Infiltration of Gastric Cancer Stroma by Tumor-Infiltrating Lymphocytes Correlates with Mechanistic Target of Rapamycin Signaling

INTRODUCTION

We investigated whether the infiltration of tumor-infiltrating lymphocytes (TILs) in gastric cancer (GC), as evaluated by hematoxylin and eosin (H&E) staining, could be a prognostic marker. We also explored on the relationship between TILs and mechanistic target of rapamycin (mTOR) and how it regulates immune effector responses in GC.

METHODS

A total of 183 patients with available data on TIL were included. TIL infiltration was evaluated using H&E staining. We also conducted immunohistochemistry to determine mTOR expression.

RESULTS

Positive TIL infiltration was defined as TILs ≥20%. There were 72 (39.3%) and 111 (60.7%) positive and negative cases, respectively. TILs positivity significantly correlated with both absence of lymph node metastasis (p = 0.037) and negative p-mTOR expression (p = 0.040). TIL infiltration correlated with a significantly better overall (p = 0.046) and disease-free (p = 0.020) survival.

CONCLUSION

mTOR possibly suppresses TIL infiltration in GC. H&E staining is an effective tool for evaluating the immune status of GC patients. H&E staining may be used in clinical practice to monitor treatment response in GC.

Sigmoid colon schwannoma difficult to distinguish from peritoneal dissemination 13 years after pancreatic neuroendocrine tumor surgery

BACKGROUND

Schwannoma, which clinicians sometimes struggle to diagnose, is a tumor arising from Schwann cells of peripheral nerves, often in the soft tissues and rarely in the gastrointestinal tract. Pancreatic neuroendocrine tumor (PNET) is rare among pancreatic tumors, and recurrence can occur long after resection. Here, we were presented with a case where a sigmoid colon schwannoma was difficult to distinguish from a postoperative recurrence of PNET and was diagnosed after laparoscopic resection.

CASE PRESENTATION

A 51-year-old man was diagnosed with PNET (NET G2) after a distal pancreatectomy (DP) 13 years ago. The patient underwent hepatectomy due to liver metastasis 12 years after initial radical surgery. The follow-up magnetic resonance imaging (MRI) after hepatectomy showed pelvic nodules, and laparoscopic surgery was performed for both diagnosis and treatment because peritoneal dissemination of PNET could not be ruled out. Since the tumor was in the sigmoid colon, a partial colon resection was performed. The histopathological diagnosis was a schwannoma, and the patient was discharged on the seventh postoperative day.

CONCLUSIONS

We experienced a case of sigmoid colon schwannoma that was difficult to differentiate from peritoneal dissemination of PNET and was later diagnosed after laparoscopic resection. In addition, this case involved a long-term postoperative recurrence of PNET that was amenable to radical resection, further establishing the importance of long-term imaging follow-up.

Robust Beam Selection Based on Water Equivalent Thickness Analysis in Passive Scattering Carbon-Ion Radiotherapy for Pancreatic Cancer

Carbon-ion radiotherapy (CIRT) is one of the most effective radiotherapeutic modalities. This study aimed to select robust-beam configurations (BC) by water equivalent thickness (WET) analysis in passive CIRT for pancreatic cancer. The study analyzed 110 computed tomography (CT) images and 600 dose distributions of eight patients with pancreatic cancer. The robustness in the beam range was evaluated using both planning and daily CT images, and two robust BCs for the rotating gantry and fixed port were selected. The planned, daily, and accumulated doses were calculated and compared after bone matching (BM) and tumor matching (TM). The dose-volume parameters for the target and organs at risk (OARs) were evaluated. Posterior oblique beams (120-240°) in the supine position and anteroposterior beams (0° and 180°) in the prone position were the most robust to WET changes. The mean CTV V95% reductions with TM were -3.8% and -5.2% with the BC for gantry and the BC for fixed ports, respectively. Despite ensuring robustness, the dose to the OARs increased slightly with WET-based BCs but remained below the dose constraint. The robustness of dose distribution can be improved by BCs that are robust to ΔWET. Robust BC with TM improves the accuracy of passive CIRT for pancreatic cancer.

Analysis of the relationship between LET, γH2AX foci volume and cell killing effect of carbon ions using high-resolution imaging technology

The strong cell killing effect of high linear energy transfer (LET) carbon ions is dependent on lethal DNA damage. Our recent studies suggest that induction of clusters of double-strand breaks (DSBs) in close proximity is one of the potential mechanisms. However, the relationship between LET, the degree of DSB clustering and the cell killing effect of carbon ions remains unclear. Here, we used high-resolution imaging technology to analyze the volume of γH2AX foci induced by monoenergetic carbon ions with a clinically-relevant range of LET (13-100 keV/μm). We obtained data from 3317 γH2AX foci and used a gaussian function to approximate the probability (p) that 1 Gy-carbon ions induce γH2AX foci of a given volume (vth) or greater per nucleus. Cell killing effects were assessed in clonogenic assays. The cell killing effect showed high concordance with p at vth = 0.7 μm3 across various LET values; the difference between the two was 4.7% ± 2.2%. This relationship was also true for clinical carbon ion beams harboring a mixed LET profile throughout a spread-out Bragg peak width (30-120 mm), with the difference at vth = 0.7 μm3 being 1.6% ± 1.2% when a Monte Carlo simulation-derived dose-averaged LET was used to calculate p. These data indicate that the cell killing effect of carbon ions is predictable by the ability of carbon ions to induce γH2AX foci containing clustered DSBs, which is linked to LET, providing the biological basis for LET modulation in the planning of carbon ion radiotherapy.

Primary tracheobronchial necrosis after esophagectomy: A nationwide multicenter retrospective study in Japan

Background

The clinical features of postoperative primary tracheobronchial necrosis (P‐TBN; the necrosis without anastomotic leakage or other cervical and mediastinal abscess) remains unclear. This nationwide multicenter retrospective study first investigated the clinical features of P‐TBN after esophagectomy for upper aerodigestive tract cancer with a large cohort.

Methods

As a study of the Japan Broncho‐Esophagological Society, a nationwide questionnaire survey was conducted in 67 institutions. The clinical data of 6370 patients who underwent esophagectomy for laryngeal, pharyngeal, and esophageal cancer between 2010 and 2019 were collected. Grades of P‐TBN were defined as follows: Grade 1, mucosal necrosis; Grade 2, transmural bronchial wall necrosis without fistula or perforation; Grade 3, transmural bronchial wall necrosis with fistula or perforation.

Results

P‐TBN was observed in 48 (0.75%) of 6370 patients. The incidences of P‐TBN for pharyngo‐laryngo‐cervical esophagectomy (PLCE; n = 1650), total pharyngo‐laryngo‐esophagectomy (TPLE; n = 205), and subtotal esophagectomy (SE; n = 4515) were 2.0%, 5.4%, and 0.1%, respectively. The upper mediastinal LN dissection (P = 0.016) and the higher level of the tracheal resection (P = 0.039) were significantly associated with a higher grade of necrosis in PLCE and TPLE. Overall survival rates were significantly lower in patients with Grade 2 (P = 0.009) and Grade 3 (P = 0.004) than in those with Grade 1.

Conclusion

The incidence of TBN restricted to P‐TBN was lower than previously reported. Maintaining the tracheal blood flow is essential to prevent worsening P‐TBN, especially in PLCE and TPLE. Our new P‐TBN severity grade may predict the outcome of patients with P‐TBN.

Albumin-derived Neutrophil-to-Lymphocyte Ratio Score as a Marker of Nivolumab Treatment Sensitivity in Gastric Cancer: A Multicenter Study

BACKGROUND/AIM

Establishment of powerful and easy-to-evaluate biomarkers that can predict immune checkpoint inhibitor sensitivity in patients with gastric cancer (GC) would be highly useful. The albumin-derived neutrophil-to-lymphocyte ratio (Alb-dNLR) score reportedly is an excellent measure of both immunity and nutritional status. However, the association between nivolumab treatment sensitivity and Alb-dNLR in GC has also not been adequately investigated. This multicenter retrospective study was designed to evaluate the association of Alb-dNLR with therapeutic sensitivity of nivolumab in GC patients.

PATIENTS AND METHODS

This was a retrospective multicenter study with patients from five sites. The data from 58 patients who received nivolumab for postoperative recurrent or unresectable advanced GC between October 2017 and December 2018 were analyzed. Blood tests had been performed before nivolumab administration. We analyzed the correlation between the Alb-dNLR score and clinicopathological factors, including best overall response.

RESULTS

Of the 58 patients, 21 (36.2%) comprised the disease control (DC) group and 37 (63.8%) comprised the progressive disease (PD) group. The nivolumab treatment responses were subjected to receiver operating characteristic analysis. The cutoff value was set to 2.90 g/dl for Alb and to 3.55 for dNLR. All eight patients in the high Alb-dNLR group had PD (p=0.0049). The low Alb-dNLR group had significantly better overall survival (p=0.0023) and progression-free survival rates (p<0.0001).

CONCLUSION

The Alb-dNLR score was a very simple and sensitive predictor of nivolumab therapeutic sensitivity and has very good biomarker properties.

Identification of a Functionally Efficient and Thermally Stable Outward Sodium-Pumping Rhodopsin (BeNaR) from a Thermophilic Bacterium

Rhodopsins are transmembrane proteins with retinal chromophores that are involved in photo-energy conversion and photo-signal transduction in diverse organisms. In this study, we newly identified and characterized a rhodopsin from a thermophilic bacterium, Bellilinea sp. Recombinant Escherichia coli cells expressing the rhodopsin showed light-induced alkalization of the medium only in the presence of sodium ions (Na⁺), and the alkalization signal was enhanced by addition of a protonophore, indicating an outward Na⁺ pump function across the cellular membrane. Thus, we named the protein Bellilinea Na⁺-pumping rhodopsin, BeNaR. Of note, its Na⁺-pumping activity is significantly greater than that of the known Na⁺-pumping rhodopsin, KR2. We further characterized its photochemical properties as follows: (i) Visible spectroscopy and HPLC revealed that BeNaR has an absorption maximum at 524 nm with predominantly (>96%) the all-trans retinal conformer. (ii) Time-dependent thermal denaturation experiments revealed that BeNaR showed high thermal stability. (iii) The time-resolved flash-photolysis in the nanosecond to millisecond time domains revealed the presence of four kinetically distinctive photointermediates, K, L, M and O. (iv) Mutational analysis revealed that Asp101, which acts as a counterion, and Asp230 around the retinal were essential for the Na⁺-pumping activity. From the results, we propose a model for the outward Na⁺-pumping mechanism of BeNaR. The efficient Na⁺-pumping activity of BeNaR and its high stability make it a useful model both for ion transporters and optogenetics tools.

Examining the Efficacy of Nivolumab for Gastric Cancer Focusing on Using an Inflammation-based Prognostic Score: A Multicenter Retrospective Study

BACKGROUND/AIM

To discover the positive therapeutic effects of nivolumab in patients with advanced gastric cancer (AGC), it is necessary to establish a useful biomarker to predict therapeutic efficacy. This multicenter retrospective study sought to evaluate the predictive impact of inflammation-based prognostic score (IBPS) on the therapeutic efficacy of nivolumab in patients with AGC.

PATIENTS AND METHODS

In this retrospective study, we evaluated 58 AGC patients treated with nivolumab from October 2017 to November 2018 at five institutes. Patients were categorized follows: progressive disease (PD) or disease control (DC). Blood chemistry tests were performed immediately before and after two courses of nivolumab; the correlation between best overall response and IBPS was investigated. Transition of each blood serum marker was also assessed.

RESULTS

Of 58 patients, 37 (63.8%) were in the PD group and 21 (36.2%) in the DC group. No positive correlation was noted between IBPS and therapeutic efficacy of nivolumab both immediately before and after two courses of nivolumab. However, the neutrophil-lymphocyte ratio (NLR) (p=0.045) and prognostic index (PI) (p=0.0042) before nivolumab and NLR (p=0.025), PI (p=0.0030) and Glasgow prognostic score (GPS) (p=0.043) after nivolumab were significantly correlated with treatment sensitivity. Furthermore, a decrease in PNI was an independent prognostic factor to predict nivolumab resistance on univariate analyses (p=0.0051).

CONCLUSION

Although no association between IBPS and therapeutic sensitivity was found, it is important to focus on the transition of PNI to predict therapeutic efficacy of nivolumab.

Evaluation of a therapeutic carbon beam using a G2000 glass scintillator

A G2000 glass scintillator (G2000-SC) was used to determine the carbon profile and range of a 290-MeV/n carbon beam used in heavy-ion therapy because it was sensitive enough to detect single-ion hits at hundreds of mega electron Volts. An electron-multiplying charge-coupled device camera was used to detect the ion luminescence generated during the irradiation of G2000-SC with the beam. The resulting image showed that the position of the Bragg peak can be determined. The beam passes through the 112-mm-thick water phantom and stops 5.73 ± 0.03 mm from the incident side to the G2000-SC. Additionally, the location of the Bragg peak was simulated when irradiating G2000-SC with the beam using the Monte Carlo code particle and heavy ion transport system (PHITS). Simulation results show that the incident beam stops at 5.60 mm after entering G2000-SC. The beam stop location obtained from images and the PHITS code is defined at 80% distal fall-off from the Bragg peak position. Consequently, G2000-SC provided effective profile measurements of therapeutic carbon beams.

Gangrenous ischemic colitis localized to the cecum: a case report

BACKGROUND

Ischemic colitis affects the left colon in elderly individuals and localization on the right side, especially in the cecum, is rare. We report a case of gangrenous ischemic colitis localized in the cecum of a patient undergoing hemodialysis.

CASE PRESENTATION

A 73-year-old man had been undergoing hemodialysis for chronic renal failure caused by diabetic nephropathy. He experienced frequent vomiting, diarrhea, and abdominal pain. Contrast-enhanced computed tomography revealed thickening of the cecal wall, poor enhancement, dilation of the cecum, and intrahepatic portal emphysema. No obvious abnormal findings were observed in the appendix. The patient was diagnosed with cecal necrosis and ileocecal resection was performed. Histopathological examination revealed gangrenous ischemic colitis of the cecum. He was discharged 12 days after surgery without postoperative complications.

CONCLUSION

It is important to consider the possibility of ischemic colitis of the right colon in the event of renal failure requiring dialysis, to ensure that opportunities for surgical intervention are not missed.

Selective IR super-resolution imaging of β-keratins at the bulk or interface in feather detected by using a nonlinear optical process

We developed the new IR super-resolution microscope by using a 4-wave mixing (4-wave), which is a third-order nonlinear optical process, and carried out the IR super-resolution imaging of the cross section of the rachis of an avian feather. We clearly observed strong signals in the entire region of the rachis at the amide I vibration of β-keratin in both of the XXYY and YYXX polarization combination. These results are different from images detected by using the vibrational sum-frequency generation (VSFG) method. While the VSFG imaging detects molecules only from the interface, the 4-wave method enables us to observe the signal from the bulk area. We concluded that the four repeating units of β-keratins in the bulk area which are suggested by X-ray diffraction studies are visualized in the 4-wave detected method. We also applied two IR super-resolution microscopies for the barb and discuss the site dependence of the orientation, distribution and concentration of β-keratin.

Preoperative Risk Factors and Prognostic Impact of Postoperative Complications Associated with Total Gastrectomy

INTRODUCTION

We evaluated the risk factors for patients with gastric cancer (GC) undergoing total gastrectomy (TG) that predict postoperative complications, including anastomotic leakage, postoperative pneumonia, and heart disease.

METHODS

We collected 106 patients who received TG for GC between May 2009 and May 2017 at Gunma University Graduate School of Medicine, including clinicopathologic, surgical, postoperative complication, laboratory test, and physiologic test data.

RESULTS

Of 106 patients, 92 (86.8%) had no complications, and 14 (13.2%) had complications. Univariate analyses revealed that a high American Society of Anaesthesiologists physical status (ASA-PS) and neutrophil-lymphocyte ratio (NLR) of ≥3.5 significantly correlated with postoperative complications. Multivariate analyses showed that high ASA-PS was an independent prognostic factor of postoperative complications. The cancer recurrence rate was 34.8% in the noncomplication group and 71.4% in the complication group.

CONCLUSION

Patients with postoperative complications are prone to recurrence and poor prognosis. For patients with high-risk GC with poor ASA-PS and high NLR, more thorough perioperative management is essential.

Significance of routine preoperative prone computed tomography for predicting intractable cases of inguinal hernias treated by transabdominal preperitoneal repair

Physical examination is the standard diagnostic approach for adult inguinal hernias. We aimed to evaluate the clinical utility of routine preoperative computed tomography scans in the prone position for predicting intractable cases of inguinal hernias before performing transabdominal preperitoneal repairs. We retrospectively analyzed 56 lesions in 48 patients with inguinal hernias who underwent prone computed tomography scans prior to transabdominal preperitoneal repairs. To assess the ability of prone computed tomography to enable the accurate preoperative diagnosis of inguinal hernias, we compared preoperative hernia types as classified through hernia computed tomography and intraoperative diagnosis. We also analyzed the relationship between operation time and hernia type in unilateral cases (n = 40). The overall hernia computed tomography detection and classification accuracy rates were 81.0% and 83.9%, respectively, using the Japan Hernia Society classification system (2009 version) and 84.3% and 91.2%, respectively, using the European Hernia Society classification system. There were no differences in the hernia type frequencies between the shorter (n = 20) and longer (n = 20) operation time groups. Two patients had sliding inguinal hernias with prolapsing bladders, both of which were detectable using preoperative prone computed tomography. Although transabdominal preperitoneal repairs were completed in both cases, the operation times were exceptionally long (185 and 291 minute). Preoperative prone computed tomography is useful for predicting intractable cases of inguinal hernias. Prone computed tomography can play a significant role in not only typing and differentiating hernias from other diseases, but also in helping surgeons appropriately treat unexpected intractable cases with laparoscopic surgery.

Congenital portopulmonary shunt in a cat

A 9-year-old spayed female crossbreed cat with chief complaints of anorexia and hypersalivation had high serum concentrations of ammonia and fasting and postprandial total bile acid. Therefore, she was referred to our hospital. On the first evaluation, haematology, serum chemistry, radiography and ultrasonography findings suggested that she had a congenital portosystemic shunt. CT revealed a shunt vessel from the left gastric vein to the left pulmonary vein. During median celiotomy and sternotomy, gross findings and mesenteric portography revealed abnormal vessel shunting from the left gastric vein to the left pulmonary vein. Complete ligation of the shunt vessel was achieved. She recovered without any complications. Postoperative serum chemistry revealed that ammonia and total bile acid levels decreased to within the reference intervals. This report is the first to describe the clinical features and surgical outcome of a cat with a congenital portopulmonary shunt.

Primary tracheobronchial necrosis after esophagectomy: A nationwide multicenter retrospective study in Japan

Background

The clinical features of postoperative primary tracheobronchial necrosis (P-TBN; the necrosis without anastomotic leakage or other cervical and mediastinal abscess) remains unclear. This nationwide multicenter retrospective study first investigated the clinical features of P-TBN after esophagectomy for upper aerodigestive tract cancer with a large cohort.

Methods

As a study of the Japan Broncho-Esophagological Society, a nationwide questionnaire survey was conducted in 67 institutions. The clinical data of 6370 patients who underwent esophagectomy for laryngeal, pharyngeal, and esophageal cancer between 2010 and 2019 were collected. Grades of P-TBN were defined as follows: Grade 1, mucosal necrosis; Grade 2, transmural bronchial wall necrosis without fistula or perforation; Grade 3, transmural bronchial wall necrosis with fistula or perforation.

Results

P-TBN was observed in 48 (0.75%) of 6370 patients. The incidences of P-TBN for pharyngo-laryngo-cervical esophagectomy (PLCE; n = 1650), total pharyngo-laryngo-esophagectomy (TPLE; n = 205), and subtotal esophagectomy (SE; n = 4515) were 2.0%, 5.4%, and 0.1%, respectively. The upper mediastinal LN dissection (P = 0.016) and the higher level of the tracheal resection (P = 0.039) were significantly associated with a higher grade of necrosis in PLCE and TPLE. Overall survival rates were significantly lower in patients with Grade 2 (P = 0.009) and Grade 3 (P = 0.004) than in those with Grade 1.

Conclusion

The incidence of TBN restricted to P-TBN was lower than previously reported. Maintaining the tracheal blood flow is essential to prevent worsening P-TBN, especially in PLCE and TPLE. Our new P-TBN severity grade may predict the outcome of patients with P-TBN.

Development and Applications of Compton Camera-A Review

The history of Compton cameras began with the detection of radiation sources originally for applications in astronomy. A Compton camera is a promising γ-ray detector that operates in the wide energy range of a few tens of keV to MeV. The γ-ray detection method of a Compton camera is based on Compton scattering kinematics, which is used to determine the direction and energy of the γ-rays without using a mechanical collimator. Although the Compton camera was originally designed for astrophysical applications, it was later applied in medical imaging as well. Moreover, its application in environmental radiation measurements is also under study. Although a few review papers regarding Compton cameras have been published, they either focus very specifically on the detectors used in such cameras or the particular applications of Compton cameras. Thus, the aim of this paper is to review the features and types of Compton cameras and introduce their applications, associated imaging algorithms, improvement scopes, and their future aspects.

Visualizing Bioabsorbable Spacer Effectiveness by Confirming the Distal-Tail of Carbon-Ion Beams: First-In-Human Report

In particle therapy, bioabsorbable polyglycolic acid (PGA) spacer was developed to reduce the healthy organ irradiation dose, especially in the gastrointestinal tract. The PGA spacer is safe and effective; however, there are no reports that have confirmed whether the PGA spacer which inserted in the body actually stops the carbon-ion (C-ion) beams. Here, we visualized and confirmed that the PGA spacer stops the C-ion beams in the body based on the dose distribution using auto-activation positron emission tomography (AAPET). A 59-year-old dedifferentiated retroperitoneal liposarcoma patient underwent C-ion radiotherapy (C-ion RT) on referral. A month before C-ion RT initiation, the patient underwent PGA spacer placement. Postoperatively, the patient received 4.4 Gy (RBE) per fraction of C-ion RT, followed by AAPET. AAPET revealed lower positron emitter concentrations at the distal tissue ventral to the PGA spacer than in the planning target volume. In observing the efficacy of the PGA spacer, the AAPET images and the average count per second of the positron emitter suggested that the PGA spacer stopped the C-ion beams in the body in accordance with the dose distribution. Therefore, AAPET was useful in confirming the PGA spacer's effectiveness in this study, and the PGA spacer stopped the C-ion beams.

PROX1 was associated with LGR5 and Wnt signaling and contributed to poor prognosis in gastric cancer

Introduction: We investigated prospero homeobox protein-1 (PROX1) expression in gastric cancer (GC) as a prognostic marker and its relationship with LGR5 and Wnt/β-catenin activity in GC. Methods: A total of 196 cases of patients who underwent GC surgery were retrospectively collected and reviewed. PROX1, LGR5, Wnt3a, and β-catenin expression was evaluated by using immunohistochemistry. The relationship between PROX1 expression and clinicopathological features was also evaluated. Results: The PROX1 low-expression group had 105 patients (53.6%) and the high-expression group 91 patients (46.4%). For LGR5, 76 patients (38.8%) had low expression and 120 (61.2%) high expression. The PROX1 low-expression group was significantly younger (p = 0.0095), had more intestinal type (p = 0.014), and smaller tumor size (p = 0.013). The PROX1 high-expression group significantly correlated with high LGR5 expression (p < .0001) and high Wnt3a expression (p = 0.012). There were more cases of postoperative recurrence in the PROX1 high-expression group (p = 0.013). Conclusion: Our findings show that PROX1 correlates with LGR5 and Wnt3a signaling in GC and has a poor prognosis with postoperative recurrence.

Changes in the Gustave Roussy Immune Score as a Powerful Prognostic Marker of the Therapeutic Sensitivity of Nivolumab in Advanced Gastric Cancer: A Multicenter, Retrospective Study

BACKGROUND

Identification of positive biomarkers for the effects of nivolumab on patients with advanced gastric cancer (AGC) is significant. The Gustave Roussy Immune Score (GRIm-s) is associated with therapeutic resistance of immune checkpoint inhibitors (ICIs) in other cancers. This multicenter, retrospective study was designed to analyze the association of GRIm-s with therapeutic sensitivity of nivolumab in patients with AGC.

METHODS

We reviewed 58 patients with AGC treated with nivolumab from October 2017 to November 2018 at five participating institutions. We performed blood tests before the start of nivolumab and after administration of two courses. We evaluated the correlation between the best overall response and GRIm-s. Additionally, we focused on the changes in GRIm-s before the start of nivolumab and after administration of two courses.

RESULTS

Of the 58 patients, 21 (36.2%) were classified into the disease control (DC) group and 37 (63.8%) into the progressive disease (PD) group. GRIm-s before nivolumab treatment did not correlate with the best therapeutic response (p = 0.086). However, GRIm-s after two courses of nivolumab showed that significantly more PD cases were in the high-risk group (p < 0.0001). After two courses of nivolumab, overall survival was significantly worse in the high-risk group (p < 0.0001). For progression-free survival, the high-risk group had a significantly worse prognosis both before (p = 0.04) and after two courses of nivolumab treatment (p < 0.0001).

CONCLUSIONS

GRIm-s after two courses of nivolumab and its changes compared to pretreatment values proved beneficial in predicting nivolumab sensitivity.

Patient-Derived Training Simulator for Image-Guided Adaptive Brachytherapy of Locally Advanced Cervical Cancers: Development and Initial Use

Image-guided adaptive brachytherapy (IGABT) using intracavitary and interstitial (IC/IS) techniques plays a pivotal role in definitive radiotherapy for locally advanced cervical cancers. However, the training opportunities for interstitial needle application are limited, preventing this technique from becoming widespread. This study aimed to develop a training simulator for IC/IS brachytherapy. The simulator consists of a soft silicone tumor phantom and acrylic tube mimicking the vagina; it has high visibility because of translucent materials and is compatible with computed tomography (CT) and magnetic resonance imaging (MRI). A patient harboring a typical bulky and irregular-shaped cervical tumor was selected from 495 in-house IGABT-treated candidates, and a tumor phantom (68 × 49 × 45 mm) modeled on this patient was produced from three-dimensional real-scale measurements of the MRI-based high-risk clinical target volume at first brachytherapy. In trial use by two physicians with different levels of IGABT skills, a Fletcher-Suit Asian Pacific applicator, and a Venezia applicator with interstitial needles were nicely applied to the simulator, facilitating successful creation of CT-based treatment plans consistent with clinical practice. Thus, the training simulator can be useful for the training of IC/IS brachytherapy, and warrants further research employing a greater number of phantoms and practitioners to verify its educational value.

Idiopathic pneumoperitoneum diagnosed following high-energy motor vehicular trauma:a case report

Intra-abdominal free gas is a finding of extra-intestinal gas in the abdominal cavity on radiography or CT, mainly suggesting gastrointestinal perforation and necessitating emergency surgery. Idiopathic pneumoperitoneum is diagnosed when there is no obvious gastrointestinal perforation, but there is presence of free gas in the abdominal cavity with an unidentifiable cause. Herein, we report a case of idiopathic pneumoperitoneum secondary to high-energy trauma following a car rollover accident. A 95-year-old man was transferred to our clinic after a car-to-car rollover accident. He had abrasions on his right upper arm and left abdomen that appeared to be the result of the accident;however, no other apparent traumatic injuries were noted. There was no pain in the abdomen, and peritoneal irritation symptoms were also not noted. A CT scan showed fine free air. Although idiopathic pneumoperitoneum could not be ruled out, considering the patient's background and the possibility of traumatic small bowel perforation, emergency surgery was performed. A thorough search of the abdominal cavity was performed;however, the surgery was completed without an obvious perforation site. Idiopathic pneumoperitoneum should be considered as a differential disease in cases who have free air on abdominal CT but clinically lack obvious inflammatory reaction findings. J. Med. Invest. 69 : 155-157, February, 2022.

ASO Author Reflections: Impact of the Ratio of the Visceral Fat Area (VFA) to Psoas Muscle Area (PMA) (V/P Ratio) on Survival for Patients with Surgically Resected Esophageal Cancer

PAST: The true impact of co-occurring muscle mass reduction and fat accumulation on patients with surgically resected esophageal cancer (EC) remains controversial. PRESENT: The current study defined reduction in muscle mass and excess body adiposity as the ratio of the visceral fat area (VFA) to the psoas muscle area (V/P ratio) on the same axial computed tomography slice at the third lumbar vertebra (L3). A high V/P ratio was associated with greater age (p = 0.03), higher body mass index (BMI) (p < 0.001), larger VFA (p < 0.001), and increased age-adjusted Charlson comorbidity index (ACCI) (p = 0.005). Multivariate analysis showed a high V/P ratio to be an independent prognostic factor for poor overall survival (OS) of EC patients who underwent surgery (p = 0.003). The prognostic value of the V/P ratio still was significant for EC patients with a BMI lower than 25 kg/m2. FUTURE: A high V/P ratio was an independent prognostic factor for OS of EC patients who underwent surgery, even BMI-defined non-obese EC patients. The V/P ratio as a surrogate marker of relative muscle mass reduction and fat accumulation may have prognostic value for EC patients regardless of body composition differences.

Normal Tissue Complication Probability Model for Acute Radiation Dermatitis in Patients with Head and Neck Cancer Treated with Carbon Ion Radiotherapy

PURPOSE

This study aimed to explore the prognostic factors associated with acute radiation dermatitis (ARD). A normal tissue complication probability (NTCP) model for ARD in patients with head and neck cancer (HNC) treated with carbon ion radiotherapy (CIRT) was developed.

MATERIALS AND METHODS

A total of 187 patients were included in the analysis, and the endpoint was ≥grade 2 ARD. The biological and physical dose-surface parameters associated with ARD were used in the logistic regression model. The mean areas under the receiver operating characteristic curve (AUC) in the internal cross-validation and Akaike's corrected Information Criterion (AICc) were examined for model evaluation and selection. The multivariate logistic regression NTCP models were established based on factors with weak correlation.

RESULTS

Tumour volume, planning target volume to the skin, radiation technique and all dose-surface parameters were significantly associated with ARD (P < 0.05). Models with high performance for grade 2-3 ARD were constructed. The most significant prognostic predictors were S_{40 Gy (relative biological effectiveness, RBE)} and S_{20 Gy} [absolute surface area receiving RBE-weighted dose of 40 Gy (RBE) or physical dose of 20 Gy]. The internal cross-validation-based AUCs for models with S_{40 Gy (RBE)} and S_{20 Gy} were 0.78 and 0.77, respectively. The biological and physical dose-surface parameters had similar performance at various dose levels. However, the performance of the multivariate NTCP models based on two factors was not better than that of the univariate models.

CONCLUSIONS

NTCP models for ARD may provide a basis for the development of individualised treatment strategies and reduce the incidence of severe ARD in patients with HNC receiving CIRT. Furthermore, biological and physical dose-surface parameter-based models are comparable. However, further validation with more evaluation parameters is warranted.