Introduction of a new surgical robot platform "hinotori™" in an institution with established da Vinci surgery™ for digestive organ operations.

BACKGROUND: New platforms for robotic surgery have recently become available for clinical use; however, information on the introduction of new surgical robotic platforms compared with the da Vinci™ surgical system is lacking. In this study, we retrospectively determined the safe introduction of the new "hinotori™" surgical robot in an institution with established da Vinci surgery using four representative digestive organ operations. METHODS: Sixty-one patients underwent robotic esophageal, gastric, rectal, and pancreatic operations using the hinotori system in our department in 2023. Among these, 22 patients with McKeown esophagectomy, 12 with distal gastrectomy, 11 with high- and low-anterior resection of the rectum, and eight with distal pancreatectomy procedures performed by hinotori were compared with historical controls treated using da Vinci surgery. RESULTS: The console (cockpit) operation time for distal gastrectomy and rectal surgery was shorter in the hinotori group compared with the da Vinci procedure, and there were no significant differences in the console times for the other two operations. Other surgical results were almost similar between the two robot surgical groups. Notably, the console times for hinotori surgeries showed no significant learning curves, determined by the cumulative sum method, for any of the operations, with similar values to the late phase of da Vinci surgery. CONCLUSIONS: This study suggests that no additional learning curve might be required to achieve proficient surgical outcomes using the new hinotori surgical robotic platform, compared with the established da Vinci surgery.

Secure Robotic Transthoracic Valvuloplastic Esophagogastrostomy by Double Flap Technique in Esophagogastric Junctional Cancer Surgery.

Valvuloplastic esophagogastrostomy by the double flap technique (VPEG-DFT) after proximal gastrectomy for early proximal gastric cancer or esophagogastric junctional cancer (EGJC) is a promising procedure to prevent reflux. However, the transhiatal procedure alone for alimentary reconstruction is sometimes too complex because of the short esophageal remnant. Therefore, additional transthoracic procedures are needed in some patients with EGJC. Although additional thoracoscopic surgery has been reported, no reports to date have described robotic transthoracic VPEG-DFT after excision of EGJC. We herein describe the secure robotic techniques of transthoracic VPEG-DFT performed in 3 patients with EGJC. After completion of the abdominal procedures by robotic and extracorporeal creation of H -shaped flaps on the gastric remnant, robotic VPEG-DFT through the right thoracic approach was performed in the prone position. To accomplish VPEG-DFT in the thorax of patients in the prone position, fixation of the esophagus and stomach was performed before the rotation of the 2 organs to expose the planned anastomotic aspect. In addition, the final abdominal phase was required again to prevent a postoperative hiatal hernia. Secure techniques of right transthoracic VPEG-DFT by robotic surgery could contribute to the successful treatment of EGJC when the remnant esophagus is too short.

Three-year outcomes of robotic gastrectomy versus laparoscopic gastrectomy for the treatment of clinical stage I/II gastric cancer: a multi-institutional retrospective comparative study.

BACKGROUND: Oncological benefits of robotic gastrectomy (RG) remain unclear. We aimed to determine and compare the 3-year outcomes of RG and laparoscopic gastrectomy (LG) for the treatment of gastric cancer. METHODS: This was a multi-institutional retrospective study of patients who prospectively underwent RG in a previous study (UMIN000015388) and historical controls who underwent LG. Operable patients with cStage I/II primary gastric cancer were enrolled. The inverse probability of treatment weighting method based on propensity scores was used to balance patient demographic factors and surgeon volume between the RG and LG groups. The primary outcome measure was the 3-year overall survival rate (3yOS). RESULTS: Of the 1,127 patients in the previous study, 326 and 752 patients in the RG and LG groups, respectively, completed the study. The standardized difference of all confounding factors was reduced to 0.09 or less after weighting. In the weighted population, 3yOS was 96.3% and 89.6% in the RG and LG groups, respectively (hazard ratio [HR] 0.34 [0.15, 0.76]; p = 0.009), whereas there was no difference in 3-year recurrence-free survival rate (3yRFS) between the two groups (HR 0.58 [0.32, 1.05]; p = 0.073). Sub-analyses showed that RG improved 3yOS (HR 0.05 [0.01, 0.38]; p = 0.004) and 3yRFS (HR 0.05 [0.01, 0.34]; p = 0.003) in patients with pStage IA disease. Recurrence rates and patterns were similar between the RG and LG groups. RG did not improve the morbidity rate, however, it attenuated some of the adverse events, including anastomotic leakage and intra-abdominal abscess. RG improved estimated blood loss and duration of postoperative hospitalization. CONCLUSION: This study showed surgical and oncological safety of RG for cStage I/II gastric cancer considering the 3-year outcomes, compared with those of LG.

Disturbed passage of jejunal limb near esophageal hiatus after overlapped esophagojejunostomy following laparoscopic total gastrectomy.

BACKGROUND: Overlapped esophagojejunostomy (OEJ) is a secure purely laparoscopic reconstruction after laparoscopic total gastrectomy (LTG). However, long-term surgical results have not been documented well. AIM: In this paper, we report unusual patients who manifested jejunal limb stricture near the esophageal hiatus without anastomotic stenosis during long-term observation after surgery. METHODS: From April 2009 until May 2020, we retrospectively reviewed 211 patients underwent LTG following by OEJ for gastric carcinoma and took a standard surveillance program. We aimed to characterize a novel complicated disorder observed in these patients to assist treatment and prevention. RESULTS: Five patients (2.4%) had unusual jejunal limb stricture after LTG and OEJ, occurring at a mean of 10 mo after initial radical LTG. All five patients had disturbed oral intake and marked weight loss, and two had aspiration pneumonia. Various diagnostic modalities and intraoperative findings in each patient revealed an intact anastomosis, bent or tortuous jejunal limb resulting from loose fibrous adhesions on the left crus at the esophageal hiatus and no cancer recurrence. All five patients were successfully treated by reoperation for adhesiolysis, division of the left crus and rearrangement of the jejunal limb. CONCLUSION: Disturbed passage through the jejunal limb near the hiatus can occur after some types of OEJ following LTG. We speculate that it may result from a short remnant esophagus, excessive mobilization of the jejunal limb that permits bending or tortuosity and adhesions on the left crus at the hiatus. Prevention for this complication is possible during the original LTG procedure.

Initial Learning Curve and Stereotypical Use of Extra Arm During da Vinci Chest Procedures of McKeown Esophagectomy.

Objective: McKeown esophagectomy facilitates extensive lymphadenectomy for the optimal management of esophageal cancer. Robot-assisted esophagectomy (RAE) was introduced in an attempt to reduce the incidence of postoperative complications. The da Vinci System has 3 active robotic arms in addition to the camera scope, and an extra robotic arm (ERA) is generally used to maintain a fine and stable operative field. However, the optimal use of an ERA has not been documented. In addition, the learning curve of the RAE using the da Vinci System remains controversial. In this study, we aimed to determine the optimal use of an ERA in association with the initial learning curve of robotic McKeown esophagectomy with extremely extensive lymphadenectomy. Methods: We reviewed 81 consecutive patients who underwent RAE. To determine whether stereotypical use of an ERA after establishment of its optimal use accounted for the learning curve, we measured the duration of 14 steps and the duration when performed with optimal use of an ERA in the corresponding step by reviewing video-recorded procedures. We then calculated the ratio as the degree of stereotypical use of the ERA during the da Vinci chest procedures. Results: The cumulative sum method showed that the learning curve required 27 cases of RAE. In addition, stereotypical use of the ERA was significantly associated with the learning curve of RAE. Conclusions: Establishment of optimal use of an ERA could help to accelerate the learning curve in da Vinci chest procedures during McKeown esophagectomy with extensive lymphadenectomy.

Safe implementation of robotic gastrectomy for gastric cancer under the requirements for universal health insurance coverage: a retrospective cohort study using a nationwide registry database in Japan.

BACKGROUND: Robotic gastrectomy (RG) has increased since being covered by universal health insurance in 2018. However, to ensure patient safety the operating surgeon and facility must meet specific requirements. We aimed to determine whether RG has been safely implemented under the requirements for universal health insurance in Japan. METHODS: Data of consecutive patients with primary gastric cancer who underwent minimally invasive total or distal gastrectomy-performed by a surgeon certified by the Japan Society for Endoscopic Surgery (JSES) endoscopic surgical skill qualification system (ESSQS) between October 2018 and December 2019-were extracted from the gastrointestinal surgery section of the National Clinical Database (NCD). The primary outcome was morbidity over Clavien-Dindo classification grade IIIa. Patient demographics and hospital volume were matched between RG and laparoscopic gastrectomy (LG) using propensity score-matched analysis (PSM), and the short-term outcomes of RG and LG were compared. RESULTS: After PSM, 2671 patients who underwent RG and 2671 who underwent LG were retrieved (from a total of 9881), and the standardized difference of all the confounding factors reduced to 0.07 or less. Morbidity rates did not differ between the RG and LG patients (RG, 4.9% vs. LG, 3.9%; p = 0.084). No difference was observed in 30-day mortality (RG, 0.2% vs. LG, 0.1%; p = 0.754). The reoperation rate was greater following RG (RG, 2.2% vs. LG, 1.2%; p = 0.004); however, the duration of postoperative hospitalization was shorter (RG, 10 [8-13] days vs. LG, 11 [9-14] days; p < 0.001). CONCLUSIONS: Insurance-covered RG has been safely implemented nationwide.

Postoperative hiatal hernia after minimally invasive esophagectomy for esophageal cancer.

BACKGROUND: Minimally invasive esophagectomy (MIE) can reduce various complications compared with conventional thoracotomic esophagectomy. However, several reports suggested that MIE promoted incidence of post-operative hiatal hernia (HH). In current reports, we retrospectively analyzed incidence and risk factors of HH development after MIE. METHODS: A total of 113 patients undergoing MIE (McKeown esophagectomy) at our institute from April 2009 to December 2015 were included in this study. Patients with clinical stage II and III received neoadjuvant chemotherapy (NAC). RESULTS: Eleven of 113 patients (9.7%) undergoing MIE developed HH. Four of them were female and the ratio of female among the patient with HH was higher than that among the patient without HH after MIE (36.4% vs. 13.7%, P=0.05). Sixty-six patients (58.4%) during the study period were administered NAC and 10 of 11 patients with HH (90.9%) received NAC according to the clinical stage, which was significantly more than in the non-HH group (P=0.02). Type and route of graft organ were not related to HH development. Moreover, the fixation of the conduit organ at the hiatus does not contribute to post-operative HH. CONCLUSIONS: In the current study, we showed that NAC was a major risk factor of HH development after MIE.

Low-dose DNA demethylating therapy induces reprogramming of diverse cancer-related pathways at the single-cell level.

BACKGROUND: Epigenetic reprogramming using DNA demethylating drugs is a promising approach for cancer therapy, but its efficacy is highly dependent on the dosing regimen. Low-dose treatment for a prolonged period shows a remarkable therapeutic efficacy, despite its small demethylating effect. Here, we aimed to explore the mechanisms of how such low-dose treatment shows this remarkable efficacy by focusing on epigenetic reprograming at the single-cell level. METHODS: Expression profiles in HCT116 cells treated with decitabine (DAC) were analyzed by single-cell RNA-sequencing (scRNA-seq). Functional consequences and DNA demethylation at the single-cell level were analyzed using cloned HCT116 cells after DAC treatment. RESULTS: scRNA-seq revealed that DAC-treated cells had highly diverse expression profiles at the single-cell level, and tumor-suppressor genes, endogenous retroviruses, and interferon-stimulated genes were upregulated in random fractions of cells. DNA methylation analysis of cloned HCT116 cells revealed that, while only partial reduction of DNA methylation levels was observed in bulk cells, complete demethylation of specific cancer-related genes, such as cell cycle regulation, WNT pathway, p53 pathway, and TGF-ß pathway, was observed, depending upon clones. Functionally, a clone with complete demethylation of CDKN2A (p16) had a larger fraction of cells with tetraploid than parental cells, indicating induction of cellular senescence due to normalization of cell cycle regulation. CONCLUSIONS: Epigenetic reprogramming of specific cancer-related pathways at the single-cell level is likely to underlie the remarkable efficacy of low-dose DNA demethylating therapy.

Formalin fixation on HER-2 and PD-L1 expression in gastric cancer: A pilot analysis using the same surgical specimens with different fixation times.

BACKGROUND: The needs for human epidermal growth factor receptor 2 (HER-2) and/or programmed death-ligand 1 (PD-L1) evaluations in gastric cancer are dramatically increasing. Although the importance of standardization of sample fixation has been widely recognized, most of the evidence regarding the fixation duration or type of fixing solution are based on breast cancer. AIM: To investigate the real effects of fixation conditions on HER-2 testing or PD-L1 testing for gastric cancer using gastrectomy specimens. METHODS: Thirty-two patients who underwent gastrectomy for gastric cancer were enrolled. Their resected specimens were each divided into four pieces and fixed in four strictly controlled different durations (6 h, 24 h, and 48 h, and 1 wk) by 10% formalin (n = 22) or 10% neutral buffered formalin (NBF) (n = 10). Immunohistochemistry (IHC) of HER-2 and PD-1 was performed, and a pathology examination was conducted. In the HER-2-immunoreactive cases, all four specimens were subjected to dual-color in situ hybridization (DISH). Five cases were assessed as HER-2-positive by IHC and DISH. We used the cut-off values of 1%, 10%, and 50% to assess the IHC findings of PD-L1. RESULTS: No significant difference was observed in comparisons between the shorter fixation period groups (6 h, 24 h, and 48 h) and the prolonged fixation period (1 wk) group in the HER-2 and PD-L1 analyses. Although no significant difference was observed between 10% formalin and 10% NBF within 1 wk of fixation, the superiority of 10% NBF was confirmed in a long-term (> 3 mo) fixation in both the HER-2 and PD-L1 analyses. CONCLUSION: In this small-numbered pilot study, prolonged fixation within 1 wk showed no inferiority in HER-2 or PD-L1 testing. However, a large-numbered prospective study is needed to obtain conclusive results.

Repeated changes of the molecular subtype in gastric metastasis from breast cancer: A case report.

Gastric metastasis from breast cancer is clinically diagnosed rarely. The present study described an interesting and valuable case of gastric metastasis from breast cancer, which showed repeated changes of the molecular subtype with an impact on the choice of treatment. A 42-year-old woman underwent mastectomy with axillary lymph node dissection for an invasive lobular carcinoma of the left breast. The patient received gastroscopy due to an epigastric pain during the adjuvant chemotherapy. The endoscopic examination revealed an erosive lesion at the posterior wall of the gastric body. The gastric lesion was immunohistochemically diagnosed as a metastatic disease from the breast cancer. The patient initially received hormone therapy, according to the subtype of the primary and the metastatic diseases. The gastric lesion initially disappeared; however, a relapsed lesion transformed into luminal human epidermal growth factor receptor 2 type from luminal type. Subsequently, the metastatic lesions underwent repeated subtype changing, which created difficultly when deciding the treatment strategy. The molecular profile of breast cancer can change during the treatment, resulting in the treatment resistance observed in certain cases. Therefore, the optimal treatment must be selected, according to the changed subtype.

Establishment of a DNA methylation marker to evaluate cancer cell fraction in gastric cancer.

BACKGROUND: Tumor samples are unavoidably contaminated with coexisting normal cells. Here, we aimed to establish a DNA methylation marker to estimate the fraction of gastric cancer (GC) cells in any DNA sample by isolating genomic regions specifically methylated in GC cells. METHODS: Genome-wide and gene-specific methylation analyses were conducted with an Infinium HumanMethylation450 BeadChip array and by quantitative methylation-specific PCR, respectively. Purified cancer and noncancer cells were prepared by laser-capture microdissection. TP53 mutation data were obtained from our previous study using next-generation target sequencing. RESULTS: Genome-wide DNA methylation analysis of 12 GC cell lines, 30 GCs, six normal gastric mucosae, one sample of peripheral leukocytes, and four noncancerous gastric mucosae identified OSR2, PPFIA3, and VAV3 as barely methylated in normal cells and highly methylated in cancer cells. Quantitative methylation-specific PCR using 26 independent GCs validated that one or more of them was highly methylated in all of the GCs. Using four pairs of purified cells, we confirmed the three genes were highly methylated (85 % or more) in cancer cells and barely methylated (5 % or less) in noncancer cells. The cancer cell fraction assessed by the panel of the three genes showed good correlation with that assessed by the TP53 mutant allele frequency in 13 GCs (r = 0.77). After correction of the GC cell fraction, unsupervised clustering analysis of the genome-wide DNA methylation profiles yielded clearer clustering. CONCLUSIONS: A DNA methylation marker-namely, the panel of the three genes-is useful to estimate the cancer cell fraction in GCs.

Integrated analysis of cancer-related pathways affected by genetic and epigenetic alterations in gastric cancer.

BACKGROUND: The profiles of genetic and epigenetic alterations in cancer-related pathways are considered to be useful for selection of patients likely to respond to specific drugs, including molecular-targeted and epigenetic drugs. In this study, we aimed to characterize such profiles in gastric cancers (GCs). METHODS: Genetic alterations of 55 cancer-related genes were analyzed by a benchtop next-generation sequencer. DNA methylation statuses were analyzed by a bead array with 485,512 probes. RESULTS: The WNT pathway was activated by mutations of CTNNB1 in 2 GCs and potentially by aberrant methylation of its negative regulators, such as DKK3, NKD1, and SFRP1, in 49 GCs. The AKT/mTOR pathway was activated by mutations of PIK3CA and PTPN11 in 4 GCs. The MAPK pathway was activated by mutations and gene amplifications of ERBB2, FLT3, and KRAS in 11 GCs. Cell-cycle regulation was affected by aberrant methylation of CDKN2A and CHFR in 13 GCs. Mismatch repair was affected by a mutation of MLH1 in 1 GC and by aberrant methylation of MLH1 in 2 GCs. The p53 pathway was inactivated by mutations of TP53 in 19 GCs and potentially by aberrant methylation of its downstream genes in 38 GCs. Cell adhesion was affected by mutations of CDH1 in 2 GCs. CONCLUSIONS: Genes involved in cancer-related pathways were more frequently affected by epigenetic alterations than by genetic alterations. The profiles of genetic and epigenetic alterations are expected to be useful for selection of the patients who are likely to benefit from specific drugs.

Comprehensive DNA methylation and extensive mutation analyses reveal an association between the CpG island methylator phenotype and oncogenic mutations in gastric cancers.

Recent development of personal sequencers for extensive mutation analysis and bead array technology for comprehensive DNA methylation analysis have made it possible to obtain integrated pictures of genetic and epigenetic alterations on the same set of cancer samples. Here, we aimed to establish such pictures of gastric cancers (GCs). Comprehensive methylation analysis of 30 GCs revealed that the number of aberrantly methylated genes was highly variable among individual GCs. Extensive mutation analysis of 55 known cancer-related genes revealed that 19 of the 30 GCs had 24 somatic mutations of eight different genes (CDH1, CTNNB1, ERBB2, KRAS, MLH1, PIK3CA, SMARCB1, and TP53). Integration of information on the genetic and epigenetic alterations revealed that the GCs with the CpG island methylator phenotype (CIMP) tended to have mutations of oncogenes, CTNNB1, ERBB2, KRAS, and PIK3CA. This is one of the first studies in which both genetic and epigenetic alterations were extensively analyzed in the same set of samples. It was also demonstrated for the first time in GCs that the CIMP was associated with oncogene mutations.

Ethanol injection for ablation of an intractable digestive tract fistula: report of a case.

We successfully occluded an intractable digestive tract fistula by injecting it with absolute ethanol after all other treatments failed. A 48-year-old man suffered from a complex and relapsing digestive tract fistula after curative surgery for advanced colon cancer invading the pancreas and duodenum. After conservative management by fasting, drainage, and irrigation failed, fibrin glue infusion achieved only transient occlusion. We performed surgical repair and he was discharged from hospital, at which time fistulography showed no fistula. However, 1 month later fistulography showed that the fistula had recurred and involved the transverse colon, stomach, and intrahepatic bile duct via the jejunum. Finally, we gave five injections of absolute ethanol into the fistula, which resulted in complete occlusion within 6 months. Considering its clinical efficacy, safety, and cost efficiency, we think that ethanol sclerotherapy is a feasible treatment for intractable digestive tract fistula when conservative therapy fails.

Iliac lymph node metastasis of an unknown primary tumor: report of a case.

Metastasis to the lymph nodes around the iliac vessels from cancer of an unknown primary (CUP) tumor has not yet been reported in either the English or Japanese literature and it is therefore described herein for the first time. The patient was a 70-year-old woman with persistent right leg edema. Computed tomography (CT) displayed a mass around the iliac vessels while physical, laboratory, and other imaging examination did not show any other tumor. Preoperatively diagnosed as a retroperitoneal tumor, the patient underwent a tumor resection, but a histopathological examination revealed the tumor to be poorly differentiated squamous cell carcinoma. Only residual lymph nodes in the pelvis were detected by postoperative fluorine-18 fluorodeoxyglucose-positron emission tomography. Neither a primary lesion nor any signs of recurrence were demonstrated for 13 months after radiotherapy for the residual nodes. We herein discuss the diagnosis, treatment, and follow-up of this less common CUP.

The targeted inactivation of polyketide synthase mycAV in the mycinamicin producer, Micromonospora griseorubida, and a complementation study.

Mycinamicin is a 16-membered macrolide antibiotic produced by Micromonospora griseorubida A11725, which shows strong antimicrobial activity against gram-positive bacteria. Recently, the nucleotide sequences of the mycinamicn biosynthetic gene cluster in M. griseorubida have been completely determined. Mycinamicin non-producer M7A21 was isolated by mycAV inactivation, which encodes the module 7 of mycinamicin polyketide synthase (PKS) required for the biosynthesis of the mycinamicin biosynthetic intermediate protomycinolide-IV (PML-IV). When the bioconversion to mycinamicin II (M-II) from PML-IV was performed using M7A21 and the feeding culture method, the productivity of M-II was the same as that of M-II in wild-type strain A11725. p446M7 containing mycAV was constructed using the Escherichia coli-Streptomyces shuttle vector pGM446. The mycinamicin productivity of M7A21 was restored by the introduction of p446M7 into the M7A21 cell, but almost all p446M7 was integrated into the chromosome of M7A21 because the plasmid was unstable in M7A21. The feeding culture and the introduction of the complement gene for M7A21 would be powerful tools to perform combinatorial biosynthesis for the production of new macrolide antibiotics.