Transarterial embolization of radicular arteriovenous fistula at the craniocervical junction

Craniocervical junction arteriovenous fistula (CCJ AVF) is a rare vascular disorder. Direct surgery for CCJ AVF is generally reported to have better outcome compared to endovascular treatment. However, no certain consensus has been obtained so far. We report a case of radicular CCJ AVF treated by transarterial embolization that resulted in a good outcome. A 69-year-old man presented with subarachnoid hemorrhage primarily in the posterior cranial fossa. Based on digital subtraction angiography showed radicular CCJ AVF with varix. Transarterial embolization was performed with n-butyl-2-cyanoacrylate on day 17 after onset and successfully cured. The neurovascular anatomy of CCJ AVF is complicated, but endovascular treatment may be a treatment option with detailed understanding of angioarchitecture and selective endovascular procedure.

Macroscopic type is implicated in the prognostic impact of initial chemotherapy on peritoneal lavage cytology-positive gastric cancer with no other noncurative factors

BACKGROUND

Initial chemotherapy (Initial-C) followed by surgery is a promising treatment strategy for peritoneal lavage cytology-positive gastric cancer (CY1 GC) with no other noncurative factors. The aim of this study was to investigate the survival advantage of Initial-C compared to initial surgery (Initial-S) for this disease according to the macroscopic type, which was associated with prognosis and the efficacy of chemotherapy in GC.

METHODS

One hundred eighty-nine patients who were diagnosed with CY1 GC with no other noncurative factors at four institutions from January 2007 to December 2018 were enrolled. The patients were divided into a macroscopic type 4 group (N = 48) and a non-type 4 group (N = 141). The influence of initial treatment on overall survival (OS) in each group was evaluated.

RESULTS

In the type 4 group, the 5-year OS rates of Initial-C (N = 35) and Initial-S (N = 13) were 11.6% and 0%, respectively (P = 0.801). The multivariate analysis could not show the survival advantage of Initial-C. In the non-type 4 group, the 5-year OS rates of Initial-C (N = 41) and Initial-S (N = 100) were 48.4% and 29.0%, respectively (P = 0.020). The multivariate analysis revealed that Initial-C was independently associated with prolonged OS (hazard ratio, 0.591; 95% confidence interval, 0.375-0.933: P = 0.023).

CONCLUSIONS

Initial-C improves the prognosis of non-type 4 CY1 GC with no other noncurative factors. On the other hand, further development of effective chemotherapeutic regimens and innovative treatment strategies are required for type 4 CY1 GC.

Mucin phenotype and genetic alterations in non-V600E BRAF-mutated colorectal cancer

Colorectal cancer (CRC) is a heterogeneous disease that develops through stepwise accumulation of genetic alterations and progresses via several distinct pathways. However, the tumorigenesis of CRCs with BRAF non-V600E mutations remains unclear. Here, we aimed to elucidate the tumorigenesis of CRCs with BRAF non-V600E mutations, focusing on differences in mucin phenotype and genetic alterations between CRCs with non-V600E and V600E mutations. We investigated 201 patients with CRC and performed panel testing of 415 genes to identify BRAF mutations. Patients were classified into five mucin phenotypes - large-intestinal, small-intestinal, gastric, mixed, and unclassified - using immunohistochemistry for CD10, MUC2, MUC5AC, and MUC6. BRAF mutations were identified in 24 of 201 patients' samples, of which 13 (6.5%) had a V600E mutation (V600E-mutant) and 11 (5.5%) had non-V600E mutations (non-V600E-mutant). MUC5AC expression was significantly associated with V600E mutations (P = 0.040), while CD10 expression was significantly associated with non-V600E mutations (P = 0.010). The small-intestinal mucin phenotype was significantly associated with non-V600E mutations (P = 0.031), while the mixed mucin phenotype was significantly associated with V600E mutations (P = 0.027). Regarding genetic alterations, focusing on the WNT signaling pathway, APC mutation was significantly associated with non-V600E mutations (P < 0.001), while RNF43 mutation was significantly associated with V600E mutations (P = 0.020). Considering the differences in mucin phenotype and genetic alterations, different modes of tumorigenesis are assumed for CRC with BRAF V600E mutation and non-V600E mutations. These findings are important in understanding the biology and treatment strategies for BRAF-mutant CRC.

Risk factors for death from other diseases after curative gastrectomy and lymph node dissection for gastric cancer

BACKGROUND

Recent advances in treatment are expected to bring a cure to more patients with gastric cancer (GC). Focusing on the risk of death from other diseases (DOD) has become a crucial issue in patients cured of GC. The aim of this study was to elucidate the risk factors for DOD in patients who underwent curative gastrectomy with lymph node dissection for GC.

METHODS

We enrolled 810 patients who underwent curative gastrectomy with lymph node dissection for GC from January 1990 to December 2014 and had no recurrence or death of GC until December 2019. We investigated the risk factors for DOD defined as death excluding death from a malignant neoplasm, accident, or suicide after gastrectomy, focusing on the perioperative characteristics at gastrectomy.

RESULTS

Among 315 deaths from any cause, 210 died from diseases other than malignancy, accidents and suicide. The leading cause of DOD was pneumonia in 54 patients (25.7%). The actual survival period in 167 patients (79.5%) with DOD was shorter than their estimated life expectancy at gastrectomy. Multivariate analysis revealed that a high Charlson Comorbidity Index score (score 1-2: hazard ratio [HR] 2.192, 95% confidence interval [CI] 1.713-2.804, P < 0.001 and score ≥ 3: HR 4.813, 95% CI 3.022-7.668, P < 0.001), total gastrectomy (HR 1.620, 95% CI 1.195-2.197, P = 0.002) and the presence of postoperative complications (HR 1.402, 95% CI 1.024-1.919, P = 0.035) were significant independent risk factors for DOD after gastrectomy for GC, in addition to age of 70 years or higher, performance status of one or higher and body mass index less than 22.0 at gastrectomy.

CONCLUSIONS

Pneumonia is a leading cause of DOD after curative gastrectomy and lymph node dissection for GC. Paying attention to comorbidities, minimizing the choice of total gastrectomy and avoiding postoperative complications are essential to maintain the long-term prognosis after gastrectomy.

[Long-Term Survival after Liver and Pulmonary Metastasectomy Following Chemotherapy for Metastatic Pancreatic Ductal Adenocarcinoma-A Case Report]

The patient was a 61-year-old man with a diagnosis of carcinoma of the pancreatic head. Abdominal computed tomography( CT)showed no distant metastasis, and he underwent subtotal stomach-preserving pancreatoduodenectomy. Immediately after surgery, he received liver perfusion chemotherapy with 5-fluorouracil followed by systemic gemcitabine. Eighteen months after surgery, CT revealed liver metastasis in the S6 segment, and partial hepatectomy was performed. The pathological diagnosis was liver metastasis of pancreatic cancer. Postoperatively, the patient was treated with gemcitabine and S-1 therapy for 1 year and then switched to S-1 monotherapy for about 6 months. Four years after the initial surgery, CT showed 2 metastases in the right lung. After 2 months of S-1 monotherapy, wedge resection of the upper and lower lobes of the right lung was performed. Gemcitabine and nab-paclitaxel therapy were administered, after the metastasectomy, but pleural dissemination appeared on CT 5 years after the initial surgery. Modified FOLFIRINOX therapy was started and continued for 8 months, but CT revealed further disseminated lesions in the diaphragm. Palliative irradiation was provided, but the disease gradually progressed. After multidisciplinary treatment, the patient survived for 6 years and 3 months after the initial surgery.

[A Case of Esophageal Carcinoma with Tracheal Invasion after Preoperative Treatment with Docetaxel, Cisplatin, and 5-Fluorouracil in Which Definitive Chemoradiotherapy and Salvage Esophagectomy Prolonged Survival]

A 57-year-old man was diagnosed as having resectable advanced esophageal carcinoma adjacent to the trachea(Ut, cT3N0M0)and received preoperative docetaxel, cisplatin, and 5-fluorouracil therapy. Due to tracheal tumor invasion and upstaging to cT4bN0M0 after 1 course of chemotherapy, the treatment was converted to definitive chemoradiotherapy (CRT). A remarkable response with no evidence of tracheal invasion was observed on computed tomography following definitive CRT. He underwent successful curative resection with salvage esophagectomy, and the resected tumor was staged as pT1bN0M0. No adjuvant therapy was administered, and the patient was alive with no evidence of disease at the 5-year postoperative follow-up. The response to preoperative treatment should be meticulously assessed and appropriate treatment modalities used to avoid overlooking the potential for cure, even if the response to preoperative treatment with docetaxel, cisplatin, and 5-fluorouracil is poor.

[Cancer of the Ascending Colon and Left Breast in an Older Adult Complicated by Thoracic Aortic Aneurysm]

An 87-year-old woman with a gradually enlarging mass in her left breast, diagnosed as having left-sided breast cancer with skin invasion by a local practitioner, was referred to our hospital. Computed tomography revealed ascending colon cancer with abdominal wall invasion and a thoracic aortic aneurysm(Stanford type B), in addition to breast cancer with skin invasion. A thoracic endovascular aortic repair and bypass surgery between the subclavian arteries were both performed for the thoracic aortic aneurysm. After 6 days, a right hemicolectomy and D2 lymphadenectomy were performed for the ascending colon cancer. A postoperative pathological diagnosis of pT3N0M0, pStage Ⅱa, was made. A total left mastectomy with a full-thickness skin graft for left breast cancer was performed after 2 months following the ascending colon cancer surgery. The postoperative pathological diagnosis was pT3N0M0, pStage ⅡB. No evidence of local recurrence or distant metastasis of the ascending colon cancer has been observed at 20 months postoperatively, or of the breast cancer after 18 months following surgery.

[A Case of Appendiceal Carcinoma with BRAF V600E Mutation and Microsatellite Instability-High]

A 75-year-old woman presented to our hospital with abdominal pain and melena. Colonoscopy revealed an ulcer at the appendiceal orifice. Histopathological examination of biopsy specimens revealed adenocarcinoma. Computed tomography showed an appendiceal mass of 11.8×6.7 cm in size involving the cecum and terminal ileum without any distant metastatic findings. Ileocecal resection with regional lymph node dissection to the root of the ileocolonic artery was performed. Histopathological examination of the specimen revealed appendiceal adenocarcinoma. Molecular subtype of the tumor was BRAF V600E mutation and microsatellite instability-high(MSI-H). The pathological stage was pT4bpN1bcM0, pStage ⅢC. She received 8 courses of CapeOX as adjuvant chemotherapy and no recurrence was noted 12 months following the surgery. The establishment of standard treatment strategies including surgery, chemotherapy, and immunotherapy for carcinoma of the appendix with BRAF V600E mutation and/or MSI-H is needed.

[Surgery for Cholangiocarcinoma with Superficial Spread and Lymph Node Metastasis-Report of a Long-Term Survivor Who Had Positive Proximal Ductal Resection Margins with Carcinoma In Situ]

A 66-year-old man was referred to our hospital with fever and abdominal pain. CT showed a mass in the intrapancreatic bile duct but no wall thickness in the perihilar bile ducts. Neither regional lymphadenopathy nor distant metastasis was observed. Biliary cytology showed adenocarcinoma. The diagnosis was distal cholangiocarcinoma, and pancreatoduodenectomy was performed. Intraoperative frozen section examination of the ductal resection margins at the right and left hepatic ducts was positive for carcinoma in situ, and the operation ultimately completed with R1 resection. Histological examination confirmed a diagnosis of cholangiocarcinoma with superficial spread and a single positive lymph node. Adjuvant chemotherapy with S-1 was administered for 1 year. Anastomotic recurrence at the hepaticojejunostomy was found 5 years after resection; biopsy specimens revealed adenocarcinoma. Thereafter, S-1 chemotherapy was resumed, and the patient remains alive and well 9 years and 1 month after resection.

[A Case of Intraductal Papillary Mucinous Adenocarcinoma with Hepatic Dysfunction Due to Tumor Perforation into the Bile Duct]

A 58-year-old woman presented with a complaint of weight loss. Abdominal computed tomography showed dilatation of the biliary and pancreatic ducts and a mural nodule in the pancreatic duct. The diagnosis was intraductal papillary mucinous neoplasm(IPMN). Endoscopic retrograde cholangiopancreatography(ERCP)and cholangioscopy revealed a fistula between the common bile duct and the IPMN. A sudden increase in hepatobiliary enzymes was noted preoperatively. ERCP showed that the common bile duct was obstructed by mucus. A nasobiliary drainage tube was inserted into the bile duct endoscopically and kept open by daily tube washing, and the liver dysfunction improved. Total pancreatectomy, splenectomy, and regional lymph node dissection were performed. Histological examination confirmed that the primary tumor was mixed invasive intraductal papillary mucinous adenocarcinoma. The patient remains alive and well with no evidence of recurrence 18 months after resection.

[Two Operations for Intrahepatic Recurrence of Biliary Cystadenocarcinoma-A Long-Term Survivor]

We report a case of biliary cystadenocarcinoma in which long-term survival was achieved after 2 operations for intrahepatic recurrence. A 72-year-old man with biliary cystadenocarcinoma located mainly in segment 3 of the liver underwent left hepatectomy, extrahepatic bile duct resection, and lymph node dissection. Seven years and 9 months after the initial resection, he underwent partial liver resection(segment 5)for intrahepatic recurrence detected by computed tomography. Fifteen years and 7 months after the initial resection, he underwent repeat partial resection of the liver(segment 5)for intrahepatic recurrence. Histologically, these tumors were confirmed to be recurrence of biliary cystadenocarcinoma. He remains alive and well with no further recurrence 21 years and 6 months after the initial resection. This case and a literature review suggest that hepatic resection is a useful treatment option for intrahepatic recurrence of biliary cystadenocarcinoma.

[Resectable Pancreatic Cancer Successfully Treated with Neoadjuvant Chemotherapy Regimen Change to Modified FOLFIRINOX-A Case Report]

A 72-year-old woman presented with obstructive jaundice. Computed tomography revealed a 12-mm low-density mass in the head of the pancreas. She was diagnosed as having pancreatic cancer by endoscopic ultrasound-guided fine-needle aspiration. She received gemcitabine plus nab-paclitaxel as preoperative chemotherapy. After 2 courses, hepatoduodenal lymph node metastasis appeared and was accompanied by increased tumor marker levels. The regimen was changed to modified FOLFIRINOX. After 5 courses, the lymph node metastasis was reduced in size and the tumor marker levels were decreased, so subtotal stomach-preserving pancreaticoduodenectomy was performed. Adjuvant chemotherapy was administered postoperatively. The patient was alive and well without recurrence 2 years and 9 months after the surgery, but died of sepsis. Nevertheless, this case highlights that when preoperative chemotherapy for resectable pancreatic cancer appears to be ineffective, a change in regimen may be useful.

Axillary cutaneous metastasis of colon cancer with microsatellite instability-high and BRAF V600E mutation treated with curative-intent surgery: a case report

BACKGROUND

Colorectal cancer (CRC) metastasizes to various organs, while cutaneous metastases are rare. Although there have been several previous reports of axillary cutaneous metastases with other metastases of CRC, there has never been a report of axillary cutaneous metastasis of CRC that could be treated with curative-intent surgery.

CASE PRESENTATION

A 68-year-old female was diagnosed with an axillary cutaneous tumor and ascending colon cancer with invasion to the duodenum. Histopathological and immunohistochemical analysis revealed that the axillary cutaneous tumor showed adenocarcinoma and the same expression pattern for cytokeratin 7, cytokeratin 20, and CDX2 as the ascending colon cancer, and that proved to be KRAS-NRAS wild type, MSI-H, and with a BRAF V600E mutation. The patient underwent a two-stage resection with curative intent after receiving neoadjuvant chemotherapy which consisted of one cycle of modified FOLFOX6 followed by two cycles of FOLFOXIRI. During and after the two operations, the patient received a total of nine cycles of modified FOLFOX6 as adjuvant chemotherapy. Two years after the initial surgery, and 1 year and 8 months after the second surgery, the patient is alive without recurrence.

CONCLUSIONS

To the best of our knowledge, this is the first report of axillary cutaneous metastasis of CRC with microsatellite instability-high and BRAF V600E mutation that could be treated with curative-intent surgery. It is important to recognize the presence of such cases for the accurate diagnosis and treatment of CRC with cutaneous metastasis.

In-stent stenosis after stenting the PulseRider for a middle cerebral artery aneurysm: A case report

PulseRider is a self-expanding stent implant used to treat wide-necked aneurysms. As this device has a lower metal mass than conventional stents, it is expected to have a lower rate of ischemic complications and a shorter period with antiplatelet drugs. We experienced in-stent stenosis after endovascular treatment with the PulseRider for a middle cerebral artery aneurysm. A 40-year-old woman with an unruptured aneurysm in the middle cerebral artery bifurcation underwent coil embolization using a PulseRider. The periprocedural course was not problematic, and postoperative angiography showed contrast filling in the aneurysm. The patient was discharged from our hospital on postembolization day 3. However, follow-up angiography after 6 months showed in-stent stenosis. Fortunately, no ischemic complications occurred after treatment. Although the PulseRider is characterized by a low metal mass, it should be noted that this device has some metal markers that can induce in-stent stenosis.

Clinical significance of metastatic tumor deposit foci in rectal cancer in the lateral pelvic lymph node area

BACKGROUND

Although previous studies have demonstrated that tumor deposits (TDs) are associated with worse prognosis in colon cancer, their clinical significance in rectal cancer has not been fully elucidated, especially in the lateral pelvic lymph node (LPLN) area. This study aimed to clarify the clinical significance of TDs, focusing on the number of metastatic foci, including lymph node metastases (LNMs) and TDs, in the LPLN area.

METHODS

This retrospective study involved 226 consecutive patients with cStage II/III low rectal cancer who underwent LPLN dissection. Metastatic foci, including LNM and TD, in the LPLN area were defined as lateral pelvic metastases (LP-M) and were evaluated according to LP-M status: presence (absence vs. presence), histopathological classification (LNM vs. TD), and number (one to three vs. four or more). We evaluated the relapse-free survival of each model and compared them using the Akaike information criterion (AIC) and Harrell's concordance index (c-index).

RESULTS

Forty-nine of 226 patients (22%) had LP-M, and 15 patients (7%) had TDs. The median number of LP-M per patient was one (range, 1-9). The best risk stratification power was observed for number (AIC, 758; c-index, 0.668) compared with presence (AIC, 759; c-index, 0.665) and histopathological classification (AIC, 761; c-index, 0.664). The number of LP-M was an independent prognostic factor for both relapse-free and overall survival, and was significantly associated with cumulative local recurrence.

CONCLUSION

The number of metastatic foci, including LNMs and TDs, in the LPLN area is useful for risk stratification of patients with low rectal cancer.

Oral Administration of Glucosylceramide Suppresses Tumor Growth by Affecting the Ceramide/Sphingosine-1-Phosphate Balance in Breast Cancer Tissue

Background

Ceramide and sphingosine-1-phosphate (S1P) play opposing roles in cell death and survival, and maintain a dynamic balance called the sphingolipid rheostat. Glucosylceramide is a substrate to generate ceramide but its effect on breast cancer by oral administration was never tested. The purpose of this study was to reveal the anticancer activity of glucosylceramide and its potential as a new therapeutic agent in breast cancer.

Methods

E0771 cells were inoculated into the breast tissue of female C57BL/6NJcl mice. Glucosylceramide was administered orally to the mice for nine consecutive days. The concentrations of sphingolipid mediators including ceramide, glucosylceramide, and S1P in tumor tissues and serum were determined by mass spectrometry.

Results

Oral administration of glucosylceramide significantly suppressed E0771 tumor growth compared with the control group (P = 0.006). There were no significant differences in the serum concentrations of sphingolipid mediators including ceramide and S1P between the mice treated with glucosylceramide and control-treated mice. The ceramide concentration was significantly lower in tumor tissues (P = 0.026), and the S1P concentration was significantly higher than that in paired non-tumor tissues (P = 0.009). The S1P concentration in tumor tissues was significantly lower in mice treated with glucosylceramide than in control-treated mice (P = 0.001). The ceramide-to-S1P concentration ratio in tumor tissues was significantly higher in mice treated with glucosylceramide than in control-treated mice (P = 0.034).

Conclusions

Breast tumors could enhance their survival by increasing S1P conversion from ceramide. Oral administration of glucosylceramide suppressed tumor growth by affecting the ceramide/S1P balance. Oral administration of glucosylceramide is a promising basis for a new therapeutic approach.

Rational Extent of Regional Lymphadenectomy and the Prognostic Impact of the Number of Positive Lymph Nodes for Perihilar Cholangiocarcinoma

BACKGROUND

The definition and classification of regional nodes are not standardized for perihilar cholangiocarcinoma. This study aimed to clarify the rational extent of regional lymphadenectomy and to elucidate the impact of number-based regional nodal classification on survival of patients with this disease.

METHODS

Data of 136 patients with perihilar cholangiocarcinoma who underwent surgery were reviewed. The incidence of metastasis and the survival of patients with metastasis were calculated for each node group.

RESULTS

The incidence of metastasis for the node groups in the hepatoduodenal ligament (denoted as no. 12) ranged from 3.7% to 25.4%, with 5-year disease-specific survival of 12.9% to 33.3% for patients with metastasis. The incidences of metastasis in the common hepatic artery (no. 8) and posterior superior pancreaticoduodenal (no. 13a) node groups were 14.4% and 11.2%, respectively, with 5-year disease-specific survival rates of 16.7% and 20.0% for the patients with metastasis. When these node groups were defined as regional nodes, the 5-year disease-specific survival rates for the patients with pN0 (n = 80), pN1 (1-3 positive nodes, n = 38), and pN2 (≥ 4 positive nodes, n = 18) were 61.4%, 22.9%, and 17.6%, respectively (p < 0.001). The pN classification was independently associated with disease-specific survival (p < 0.001). When only the no. 12 node groups were regarded as regional nodes, pN classification failed to stratify the patients prognostically.

CONCLUSIONS

No. 8 and no. 13a node groups should be considered regional nodes in addition to no. 12 node groups and should be dissected. The number-based regional nodal classification allows patients with this disease to be stratified prognostically.

Impact of anatomic resection on long-term survival in patients with hepatocellular carcinoma with T1-T2 disease or microscopic vascular invasion

BACKGROUND

This study aimed to clarify potential candidates for anatomic resection (AR) among patients with pathological T1-T2 (pT1-T2) hepatocellular carcinoma (HCC) and to determine whether AR is effective for HCC with microscopic vascular invasion (MVI).

METHODS

We retrospectively analyzed 288 patients with pT1a (n = 50), pT1b (n = 134) or pT2 (n = 104) HCC who underwent curative-intent resection between 1990 and 2010. Surgical outcomes were compared between patients who underwent AR (n = 189) and those who underwent nonanatomic resection (NAR; n = 99) according to pT category and MVI status.

RESULTS

Patients who underwent AR were more likely to have good hepatic functional reserve and an aggressive primary tumor than those who underwent NAR. When patients were stratified according to pT category, AR had a more favorable impact on survival than NAR only in patients with pT2 HCC in univariate (5-year survival, 51.5% vs. 34.6%; p = 0.010) and multivariate analysis (hazard ratio 0.505; p = 0.014). However, AR had no impact on survival in patients with pT1a or pT1b HCC. In patients with MVI (n = 57), AR achieved better survival than NAR (5-year survival, 52.0% vs. 16.7%; p = 0.019) and was an independent prognostic factor (hazard ratio 0.335; p = 0.020). In patients without MVI (n = 231), there was no significant difference in survival between the two groups (p = 0.221).

CONCLUSION

AR was identified as an independent factor in improved survival in patients with pT2 HCC or HCC with MVI.

Search for the Pair Production of Dark Particles X with K_{L}^{0}→XX, X→γγ

We present the first search for the pair production of dark particles X via K_{L}^{0}→XX with X decaying into two photons using the data collected by the KOTO experiment. No signal was observed in the mass range of 40-110  MeV/c^{2} and 210-240  MeV/c^{2}. This sets upper limits on the branching fractions as B(K_{L}^{0}→XX)<(1-4)×10^{-7} and B(K_{L}^{0}→XX)<(1-2)×10^{-6} at the 90% confidence level for the two mass regions, respectively.

Ulcer Scarring in the Gastric Conduit Is a Risk Factor for Anastomotic Leakage After Esophagectomy for Esophageal Cancer

BACKGROUND

Anastomotic leakage (AL) is a serious complication after esophagectomy for esophageal cancer. The objective of this study was to identify the risk factors for AL.

METHODS

Patients with esophageal cancer who underwent curative esophagectomy and cervical esophagogastric anastomosis between 2009 and 2019 (N = 346) and those between 2020 and 2022 (N = 17) were enrolled in the study to identify the risk factors for AL and the study to assess the association between the risk factors and blood flow in the gastric conduit evaluated by indocyanine green (ICG) fluorescence imaging, respectively.

RESULTS

AL occurred in 17 out of 346 patients (4.9%). Peptic or endoscopic submucosal dissection (ESD) ulcer scars were independently associated with AL (OR 6.872, 95% CI 2.112-22.365) in addition to diabetes mellitus. The ulcer scars in the anterior/posterior gastric wall were more frequently observed in patients with AL than in those without AL (75.0% vs. 17.4%, P = 0.042). The median flow velocity of ICG fluorescence in the gastric conduits with the scars was significantly lower than in those without the scars (1.17 cm/s vs. 2.23 cm/s, P = 0.004).

CONCLUSIONS

Peptic or ESD ulcer scarring is a risk factor for AL after esophagectomy in addition to diabetes mellitus. The scars in the anterior/posterior gastric wall are significantly associated with AL, impairing blood flow of the gastric conduit. Preventive interventions and careful postoperative management should be provided to minimize the risk and severity of AL in patients with these risk factors.

[Radical Resection Followed by Chemotherapy for Intrahepatic Cholangiocarcinoma with Lymph Node Metastases-Report of a Long-Term Survivor]

We report a case of intrahepatic cholangiocarcinoma(ICC)with lymph node metastases in which long-term survival was achieved after surgery followed by chemotherapy. A 69-year-old man underwent left hepatectomy, extrahepatic bile duct resection, and lymph node dissection for ICC located mainly in segment 4 of the liver with enlarged lymph nodes in the hepatoduodenal ligament. The histopathologically confirmed diagnosis was ICC(T2N1M0, Stage ⅣA)with 3 positive lymph nodes(No. 12a1, No. 12p1, and No. 12p2). He received chemotherapy with gemcitabine(GEM)plus cisplatin(CDDP)for 9 months, followed by GEM monotherapy for 4 months, and then S-1 monotherapy was started. A right lung nodule was detected 12 months after the initiation of S-1 monotherapy. He received GEM plus S-1 therapy for 28 months, followed by S-1 monotherapy, leading to disappearance of the lung nodule. He remains alive and well without disease 78 months after surgery. Our experience in this case suggests that radical resection followed by chemotherapy may provide a survival benefit in selected patients who have ICC with nodal disease.

Long-term results of minimally invasive transanal surgery for rectal tumors in 249 consecutive patients

PURPOSE

To delineate the long-term results of minimally invasive transanal surgery (MITAS) for selected rectal tumors.

METHODS

We analyzed data, retrospectively, on consecutive patients who underwent MITAS between 1995 and 2015, to establish the feasibility, excision quality, and perioperative and oncological outcomes of this procedure.

RESULTS

MITAS was performed on 243 patients. The final histology included 142 cancers, 47 adenomas, and 52 neuroendocrine tumors (NET G1). A positive margin of 1.6% and 100% en bloc resection were achieved. The mean operative time was 27.4 min. Postoperative morbidity occurred in 7% of patients, with 0% mortality. The median follow-up was 100 months (up to ≥ 5 years or until death in 91.8% of patients). Recurrence developed in 2.9% of the patients. The 10-year overall survival rate was 100% for patients with NET G1 and 80.3% for those with cancer. The 5-year DFS was 100% for patients with Tis cancer, 90.6% for those with T1 cancer, and 87.5% for those with T2 or deeper cancers. MITAS for rectal tumors ≥ 3 cm resulted in perioperative and oncologic outcomes equivalent to those for tumors < 3 cm.

CONCLUSION

MITAS is feasible for the local excision (LE) of selected rectal tumors, including tumors ≥ 3 cm. It reduces operative time and secures excision quality and long-term oncological outcomes.

[A Case of Unresectable Advanced Gastric Cancer Resected by Conversion Surgery after Trastuzumab Combination Chemotherapy]

A 74-year-old man presented to our hospital with a mass in the left supraclavicular fossa. He was diagnosed with advanced gastric cancer with liver metastasis and left supraclavicular and para-aortic lymph node metastasis, cT3N2M1 (LYM, HEP), cStage Ⅳ(the Union for International Cancer Control, TNM 7th edition). He received a total of 3 courses of S- 1 plus cisplatin therapy. Since he developed adverse reactions such as anorexia, renal dysfunction, and thrombocytopenia and the tumor was HER2-positive, he received 25 courses of capecitabine, cisplatin, and trastuzumab chemotherapy. Three years and 2 months after the first chemotherapy, remarkable tumor reduction was observed. The patient then underwent radical distal gastrectomy with D2 lymphadenectomy, and R0 resection was achieved. The histopathological diagnosis was ypT1aN0M0, ypStage ⅠA. Chemotherapy with trastuzumab may improve the long-term prognosis of HER2-positive Stage Ⅳ gastric cancer if the disease is controlled and radical resection can be achieved.

[Laparoscopic Abdominoperineal Resection for Anal Canal Cancer with Pagetoid Spread]

A woman in her 60s had been aware of perianal erosions for 1 month. Skin biopsy showed Paget's cells in the stratified squamous epithelium, and immunohistochemistry showed negative staining for CK7 and positive staining for CK20. Colonoscopy revealed well-differentiated adenocarcinoma in the anal canal. Computed tomography showed neither regional lymph node metastasis nor distant metastasis. Hence, she was diagnosed with anal canal carcinoma with pagetoid spread. We determined the extent of resection of the skin lesion preoperatively by mapping biopsy, and performed laparoscopic abdominoperineal resection. The pathological findings revealed adenocarcinoma(tub1, tub2), and the skin resection margin was negative. Immunohistochemistry for Paget's cells in the stratified squamous epithelium showed negative staining for GCDFP-15 and CK7, and positive staining for CK20. Twenty-four months after surgery, we detected right inguinal lymph node metastasis and performed right inguinal lymphadenectomy. As of 4 months after the lymphadenectomy, no local recurrence or distant metastasis has been detected during follow-up examinations.

[A Case of Long-Term Survival with Multidisciplinary Treatment after Surgery for Duodenal Cancer with Left Supraclavicular Lymph Node Metastasis]

The patient was a 71-year-old man with a diagnosis of duodenal carcinoma. Abdominal computed tomography(CT) showed no distant metastasis, and he underwent subtotal stomach-preserving pancreaticoduodenectomy. Postoperative adjuvant chemotherapy was not administered. A left supraclavicular lymph node recurrence was detected on CT 15 months after surgery. Capecitabine and oxaliplatin(CAPOX)therapy was administered and the metastatic lesion shrank. Positron emission tomography(PET)-CT showed no lesions at other sites and left cervical lymph node dissection was performed 5 months after the recurrence. Postoperative adjuvant therapy with S-1 was administered for 6 months. However, 2 years and 10 months after the first recurrence, CT showed recurrence in the left supraclavicular lymph node. CAPOX therapy was resumed, but due to an allergic reaction to oxaliplatin, the patient was treated with capecitabine alone. The recurrent lesion was gradually increased in size, and FOLFIRI therapy was introduced. One year and 5 months after secondary recurrence, PET-CT showed that the second recurrent lesion had grown but was confined to the left supraclavicular lymph node, so radiation therapy(60 Gy)to the left neck was performed. The disease was stable for about 10 months and chemotherapy could be discontinued. The lesion increased in size thereafter, and the patient died 7 years after initial surgery.

Advanced Stage Is a Risk for Severe Neutropenia in Breast Cancer Patients Undergoing Neoadjuvant Adriamycin/Cyclophosphamide/Docetaxel Chemotherapy

Background

Severe neutropenia, including febrile neutropenia, is a major toxicity of systemic chemotherapy that leads to delays in treatment, higher costs, and mortality. Severe neutropenia may occur during neoadjuvant chemotherapy even when the patients are free from known risk factors. Pegfilgrastim, a covalent conjugant of filgrastim that stimulate the production of neutrophils, is used for prevention. The current study aimed to reveal the characteristics of patients who need pegfilgrastim for primary prophylaxis to prevent severe neutropenia, including febrile neutropenia and grade 3 neutropenia, during neoadjuvant chemotherapy.

Methods

A retrospective analysis of 83 patients treated with neoadjuvant adriamycin/cyclophosphamide followed by docetaxel chemotherapy was performed. The factors which associated with severe neutropenia were examined by univariate and multivariate analyses.

Results

Severe neutropenia developed in one of 22 patients (5%) with pegfilgrastim for primary prophylaxis and in 17 of 61 patients (28%) without it. In 83 patients, the incidence of severe neutropenia was significantly decreased in the patients with pegfilgrastim for primary prophylaxis shown by the univariate analysis (P = 0.023) and multivariate analysis (P = 0.030). In 61 patients without pegfilgrastim for primary prophylaxis, the univariate analysis showed that severe neutropenia was associated with tumor size (P = 0.004), clinical stage (P = 0.009), and cancer antigen 15-3 (CA15-3) (P = 0.026). The multivariate analysis showed that clinical stage was associated with severe neutropenia (P = 0.021).

Conclusions

The current study demonstrated that advanced stage is a risk for severe neutropenia in patients treated with neoadjuvant adriamycin/cyclophosphamide followed by docetaxel chemotherapy. Given that prophylaxis with pegfilgrastim was associated with significantly lower incidence of severe neutropenia, patient with advance stage breast cancer may benefit from pegfilgrastim during neoadjuvant chemotherapy.

Carotid Artery Stenting for Patients with Radiation-Induced Carotid Artery Stenosis

Objective

In radiation-induced carotid artery stenosis (RIS), morphological characteristics, such as bilateral and long lesion distances and in-stent stenosis, have been reported as common after carotid artery stenting (CAS). Here, we present 25 cases at our hospital wherein CAS was performed for RIS and compare the morphological characteristics and the safety of the treatment with cases of atherosclerotic carotid artery stenosis (AS).

Methods

Twenty-five lesions from 21 patients underwent CAS for RIS at our hospital between March 2002 and July 2020. The procedure was performed at a mean of 10.0 ± 5.2 years after radiation therapy with 60-72 Gy, with a median follow-up of 45 months. We retrospectively selected consecutive patients with AS with comparable follow-up times from the beginning of the study as controls. We compared the patients' background, stenosis findings including plaque MRI, perioperative period, and postoperative course.

Results

All patients in both groups completed the procedure, and the median follow-up time for the RIS and AS groups was 45 and 40 months, respectively (p = 0.1479). Patients in the RIS group had a lower mean age (69.9 ± 6.9 vs. 75.3 ± 7.04, p = 0.0075), a higher stenosis rate (79.1 ± 8.7% vs. 68.6 ± 11.7%, p = 0.0032), and longer stenosis greater than one vertebra (long lesions) (10 vs. 1, p = 0.0046) compared with the patients in the AS group. Although there was no significant difference in outcomes between the two groups, restenosis tended to be more common in the RIS group. Plaque MRI was characterized by a significantly higher T2WI signal (p = 0.0381) in the RIS group, which was attributable to the fact that a necrotic core has been reported commonly in the plaque tissue of RIS.

Conclusion

RIS has a high likelihood of restenosis both morphologically and in terms of plaque characteristics. Thus, close follow-up is crucial.

Differential analysis of microbiomes in mucus and tissues obtained from colorectal cancer patients

The outer mucus layer of the colorectal epithelium is easily removable and colonized by commensal microbiota, while the inner mucus layer is firmly attached to the epithelium and devoid of bacteria. Although the specific bacteria penetrating the inner mucus layer can contact epithelial cells and trigger cancer development, most studies ignore the degree of mucus adhesion at sampling. Therefore, we evaluated whether bacteria adhering to tissues could be identified by removing the outer mucus layer. Our 16S rRNA gene sequencing analysis of 18 surgical specimens of human colorectal cancer revealed that Sutterella (P = 0.045) and Enterobacteriaceae (P = 0.045) were significantly enriched in the mucus covering the mucosa relative to the mucosa. Rikenellaceae (P = 0.026) was significantly enriched in the mucus covering cancer tissues compared with those same cancer tissues. Ruminococcaceae (P = 0.015), Enterobacteriaceae (P = 0.030), and Erysipelotrichaceae (P = 0.028) were significantly enriched in the mucus covering the mucosa compared with the mucus covering cancers. Fusobacterium (P = 0.038) was significantly enriched in the mucus covering cancers compared with the mucus covering the mucosa. Comparing the microbiomes of mucus and tissues with mucus removed may facilitate identifying bacteria that genuinely invade tissues and affect tumorigenesis.

Establishment of the menthol test as a clinical evaluation method for oxaliplatin-induced neuropathy

OBJECTIVES

To determine whether the tongue menthol test, which measures the cold sensation detection threshold (CDT) of the tongue, used before and after oxaliplatin administration is an objective evaluation method for oxaliplatin-induced peripheral neuropathy (OPN).

METHODS

The tongue menthol test was administered to patients both before and after undergoing chemotherapy containing oxaliplatin for colorectal cancer. The tongue menthol test was conducted by applying a menthol solution (a selective agonist of transient receptor potential cation channel subfamily M member 8 [TRPM8]) to the tongue and measuring the CDT.

RESULTS

The mean CDT before the first dose of oxaliplatin was 0.34% (0.005%-1%; n=38), and the mean CDT after the first dose was 0.32% (0.005%-1%; n=38). The CDT appeared to decrease after the first dose, but this difference was not significant. In patients who received five courses of oxaliplatin, changes in CDT values were compared before and after the five courses. In patients with Neurotoxicity Criteria of Debiopharm (DEB-NTC) grade 2 neuropathy, the pre-oxaliplatin administration CDT was compared between before grade exacerbation and when exacerbation occurred, and was found to decline when grade exacerbation occurred. Moreover, when the CDTs before and after administration were compared before grade exacerbation, there was a significant decrease in CDT after administration (P=0.04).

CONCLUSIONS

By performing a menthol test in oxaliplatin-treated patients, it may be possible to objectively predict the exacerbation of peripheral neuropathy at an early stage.

Unveiling microbiome profiles in human inner body fluids and tumor tissues with pancreatic or biliary tract cancer

With the discovery of bacterial symbiosis in the tissues of various cancers, the study of the tumor microbiome is attracting a great deal of attention. Anatomically, since the gastrointestinal tract, liver, and pancreas form a continuous ductal structure, the microbiomes in the digestive juices of these organs may influence each other. Here, we report a series of microbiome data in tumor-associated tissues such as tumor, non-tumor, and lymph nodes, and body fluids such as saliva, gastric juice, pancreatic juice, bile, and feces of patients with pancreatic or biliary tract cancers. The results show that the microbiome of tumor-associated tissues has a very similar bacterial composition, but that in body fluids has different bacterial composition which varies by location, where some bacteria localize to specific body fluids. Surprisingly, Akkermansia was only detected in the bile of patients with biliary tract cancer and its presence was significantly associated with the performance of external biliary drainage (P = 0.041). Furthermore, we found that tumor-associated tissues and body fluids in deep inner body are mostly inhabited by unidentified and uncharacterized bacteria, suggesting that such bacteria may be potential targets for precision therapy in the future.

Utility of autologous fecal microbiota transplantation and elucidation of microbiota in diversion colitis

Objectives

Diversion colitis (DC) is an inflammatory disorder caused by interruption of the fecal stream and subsequent nutrient deficiency from luminal bacteria. The utility of fecal microbiota transplantation (FMT) for DC was recently investigated; however, the precise pathogenesis of this condition remains unclear. This study aimed to evaluate the utility of autologous FMT in DC and to determine the related changes in the intestinal microbiota.

Methods

Autologous FMT was performed to reestablish the intestinal microbiota in five patients (average age, 64.6 ± 8.3 years) with DC. They underwent double‐ended colostomy. We assessed the diverted colon by endoscopy and evaluated the microbiota before and after FMT using the 16S rRNA gene sequencing method.

Results

All five patients had mild inflammation (ulcerative colitis endoscopic index of severity [UCEIS] 2–3) in the diverted colon based on the colonoscopic findings. Three patients presented with symptoms, such as tenesmus, mucoid stool, and bloody stool. With FMT treatment, all patients achieved endoscopic remission (UCEIS score of 0 or 1) and symptomatic improvement. We observed a significantly decreased α‐diversity in DC patients compared to healthy controls. The frequency of aerobic bacteria, such as Enterobacteriaceae, in the diverted colon decreased after autologous FMT.

Conclusions

This study was the first to show that the microbiota in the diverted colon was significantly affected by autologous FMT. Since interruption of the fecal stream is central to the development of DC, FMT can be considered a promising treatment.

Usefulness of laparoscopic right colectomy with intracorporeal anastomosis and preoperative weight reduction for ascending colon cancer in a severely obese patient

Obesity has been considered a risk factor for postoperative complications following colorectal cancer surgery. However, the usefulness of a combination of intracorporeal anastomosis and preoperative weight reduction for severely obese patients with colon cancer remains unclear. A 66-year-old man with a body mass index (BMI) of 43 kg/m² presented with abdominal pain and iron deficiency anemia. Colonoscopy and computed tomography revealed advanced ascending colon cancer with regional lymph node metastasis and excessive abdominal fat. Preoperative diet-induced weight reduction was performed for severe obesity, which decreased his BMI to 39.7 kg/m² after 1 month. Thereafter, curative resection was performed using intracorporeal anastomosis for reconstruction to achieve minimal colon and mesentery mobilization and a shorter incision. The patient was discharged from the hospital without complications. Laparoscopic right hemicolectomy combining intracorporeal anastomosis and preoperative weight reduction was extremely useful in the current patient with severe obesity and ascending colon cancer.

Transarterial embolization for falx dural arteriovenous fistula through the artery of Davidoff and Schechter: A case report

Endovascular transarterial embolization is the standard treatment for the nonsinus-type of dural arteriovenous fistulae. Here, we report a rare case of successful transarterial embolization from the artery of Davidoff and Schechter for falx dural arteriovenous fistulae. A 74-year-old-man was incidentally diagnosed with falx dural arteriovenous fistulae during head magnetic resonance imaging. Results revealed dilatation of the cortical veins in the right occipital lobe. Angiographically, falx dural arteriovenous fistula was observed to be fed by the right middle meningeal artery, right occipital artery, right posterior meningeal artery, and the artery of Davidoff and Schechter (Borden type III). However, due to the tortuosity, the first transarterial embolization surgery through the middle meningeal artery, occipital artery, and posterior meningeal artery was unsuccessful. Therefore, the second transarterial embolization was performed through the artery of Davidoff and Schechter. Arteriovenous fistulae disappeared after administering Onyx injections through the artery of Davidoff and Schechter. Based on our findings, the artery of Davidoff and Schechter can be an approach route to treat dural arteriovenous fistulae. Moreover, the most important point of transarterial embolization procedures through the artery of Davidoff and Schechter is to navigate the microcatheter along the falx.

[Clinical Study of Inguinal Lymph Node Metastasis in Anal Canal Adenocarcinoma]

We reviewed clinical records of 73 cases with anal canal adenocarcinoma who underwent bilateral inguinal lymph node (ILN)dissection. Eleven patients with positive ILN metastasis(ILNM)were compared with 62 patients with negative ILNM in clinicopathological items and treatment outcomes to evaluate the effectiveness of ILN dissection. Positive ILNM were older, higher preoperative serum levels of CEA and CA19-9, more frequencies of undifferentiated carcinoma, T4b and severe lymphatic invasion than negative ILNM. And the number of mesorectal and lateral node metastasis were significantly more in positive ILNM than negative ILNM. Although the frequency of curability A surgery was significantly less in positive ILNM (63.6%)than negative ILNM(93.5%), there were no significant differences in recurrence rate and prognosis between positive ILNM and negative ILNM in Stage Ⅲ cancer. Recurrence in ILN occurred significantly more in positive ILNM (2 cases) than in negative ILNM(0 case)as initial recurrent site. And recurrence in pelvic local site occurred significantly more in positive ILNM(4 cases)than in negative ILNM(6 cases). Although there was no significant difference in oncological outcome in Stage Ⅲ anal canal adenocarcinoma, ILN recurrence and pelvic local recurrence should be cared for positive ILNM in postoperative follow-up.

Prevalence and Risk Factors of Anal and Fecal Incontinence in Japanese Medical Personnel

Objectives

This study aimed to elucidate the actual state of anal incontinence (AI), fecal incontinence (FI), and the associated factors in Japanese medical personnel.

Methods

A questionnaire was completed by Japanese medical personnel after listening to lectures on AI. AI was defined as involuntary loss of feces or flatus.

Results

A total of 463 persons (mean age, 35.6 years; range, 20-91; male/female/no answer, 132/324/7) participated in the questionnaire. AI occurred in 34.4% of 450 participants (flatus/liquid stool/solid stool: 30.4%/3.6%/0.4%). AI was significantly more prevalent in females (male/female: 15.5%/42.7%, p < 0.001). AI and FI occurred significantly more prevalent in participants aged ≧40 years (p < 0.024). AI was significantly associated with childbirth, frequency of childbirth (more than three times), vaginal delivery, urinary incontinence, the style of urination/defecation, and a history of gynecologic surgery and systemic diseases (p < 0.05). Female gender and age as well as urinary incontinence and inability to defecate separately in female and previous colorectal disease and/or surgery in male were risk factors of AI by multivariate analysis (p < 0.05). FI was correlated with urinary incontinence.

Conclusions

AI and FI occurred in 34.4% and 4.0% of Japanese medical personnel, respectively. Gas incontinence was common in every age group. AI was associated with female gender, higher age group, urinary incontinence, the style of urination and defecation in female, and previous colorectal disease and/or surgery in male. FI was associated with urinary incontinence.

Profiling of host genetic alterations and intra-tumor microbiomes in colorectal cancer

Some bacteria are symbiotic in tumor tissues, and metabolites of several bacterial species have been found to cause DNA damage. However, to date, the association between bacteria and host genetic alterations in colorectal cancer (CRC) has not been fully investigated. We evaluated the association between the intra-tumor microbiome and host genetic alterations in 29 Japanese CRC patients. The tumor and non-tumor tissues were extracted from the patients, and 16S rRNA genes were sequenced for each sample. We identified enriched bacteria in tumor and non-tumor tissues. Some bacteria, such as Fusobacterium, which is already known to be enriched in CRC, were found to be enriched in tumor tissues. Interestingly, Bacteroides, which is also known to be enriched in CRC, was enriched in non-tumor tissues. Furthermore, it was shown that certain bacteria that often coexist within tumor tissue were enriched in the presence of a mutated gene or signal pathway with mutated genes in the host cells. Fusobacterium was associated with many mutated genes, as well as cell cycle-related pathways including mutated genes. In addition, the patients with a high abundance of Campylobacter were suggested to be associated with mutational signature 3 indicating failure of double-strand DNA break repairs. These results suggest that CRC development may be partly caused by DNA damage caused by substances released by bacterial infection. Taken together, the identification of distinct gut microbiome patterns and their host specific genetic alterations might facilitate targeted interventions, such as modulation of the microbiome in addition to anticancer agents or immunotherapy.

Histopathological characteristics and artificial intelligence for predicting tumor mutational burden-high colorectal cancer

BACKGROUND

Tumor mutational burden-high (TMB-H), which is detected with gene panel testing, is a promising biomarker for immune checkpoint inhibitors (ICIs) in colorectal cancer (CRC). However, in clinical practice, not every patient is tested for TMB-H using gene panel testing. We aimed to identify the histopathological characteristics of TMB-H CRC for efficient selection of patients who should undergo gene panel testing. Moreover, we attempted to develop a convolutional neural network (CNN)-based algorithm to predict TMB-H CRC directly from hematoxylin and eosin (H&E) slides.

METHODS

We used two CRC cohorts tested for TMB-H, and whole-slide H&E digital images were obtained from the cohorts. The Japanese CRC (JP-CRC) cohort (N = 201) was evaluated to detect the histopathological characteristics of TMB-H using H&E slides. The JP-CRC cohort and The Cancer Genome Atlas (TCGA) CRC cohort (N = 77) were used to develop a CNN-based TMB-H prediction model from the H&E digital images.

RESULTS

Tumor-infiltrating lymphocytes (TILs) were significantly associated with TMB-H CRC (P < 0.001). The area under the curve (AUC) for predicting TMB-H CRC was 0.910. We developed a CNN-based TMB-H prediction model. Validation tests were conducted 10 times using randomly selected slides, and the average AUC for predicting TMB-H slides was 0.934.

CONCLUSIONS

TILs, a histopathological characteristic detected with H&E slides, are associated with TMB-H CRC. Our CNN-based model has the potential to predict TMB-H CRC directly from H&E slides, thereby reducing the burden on pathologists. These approaches will provide clinicians with important information about the applications of ICIs at low cost.

Study of the K_{L}→π^{0}νν[over ¯] Decay at the J-PARC KOTO Experiment

The rare decay K_{L}→π^{0}νν[over ¯] was studied with the dataset taken at the J-PARC KOTO experiment in 2016, 2017, and 2018. With a single event sensitivity of (7.20±0.05_{stat}±0.66_{syst})×10^{-10}, three candidate events were observed in the signal region. After unveiling them, contaminations from K^{±} and scattered K_{L} decays were studied, and the total number of background events was estimated to be 1.22±0.26. We conclude that the number of observed events is statistically consistent with the background expectation. For this dataset, we set an upper limit of 4.9×10^{-9} on the branching fraction of K_{L}→π^{0}νν[over ¯] at the 90% confidence level.

Robotic low anterior resection for rectal cancer with side-to-end anastomosis in a patient with anal stenosis

Background

Colorectal anastomosis using the double stapling technique (DST) has become a standard procedure. However, DST is difficult to perform in patients with anal stenosis because a circular stapler cannot be inserted into the rectum through the anus. Thus, an alternative procedure is required for colorectal anastomosis.

Case presentation

A 78-year-old woman presented with bloody stool. Colonoscopy and computed tomography revealed advanced low rectal cancer without lymph node or distant metastasis. We initially planned to perform low anterior resection using a double stapling technique or transanal hand-sewn anastomosis, but this would have been too difficult due to anal stenosis and fibrosis caused by a Milligan-Morgan hemorrhoidectomy performed 20 years earlier. The patient had never experienced defecation problems and declined a stoma. Therefore, we inserted an anvil into the rectal stump and fixed it robotically with a purse-string suture followed by insertion of the shaft of the circular stapler from the sigmoidal side. In this way, side-to-end anastomosis was accomplished laparoscopically. The distance from the anus to the anastomosis was 5 cm. The patient was discharged with no anastomotic leakage. Robotic assistance proved extremely useful for low anterior resection with side-to-end anastomosis.

Conclusion

Performing side-to-end anastomosis with robotic assistance was extremely useful in this patient with rectal cancer and anal stenosis.

Predicting Potential of Rapid Tumor Growth in Small to Medium Vestibular Schwannomas on the Basis of Sway Assessed Using Posturography

OBJECTIVE

The relationship between quantitative posturography results and growth of vestibular schwannomas (VSs) during conservative management has not been studied. We aimed to clarify the relationship between the presence of disequilibrium based on posturographic measurement and VS growth.

METHODS

This retrospective, single-center study included 53 patients with VSs (Koos stage I or II) managed conservatively after initial diagnosis. Radiographic progression was considered present if 20% volumetric growth was observed over the imaging interval. Posturography was performed at initial diagnosis, and sway velocity (SV) and sway area were calculated. Tumor growth-free survival was estimated using the Kaplan-Meier method.

RESULTS

Mean follow-up period was 2.87 ± 2.58 years, up to tumor growth detection or last follow-up magnetic resonance imaging. Tumor growth incidence was 40.8% and 61.2% at 2 and 5 years, respectively. Cerebellopontine angle extension and SV with eyes open were related to tumor growth. Tumor growth-free survival of patients with cerebellopontine angle extension and patients with intracanalicular tumor at 2 years was 37.3% and 76.4%, respectively. Tumor growth-free survival of patients with SV >2.06 cm/second and patients with SV ≤2.06 cm/second at 2 years was 30.8% and 68.9%, respectively. The Cox hazard model demonstrated a significant risk for future tumor growth with SV >2.06 cm/second (relative risk, 2.475; 95% confidence interval, 1.11-5.37, P = 0.027).

CONCLUSIONS

We demonstrated a positive correlation between SV with eyes open and future tumor growth. Posturographic data are objective and quantitative; thus, SV may be a potential predictor of future growth of VSs.

Evaluation of intestinal microbiota, short-chain fatty acids, and immunoglobulin a in diversion colitis

It is reported that an increase in aerobic bacteria, a lack of short-chain fatty acids (SCFAs), and immune disorders in the diverted colon are major causes of diversion colitis. However, the precise pathogenesis of this condition remains unclear. The aim of the present study was to examine the microbiota, intestinal SCFAs, and immunoglobulin A (IgA) in the diverted colon. Eight patients underwent operative procedures for colostomies. We assessed the diverted colon using endoscopy and obtained intestinal samples from the diverted colon and oral colon in these patients. We analyzed the microbiota and SCFAs of the intestinal samples. The bacterial communities were investigated using a 16S rRNA gene sequencing method. The microbiota demonstrated a change in the proportion of some species, especially Lactobacillus, which significantly decreased in the diverted colon at the genus level. We also showed that intestinal SCFA values were significantly decreased in the diverted colon. Furthermore, intestinal IgA levels were significantly increased in the diverted colon. This study was the first to show that intestinal SCFAs were significantly decreased and intestinal IgA was significantly increased in the diverted colon. Our data suggest that SCFAs affect the microbiota and may play an immunological role in diversion colitis.

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Anaerobic bacteria like Lactobacillus significantly decreased in the diverted colon.

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Fecal short-chain fatty acids significantly decreased in the diverted colon.

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Acetic acid also decreased significantly in the diverted colon.

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Fecal immunoglobulin A levels were significantly increased in the diverted colon.

Predictors of Very Poor Outcome after Mechanical Thrombectomy for Acute Basilar Artery Occlusion

Prognosis for patients with acute basilar artery occlusion (BAO) remains poor. Successful revascularization is a main predictor of favorable clinical outcomes after mechanical thrombectomy for BAO. However, even if mechanical thrombectomy is successful, some patients have a poor clinical outcome, including vegetative state and mortality. This study investigated the factors that are predictive of extremely poor clinical outcomes despite successful revascularization after mechanical thrombectomy for BAO.

We evaluated 35 consecutive patients who presented with acute ischemic stroke due to BAO and who were successfully treated with mechanical thrombectomy. A very poor outcome was defined as a modified Rankin Scale (mRS) score of 5 or 6 at 3 months after treatment. The associations between the clinical, imaging, procedural factors, and poor outcome were evaluated.

Using univariate analyses, there were significant differences in the preoperative National Institute of Health Stroke Scale (NIHSS) score (22.0 ± 9.0 vs. 30.5 ± 4.3, p <0.001), and infarct volume in brain stem (0.11 ± 0.19 cc vs. 2.55 ± 1.56 cc, p <0.001) between the control and very poor outcome groups. In receiver operating characteristic (ROC) curve analysis, the area under ROC curve of infarct volume in brain stem was 0.891 to predict very poor outcome.

Preoperative infarct volume in brain stem is strong predictor for very poor outcome. The infarct volume in brain stem is useful for deciding treatment indications.

Acute ischemic stroke due to internal carotid artery dissection in a 10-year-old child

A 10-year-old girl was transferred to our hospital with left hemiparesis. Diffusion-weighted magnetic resonance imaging (MRI) of the brain showed a signal lesion in the right posterior limb of the internal capsule and magnetic resonance angiography showed poor visualization of the right internal carotid artery (ICA), and a defect area was present in a part of the supraclinoid portion of the right ICA. Based on the clinical and radiological findings, the patient was diagnosed with ischemic stroke due to right ICA dissection (ICAD). She received 5 days of intravenous argatroban followed by oral aspirin. A month later, her hemiparesis markedly improved. As early diagnosis of ICAD is crucial for prompt treatment in children with unexplained gross neurologic abnormalities, this disease should be suspected and MRI should be performed even without a history of blunt trauma to the head and neck.

[A Case of High-Frequency Microsatellite Instability in Colorectal Cancer with MSH2 Mutation Detected Using Gene Panel Testing with a Next-Generation Sequencer]

Here, we report about a woman in her 30s who had peritoneal dissemination and multiple colon cancer with high-frequency microsatellite instability(MSI-H). Her father, paternal grandfather, and maternal grandmother had a history of colorectal cancer treatment. Thus, Lynch syndrome was suspected. We performed R0 resection for peritoneal dissemination and subsequent peritoneal dissemination. A 435-gene panel testing using a next-generation sequencer identified MSH2 and other mutations in the tumor. Hence, we speculated that she could have a germline mutation of MSH2, which causes Lynch syndrome. In the future, if she wishes to receive genetic counseling and undergo germline testing for variants to confirm the diagnosis of Lynch syndrome, we will perform them after receiving informed consent.

RNF43 mutation is associated with aggressive tumor biology along with BRAF V600E mutation in right-sided colorectal cancer

Right-sided colorectal cancer (RCRC) demonstrates worse survival outcome compared with left-sided CRC (LCRC). Recently, the importance of RNF43 mutation and BRAF V600E mutation has been reported in the serrated neoplasia pathway, which is one of the precancerous lesions in RCRC. It was hypothesized that the clinical significance of RNF43 mutation differs according to primary tumor sidedness. To test this hypothesis, the clinicopathological characteristics and survival outcome of patients with RNF43 mutation in RCRC and LCRC were investigated. Stage I–IV CRC patients (n=201) were analyzed. Genetic alterations including RNF43 using a 415-gene panel were investigated. Clinicopathological characteristics between RNF43 wild-type and RNF43 mutant-type were analyzed. Moreover, RNF43 mutant-type was classified according to primary tumor sidedness, i.e., right-sided RNF43 mutant-type or left-sided RNF43 mutant-type, and the clinicopathological characteristics between the two groups were compared. RNF43 mutational prevalence, spectrum and frequency between our cohort and TCGA samples were compared. RNF43 mutation was observed in 27 out of 201 patients (13%). Multivariate analysis revealed that age (≥65), absence of venous invasion, and BRAF V600E mutation were independently associated with RNF43 mutation. Among the 27 patients with RNF43 mutation, 12 patients were right-sided RNF43 mutant-type and 15 left-sided RNF43 mutant-type. Right-sided RNF43 mutant-type was significantly associated with histopathological grade 3, presence of lymphatic invasion, APC wild, BRAF V600E mutation, microsatellite instability-high (MSI-H), and RNF43 nonsense/frameshift mutation compared with left-sided RNF43 mutant-type. Similarly, RNF43 nonsense/frameshift mutations were more frequently observed in RCRC compared with LCRC in the TCGA cohort (P=0.042). Right-sided RNF43 mutant-type exhibited significantly worse overall survival than RNF43 wild-type and left-sided RNF43 mutant-type (P=0.001 and P=0.023, respectively) in stage IV disease. RNF43 mutation may be a distinct molecular subtype which is associated with aggressive tumor biology along with BRAF V600E mutation in RCRC.

Robotic Surgery for Rectal Cancer: Operative Technique and Review of the Literature

The number of patients undergoing robotic surgery for rectal cancer has rapidly increased in Japan, since the government approved the procedure for national insurance coverage in April 2018. Robotic surgery has the potential to overcome some limitations of laparoscopic surgery, especially in the narrow pelvis, providing a three-dimensional view, articulated instruments, and a stable camera platform. Although meta-analyses and randomized controlled trials have failed to demonstrate the superiority of robotic surgery over laparoscopic surgery with respect to the short-term clinical outcomes, the published findings suggest that robotic surgery may be potentially beneficial for patients who are obese, male, or patients undergoing sphincter-preserving surgery for rectal cancer. The safety and feasibility of robotic surgery for lateral lymph node dissection, the standard procedure for locally advanced lower rectal cancer in Japan, have been demonstrated in some retrospective studies. However, additional prospective, randomized trials are required to determine the actual benefits of robotic surgery to ameliorate the urogenital and oncological outcomes. The cost of this approach is a long-standing principal concern. A literature search showed that the cost of robotic surgery for rectal cancer was 1.3-2.5 times higher per patient than that for the laparoscopic approach. We herein describe our surgical technique using a da Vinci Surgical System (S/Si/Xi) with 10 years of experience in performing robotic surgery. We also review current evidence regarding short-term clinical and long-term oncological outcomes, lateral lymph node dissection, and the cost of the procedure.