrimination was significantly higher than that of natural teeth with an SMD of 1.2368 (95% CI, 0.8699-1.6038) and a P < 0.0001. CONCLUSION: This meta-analysis suggested that both tactile sensibility and thickness discrimination thresholds of implants were significantly higher than those of natural teeth. This meta-analysis reconfirms that sensation differences between dental implants and natural teeth exist.

Combined hepatocellular-cholangiocarcinoma producing parathyroid hormone-related protein: report of a case.

Combined hepatocellular-cholangiocarcinoma (CHCC) is an uncommon form of primary liver cancer. A 57-year-old man was readmitted to our hospital for treatment of recurrent CHCC, 12 months after central bisegmentectomy and 4 months after limited hepatic resection. Magnetic resonance imaging (MRI) revealed multiple hepatic nodules. Laboratory data showed increased serum levels of α-fetoprotein (AFP), calcium, and parathyroid hormone-related protein (PTH-rP), to 5,571 ng/mL, 17.0 mg/dL, and 16.1 pmol/L, respectively. Palliative mass reduction surgery was indicated by the fact that the hypercalcemia was difficult to manage medically. Thus, we performed lateral segmentectomy with partial resection of segment 7 and the caudate lobe, and microwave coagulation therapy for multiple recurrent CHCC. Thereafter, the serum PTH-rP and AFP levels decreased remarkably and the hypercalcemia was controlled for the next 3 months. He died of disease progression 9 months after the last hepatic surgery. To our knowledge, this is only the second reported case of CHCC producing PTH-rP in the English-language literature.

Dosimetric advantages of O-ring design radiotherapy system for skull-base tumors.

The purpose of this study was to investigate whether a new O-ring design radiotherapy delivery system has advantages in radiotherapy planning for skull-base tumors. Twenty-five patients with skull-base tumors were included in this study. Two plans were made using conventional (Plan A) or new (Plan B) techniques. Plan A consisted of four dynamic conformal arcs (DCAs): two were horizontal, and the other two were from cranial directions. Plan B was created by converting horizontal arcs to those from caudal directions making use of the O-ring design radiotherapy system. The micromultileaf collimators were fitted to cover at least 99% of the planning target volume with prescribed doses, 90% of the dose at the isocenter. The two plans were compared in terms of target homogeneity, conformity, and irradiated volume of normal tissues, using a two-sided paired t-test. For evaluation regarding target coverage, the homogeneity indices defined by the International Commission on Radiation Units and Measurements 83 were 0.099 ± 0.010 (mean ± standard deviation) and 0.092 ± 0.010, the conformity indices defined by the Radiation Therapy Oncology Group were 1.720 ± 0.249 and 1.675 ± 0.239, and the Paddick's conformity indices were 0.585 ± 0.078 and 0.602 ± 0.080, in Plans A and B, respectively. For evaluation of irradiated normal tissue, the Paddick's gradient indices were 3.118 ± 0.283 and 2.938 ± 0.263 in Plans A and B, respectively. All of these differences were statistically significant (p-values < 0.05). The mean doses of optic nerves, eyes, brainstem, and hippocampi were also significantly lower in Plan B. The DCA technique from caudal directions using the new O-ring design radiotherapy system can improve target homogeneity and conformity compared with conventional DCA techniques, and can also decrease the volume of surrounding normal tissues that receives moderate doses.

Development of silicon-on-insulator direct electron detector with analog memories in pixels for sub-microsecond imaging.

We have developed a high-speed recordable direct electron detector based on silicon-on-insulator technology. The detector has sixteen analog memories in each pixel to record sixteen images with sub-microsecond temporal resolution. A dedicated data acquisition system has also been developed to display and record the results on a personal computer. The performance of the direct electron detector as an image sensor is evaluated under electron irradiation with an energy of 30 keV in a low-voltage transmission electron microscope equipped with a photocathode electron gun. We demonstrate that the detector can record images at an exposure time of 100 ns and an interval of 900 ns.

Postoperative peripheral blood monocyte count correlates with postoperative bile leakage in patients with colorectal liver metastases after hepatic resection.

PURPOSE: Postoperative bile leakage is one of the most common complications after hepatic surgery. The relationship between the inflammatory response and postoperative bile leakage has not been fully investigated. Therefore, we retrospectively investigated the relation between postoperative peripheral blood monocyte count and bile leakage in patients with colorectal liver metastases (CRLM) after elective hepatic resection. METHODS: The study comprised 105 patients who had undergone hepatic resection for CRLM between January 2000 and March 2012. Perioperative risk factors pertinent to development of bile leakage were investigated using univariate and multivariate analyses. RESULTS: Bile leakage developed in 9 (8.6 %) of 105 patients. In multivariate analysis, intraoperative fresh frozen plasma (FFP) transfusion (p = 0.009) and lower monocyte count of the peripheral blood on postoperative day 1 (p = 0.038) were found as independent risk factors of bile leakage. CONCLUSIONS: Postoperative lower monocyte count and intraoperative FFP transfusion were associated with the development of postoperative bile leakage after elective hepatic resection in patients with CRLM.

Practice to extend indication of hepatic resection for colorectal liver metastasis.

BACKGROUND/AIMS: Recent reports have demonstrated that patients with limited extrahepatic disease and bilobar disease can benefit from aggressive surgical resection in combination with chemotherapy. Therefore, we extended indication of hepatic resection for colorectal liver metastasis (CRLM) since 2004. In this report, we retrospectively assessed changes in our therapeutic strategy for CRLM. METHODOLOGY: The subjects were 67 patients who underwent hepatic resection for CRLM between January 2000 and December 2008. Patients were classified into two groups; early period (2000-2003) and late period(2004-2008). We assessed prognostic factors and change in our hepatic resection policy on operative indication for CRLM in relation to therapeutic outcome. RESULTS: In multivariate analysis, more than 4 lymph node metastases (p=0.0277) and bilobar disease (p=0.0142) were significant predictors of disease- free survival, while significant predictor of overall survival were more than four lymph node metastases (p=0.0014) and bilobar disease (p=0.0392). Bilobar disease and presence of extrahepatic disease were significantly greater in late period. However, incidence of postoperative complications, disease-free and overall survivals in both periods were comparable. CONCLUSIONS: Practice to extend indication of hepatic resection for patients with advanced CRLM seems to increase the respectability rate without increasing morbidity and mortality, whenever a macroscopically curative resection with acceptable operative risk was thought possible.

Comparison of hepatocellular carcinoma with cirrhosis patients undergoing hepatic resection between hepatitis B and C infection.

BACKGROUND/AIMS: Type B and C hepatic cirrhosis are main causes of hepatocellular carcinoma (HCC). In resected cases of HCC, residual liver function of type B cirrhotic patients tend to be better compared to type C cirrhotic patients. We compared clinical data of patients with type B hepatic cirrhosis with type C hepatic cirrhosis who underwent hepatic resection for HCC. METHODOLOGY: Subjects were 16 patients with type B hepatic cirrhosis and 20 patients with type C hepatic cirrhosis who underwent hepatic resection for HCC at Jikei University Hospital. Perioperative findings including age, gender, preoperative laboratory data including ICGR15, Child's classification, model for end-stage liver disease (MELD) score, tumor factor, type of resection, duration of operation, blood loss and incidence of post-operative complications, as well as disease-free and overall survival were analyzed. RESULTS: In type B cirrhotic patients, the age was younger (p<0.001), pre-operative ICGR15 (p=0.004), hemoglobin (p=0.032), albumin (p=0.006), Child's classification (p=0.008), and MELD score (p=0.011) were better, and incidence of postoperative pulmonary complications were fewer (p=0.039) than type C cirrhotic patients. Preoperative ICG, in 11 of 16 type B cirrhotic patients were normal (<10%). CONCLUSIONS: Residual liver function of type B cirrhotic patients were better than type C cirrhotic patients.

Practice to minimize the use of blood products improve outcome after hepatic resection for hepatocellular carcinoma.

BACKGROUND/AIMS: Because recent studies have reported that allogenic blood transfusion exerts negative immunomodulatory effects, we tried decreasing the use of blood products in perioperative management of hepatic resection since 2003. We retrospectively assessed the changes in our blood transfusion policy on hepatic resection for hepatocellular carcinoma (HCC). METHODOLOGY: Subjects were 78 patients who underwent hepatic resection for HCC at Jikei University Hospital. Patients were classified into 2 groups; early period (2000-2002, n=25), and late period (2003-2006, n=53). Perioperative findings including age, gender, hepatitis virus, preoperative ICGR15, Child's classification, tumor factor, type of resection, duration of operation, blood loss, the amount of peri-operative red cell concentration (RC) and fresh frozen plasma (FFP) transfusion, incidences of post-operative complication, as well as disease-free and overall survival were analyzed. RESULTS: The amount of perioperative RC (p=0.041) and FFP (p<0.001) transfusion in late period were significantly smaller and non-anatomical limited partial resection (p=0.004) in late period was greater than early period. The patients in late period had significantly better overall survival rate than those in early period (p<0.001). CONCLUSIONS: Practice to minimize the use of blood products may improve patient's survival after hepatic resection for HCC.

2-methacryloyloxyethyl phosphorylcholine polymer treatment prevents Candida albicans biofilm formation on acrylic resin.

PURPOSE: We aimed to evaluate the effectiveness of photoreactive 2-methacryloyloxyethyl phosphorylcholine (MPC) in inhibiting Candida albicans biofilm formation on polymethyl methacrylate (PMMA) and assess its mechanism and need for re-application by evaluating its interaction with salivary mucin and durability during temperature changes. METHODS: PMMA discs were used as specimens. The MPC coating was applied using the spray and cure technique for the treatment groups, whereas no coating was applied to the control. The MPC treatment (MT) groups were further differentiated based on the number of thermal cycles involved (0, 1000, 2500, and 5000). The optical density was measured to assess mucin adsorption (MA). Contact angle (CA) was calculated to evaluate surface hydrophilicity. The presence of MPC components on the PMMA surface was assessed using X-ray photoelectron spectroscopy (XPS). C. albicans biofilms were evaluated qualitatively (scanning electron microscope images) and quantitatively (colony-forming units (CFUs)). Statistical analysis was conducted using two-way analysis of variance and Tukey's multiple comparison test. RESULTS: MA rate and CA increased significantly in the MT groups, which exhibited significantly fewer CFUs and thinner biofilms than those of the control group. Based on the XPS, MA, and CFU evaluations, the durability and efficacy of the MPC coating were considered stable up to 2500 thermal cycles. Additionally, a significant interaction was observed between mucin concentration and MPC efficacy. CONCLUSIONS: The photoreactive MPC coating, which was resistant to temperature changes for approximately 3 months, effectively prevented C. albicans biofilm formation by modifying surface hydrophilicity and increasing mucin adsorption.

Perioperative change in peripheral blood monocyte count may predict prognosis in patients with colorectal liver metastasis after hepatic resection.

BACKGROUND: Prognostic value of perioperative change in peripheral blood leukocyte subset count of cancer patients have not been fully investigated. Therefore, we retrospectively investigated the relation between perioperative change in peripheral blood monocyte count and disease-free as well as overall survival after hepatic resection for colorectal liver metastasis (CRLM). METHODS: The subjects were 64 patients who underwent hepatic resection for CRLM between January 2000 and December 2008. We retrospectively investigated the relation between perioperative change in peripheral blood monocyte count and disease-free as well as overall survival. RESULTS: In multivariate analysis, more than four lymph node metastases (P = 0.0298) and extrahepatic disease (P = 0.0423) were significant predictors of disease-free survival, while significant predictor of overall survival were more than four lymph node metastases (P = 0.0011), bilobar disease (P = 0.0024), and increase in perioperative monocyte less than twice (P = 0.0029). Morover, increase in perioperative monocyte of less than twice positively correlated with intraoperative blood transfusion. CONCLUSIONS: Perioperative change in peripheral blood monocyte count is an independent risk factor for overall survival after hepatic resection for CRLM, and may reflect immunosuppressive state.

Intra-hepatic arterioportal shunt mimicking a metastatic liver tumor: report of a case.

The differential diagnosis of an arterioportal shunt (APS) is difficult and important. We report a case of an intra-hepatic APS mimicking a metastatic liver tumor on imaging scans in a patient without hepatic cirrhosis. The patient was a 64-year-old woman, who had undergone low anterior resection of the rectum for advanced rectal cancer, followed 2 months later by right hemihepatectomy, including the middle hepatic vein, for a synchronous metastatic liver tumor. About 2 years after the hepatectomy, a follow-up CT scan showed a new mass in the remnant liver, suggestive of a metastatic liver tumor, the assumption of which was further supported by an elevated serum carcinoembryonic antigen (CEA) level. However, the findings of magnetic resonance imaging were not consistent with a malignant tumor, and Doppler ultrasonography showed a low echoic area connected with the portal vein branch and the hepatic artery branch. Thus, we diagnosed intra-hepatic APS. The patient remains well without signs of growth of the hepatic lesion, although with fluctuating serum CEA levels.

Association of volumetric-modulated arc therapy with radiation pneumonitis in thoracic esophageal cancer.

The lung volume receiving low-dose irradiation has been reported to increase in volumetric-modulated arc radiotherapy (VMAT) compared with three-dimensional conformal radiotherapy (3DCRT) for thoracic esophageal cancer, which raises concerns regarding radiation pneumonitis (RP) risk. This single institutional retrospective cohort study aimed to explore whether VMAT for thoracic esophageal cancer was associated with RP. Our study included 161 patients with thoracic esophageal cancer, of whom 142 were definitively treated with 3DCRT and 39 were treated with VMAT between 2008 and 2018. Radiotherapy details, dose-volume metrics, reported RP risk factors and RP incidence were collected. The RP risk factors were assessed via multivariate analysis. Dose-volume analysis showed that VMAT delivered more conformal dose distributions to the target volume (P < 0.001) and reduced V30 Gy of heart (57% vs 41%, P < 0.001) but increased V5 Gy (54% vs 41%, P < 0.001) and V20 Gy (20% vs 17%, P = 0.01) of lungs compared with 3DCRT. However, the 1-year incidence rates of RP did not differ between the two techniques (11.3% in 3DCRT vs 7.7% in VMAT, P = 0.53). The multivariate analysis suggested that the presence of interstitial lung disease (ILD) (P = 0.01) and V20 Gy of lungs ≥20% (P = 0.008) were associated with RP. Conclusively, VMAT increased the lung volume receiving low to middle doses irradiation, although this might not be associated with RP. Further studies are needed to investigate the effect of using VMAT for delivering conformal dose distributions on RP.

Novel Magnetic Attachment System Manufactured Using High-Frequency Heat Treatment and Stamp Technique: Introduction and Basic Performance.

Recently, a novel magnetic attachment with extremely low cost and high performance was developed. This article aims to introduce a novel magnetic attachment and to evaluate its basic eligibility for denture retention in clinical practice. The novel magnetic attachment system used in this study was the direct-bonding root-keeper-type Magteeth™ MT800 (MagneDesign, Nagoya, Japan). The retentive force without displacement (position 0) and after horizontal displacement to positions 0.5, 1, 1.5, 2, 2.5, and 3 mm were measured. The values relative to the retentive force without displacement were gradually decreased to 82.7 ± 16.3%, 68.8 ± 17.1%, 62.4 ± 15%, 47.2 ± 13.1%, 35.7 ± 9.9%, and 20.7 ± 6.5%, respectively. The retentive force and magnetic field strength did not change significantly after the load test (100 N load, 10,000 times). No new gap between the metal and resin was found in the root keeper- and magnet assembly-embedded blocks after the load test. Some scratches on magnetic assembly and root keeper surface, while no change in the resin texture after the load test were observed. Based on the findings of this preliminary study, this novel low-cost magnetic attachment exhibited favorable retention, strength, and durability for clinical use.

Preoperative chemoradiotherapy for locally advanced low rectal cancer using intensity-modulated radiotherapy to spare the intestines: a single-institutional pilot trial.

The irradiated volume of intestines is associated with gastrointestinal toxicity in preoperative chemoradiotherapy for rectal cancer. The current trial prospectively explored how much of the irradiated volume of intestines was reduced by intensity-modulated radiotherapy (IMRT) compared with 3-dimensional conformal radiotherapy (3DCRT) and whether IMRT might alleviate the acute gastrointestinal toxicity in this population. The treatment protocol encompassed preoperative chemoradiotherapy using IMRT plus surgery for patients with clinical T3-4, N0-2 low rectal cancer. IMRT delivered 45 Gy per 25 fractions for gross tumors, mesorectal and lateral lymph nodal regions, and tried to reduce the volume of intestines receiving 15 Gy (V15 Gy) < 120 cc and V45 Gy ≤ 0 cc, respectively, while keeping target coverage. S-1 and irinotecan were concurrently administered. Acute gastrointestinal toxicity, rates of clinical downstaging, sphincter preservation, local regional control (LRC) and overall survival (OS) were evaluated. Twelve enrolled patients completed the chemoradiotherapy protocol. The volumes of intestines receiving medium to high doses were reduced by the current IMRT protocol compared to 3DCRT; however, the predefined constraint of V15 Gy was met only in three patients. The rate of ≥ grade 2 gastrointestinal toxicity excluding anorectal symptoms was 17%. The rates of clinical downstaging, sphincter preservation, three-year LRC and OS were 75%, 92%, 92% and 92%, respectively. In conclusion, preoperative chemoradiotherapy using IMRT for this population might alleviate acute gastrointestinal toxicity, achieving high LRC and sphincter preservation; although further advancement is required to reduce the irradiated volume of intestines, especially those receiving low doses.