Neoadjuvant Chemotherapy Versus Upfront Surgery for Resectable Pancreatic Adenocarcinoma: An Updated Nationwide Study.

OBJECTIVE: The objective of this study was to assess the association of survival with neoadjuvant chemotherapy (NAC) in resectable pancreatic adenocarcinoma (PDAC). BACKGROUND: The early control of potential micrometastases and patient selection using NAC has been advocated for patients with PDAC. However, the role of NAC for resectable PDAC remains unclear. METHODS: Patients with clinical T1 and T2 PDAC were identified in the National Cancer Database from 2010 to 2017. Kaplan-Meier estimates, and Cox regression models were used to compare survival. To address immortal time bias, landmark analysis was performed. Interactions between preoperative factors and NAC were investigated in subgroup analyses. A propensity score analysis was performed to compare survival between multiagent NAC and upfront surgery. RESULTS: In total, 4041 patients were treated with upfront surgery and 1,175 patients were treated with NAC (79.4% multiagent NAC, 20.6% single-agent NAC). Using a landmark time of 6 months after diagnosis, patients treated with multiagent NAC had longer median overall survival compared with upfront surgery and single-agent NAC. (35.8 vs 27.1 vs 27.4 mo). Multiagent NAC was associated with lower mortality rates compared with upfront surgery (adjusted hazard ratio, 0.77; 95% CI, 0.70-0.85), whereas single-agent NAC was not. The association of survival with multiagent NAC were consistent in analyses using the matched data sets. Interaction analysis revealed that the association between multiagent NAC and a lower mortality rate did not significantly differ across age, facility type, tumor location, CA 19-9 levels, and clinical T/N stages. CONCLUSIONS: The findings suggest that multiagent NAC followed by resection is associated with improved survival compared with upfront surgery.

Association between tumor morphology and efficacy of atezolizumab plus bevacizumab for advanced hepatocellular carcinoma.

AIM: The IMbrave150 trial revealed that atezolizumab plus bevacizumab (AtezoBv) showed a higher objective response rate (ORR) in patients with advanced hepatocellular carcinoma (HCC). Although conversion therapy after AtezoBv has been recently reported, markers predictive of its efficacy, particularly radiological imaging markers, have not yet been identified. The present study focused on tumor morphological appearance on radiological imaging and evaluated whether it could be associated with AtezoBv efficacy. METHODS: Ninety-five intrahepatic lesions in 74 patients who were given AtezoBv for advanced HCC were recruited for evaluation. The lesions were divided into two groups, simple nodular (SN group) and non-simple nodular (non-SN group), based on the gross morphology on pretreatment imaging, and retrospectively evaluated for treatment response and other relevant clinical outcomes. RESULTS: Assessing the size of individual tumors after treatment, waterfall plots showed that tumor shrinkage in the non-SN group including 56 lesions was higher than that in the SN group comprising 39 lesions. The ORR was significantly higher in the non-SN group (39.3% vs. 15.4%, p = 0.012). Additionally, the median time to nodular progression was longer in the non-SN group (21.0 months vs. 8.1 months, p = 0.119) compared to the SN group. Six patients with non-SN lesions underwent sequential local therapy. CONCLUSIONS: Atezolizumab plus bevacizumab may show increased therapeutic efficacy in patients with tumors with a higher potential for aggressive oncological behavior, such as non-SN lesions. Treatment strategies focusing on conversion therapy may be crucial in patients with non-SN lesions.

Optimal cutoff values of drain amylase for predicting pancreatic fistula are different between open and laparoscopic distal pancreatectomy.

BACKGROUND: Drainage fluid amylase (DFA) is useful for predicting clinically relevant postoperative pancreatic fistula (CR-POPF) after distal pancreatectomy (DP). However, difference in optimal cutoff value of DFA for predicting CR-POPF between open DP (ODP) and laparoscopic DP (LDP) has not been investigated. This study aimed to identify the optimal cutoff values of DFA for predicting CR-POPF after ODP and LDP. METHODS: Data for 294 patients (ODP, n = 127; LDP, n = 167) undergoing DP at Kobe University Hospital between 2010 and 2021 were reviewed. Propensity score matching was performed to minimize treatment selection bias. Receiver operating characteristic (ROC) analysis was performed to determine the optimal cutoff values of DFA for predicting CR-POPF for ODP and LDP. Logistic regression analysis for CR-POPF was performed to investigate the diagnostic value of DFA on postoperative day (POD) three with identified cutoff value. RESULTS: In the matched cohort, CR-POPF rates were 24.7% and 7.9% after ODP and LDP, respectively. DFA on POD one was significantly lower after ODP than after LDP (2263 U/L vs 4243 U/L, p < 0.001), while the difference was not significant on POD three (543 U/L vs 1221 U/L, p = 0.171). ROC analysis revealed that the optimal cutoff value of DFA on POD one and three for predicting CR-POPF were different between ODP and LDP (ODP, 3697 U/L on POD one, 1114 U/L on POD three; LDP, 10564 U/L on POD one, 6020 U/L on POD three). Multivariate analysis showed that DFA on POD three with identified cutoff value was the independent predictor for CR-POPF both for ODP and LDP. CONCLUSIONS: DFA on POD three is an independent predictor for CR-POPF after both ODP and LDP. However, the optimal cutoff value for it is significantly higher after LDP than after ODP. Optimal threshold of DFA for drain removal may be different between ODP and LDP.

Impact of bile leak on the prognosis of patients with hepatocellular carcinoma who have undergone liver resection.

PURPOSE: The impact of postoperative bile leak on the prognosis of patients with hepatocellular carcinoma who underwent liver resection is controversial. This study aimed to investigate the prognostic impact of bile leak for patients with hepatocellular carcinoma who underwent liver resection. METHODS: Patients with hepatocellular carcinoma who underwent liver resection between 2009 and 2019 at Kobe University Hospital and Hyogo Cancer Center were included. After propensity score matching between the bile leak and no bile leak groups, differences in 5-year recurrence-free and overall survival rates were evaluated using the Kaplan-Meier method. RESULTS: A total of 781 patients, including 43 with postoperative bile leak, were analyzed. In the matched cohort, 40 patients were included in each group. The 5-year recurrence-free survival rates after liver resection were 35% and 32% for the bile leak and no bile leak groups, respectively (P = 0.857). The 5-year overall survival rates were 44% and 54% for the bile leak and no bile leak groups, respectively (P = 0.216). CONCLUSION: Overall, bile leak may not have a profound negative impact on the prognosis of patients with hepatocellular carcinoma who have undergone liver resection.

Comparison of laparoscopic liver resection for the ventral versus the dorsal areas of segment 8.

PURPOSE: The technical difficulties of laparoscopic liver resection (LLR) are greatly associated with the location of liver tumors. Since segment 8 (S8) contains a wide area, the difficulty of LLR for S8 tumors may vary depending on the location within the segment, such as the ventral (S8v) and dorsal (S8d) area, but the difference is unclear. METHODS: We retrospectively investigated 30 patients who underwent primary laparoscopic partial liver resection for liver tumors in S8 at Kobe University Hospital between January 2018 and June 2023. RESULTS: Thirteen and 17 patients underwent LLR for S8v and S8d, respectively. The operation time was significantly longer (S8v 203[135-259] vs. S8d 261[186-415] min, P = 0.002) and the amount of blood loss was significantly higher (10[10-150] vs. 10[10-200] mL, P = 0.034) in the S8d group than in the S8v group. No significant differences were observed in postoperative complications or postoperative length of hospital stay. Additionally, intraoperative findings revealed that the rate at which the case performed partial liver mobilization in the S8d group was higher (2[15.4%] vs. 8[47.1%], P = 0.060) and the median parenchymal transection time of the S8d group was longer (102[27-148] vs. 129[37-175] min, P = 0.097) than those in the S8v group, but there were no significant differences. CONCLUSION: The safety of LLR for the S8d was comparable to that of LLR for S8v, although LLR for S8d resulted in longer operative time and more blood loss. THE TRIAL REGISTRATION NUMBER: B230165 (approved at December 26, 2023).

Prevalence and progression of intraductal papillary mucinous neoplasms of the pancreas in solid organ transplant recipients: A systematic review.

Solid organ transplantation (SOT) recipients are known to carry an increased risk of malignancy because of long-term immunosuppression. However, the progression of intraductal papillary mucinous neoplasm of the pancreas (IPMN) in this population remains unclear. We performed a systematic review by searching PubMed, Embase, Scopus, and Google Scholar. All studies containing IPMNs in solid organ transplantation recipients were screened. We included 11 studies in our final analysis, totaling 274 patients with IPMNs of the 8213 SOT recipients. The prevalence from 8 studies was 4.7% (95% CI 2.4%-7.7%) in a random-effects model with median study periods of 24 to 220 months. The median rate for all progressions from 10 studies was 20% (range, 0%-88%) within 13 to 41 months of the median follow-up time. By utilizing the results of 3 case-control studies, the relative risk from a random-effects model for progression (worrisome features and high-risk stigmata) of IPMNs was 0.39 (95% CI 0.12-1.31). No adenocarcinoma derived from IPMN was reported in the included studies. Overall, this study indicates that the progression of pretransplant IPMN does not increase drastically compared with the general nontransplant population. However, considering the limited literature, further studies are required for confirmation.

Risk Factors for Recurrence of Cholangitis After Pancreaticoduodenectomy and Comparison of Stents in Hepaticojejunostomy.

BACKGROUND: Postoperative cholangitis is a common complication of pancreaticoduodenectomy. Frequent cholangitis impairs patients' quality of life after pancreaticoduodenectomy. However, the risk factors for recurrence of cholangitis remain unclear. Hence, this retrospective study aimed to identify risk factors for recurrence of cholangitis after pancreaticoduodenectomy. METHODS: The medical records of patients who underwent pancreaticoduodenectomy between 2015 and 2019 in our institution were retrospectively reviewed. At least two episodes of cholangitis a year after pancreaticoduodenectomy were defined as 'recurrence of cholangitis' in the present study. Univariate and multivariate analyses were performed. RESULTS: The recurrence of cholangitis occurred in 40 of 207 patients (19.3%). Multivariate analysis revealed that internal stent (external, RR: 2.16, P = 0.026; none, RR: 4.76, P = 0.011), firm pancreas (RR: 2.61, P = 0.021), constipation (RR: 3.49, P = 0.008), and postoperative total bilirubin>1.7 mg/dL (RR: 2.94, P = 0.006) were risk factors of recurrence of cholangitis. Among patients with internal stents (n = 54), those with remnant stents beyond 5 months had more frequent recurrence of cholangitis (≥5 months, 75%; <5 months, 30%). CONCLUSIONS: Internal stents, firm pancreas, constipation, and postoperative high bilirubin levels are risk factors for cholangitis recurrence after pancreaticoduodenectomy. In addition, the long-term implantation of internal stents may trigger cholangitis recurrence.

Use of a short cartridge stapler is beneficial in pancreatic transection at the neck during laparoscopic distal pancreatectomy.

Stapling is the standard method for pancreatic transection during laparoscopic distal pancreatectomy. Although most surgeons use a 60 mm cartridge stapler, space limitations created by laparoscopic surgery make the instrument difficult to handle, especially during pancreatic transection at the neck. Therefore, we currently use a 45 mm cartridge stapler for laparoscopic pancreatic transection at the neck. Between October 2019 and December 2020, we performed pancreatic transection using a 45 mm cartridge stapler in 27 patients. Fifteen patients experienced biochemical leakage, but no patients developed clinically relevant pancreatic fistula. The compactness of the 45 mm cartridge has several benefits: (1) less space is required for flexing, opening, and closing the device; (2) it enables easy insertion of the lower jaw behind the pancreas, even if the dissected space behind the pancreas is narrow; (3) less obstruction of the surgeons' view prevents accidental injury to the surrounding tissues and vessels. These benefits may enable safe pancreatic transection.

Transarterial chemoembolization for liver metastases of a pancreatic neuroendocrine neoplasm: a single-center experience.

Transarterial chemoembolization (TACE) is performed for pancreatic neuroendocrine tumor (PanNEN) liver metastases; however, the safety and efficacy of TACE procedures, especially for patients who have undergone previous pancreatic surgery, have not been established. We reviewed 48 TACE procedures (1-6 procedures/patient) performed on 11 patients with PanNEN liver metastases, including 16 TACE procedures (4-6 procedures/patient) for 3 patients with a history of biliary-enteric anastomosis. The overall tumor objective response rate was 94%. The incidence of Clavien‒Dindo grade ≥ 2 complications was 1/16 (6%) and 1/32 (3%), and the median time to untreatable progression was 31 (14-41) and 27 (2-60) months among patients with and without a history of biliary-enteric anastomosis, respectively. Although validation is needed in future studies, our experiences have shown that TACE treatment is a viable treatment option for PanNEN liver metastases, even after biliary-enteric anastomosis with experienced teams and careful patient follow-up.

[A Case of Ampullary Carcinoma with Celiac Axis Stenosis That Underwent Pancreaticoduodenectomy and Arterial Reconstruction].

A 72-year-old male patient presented with obstructive jaundice and was diagnosed with ampullary carcinoma. Contrast- enhanced computed tomography(CT)showed stenosis of the common hepatic artery and dilatation of the pancreaticoduodenal arcade(PDA)due to celiac axis stenosis(CAS)at the origin, suggesting that hepatic artery blood flow was supplied from the superior mesenteric artery via the PDA. Since calcification of the arterial wall was observed at the origin of the celiac artery(CA), the cause of the CAS was diagnosed as atherosclerotic. An intraoperative gastroduodenal artery(GDA) clamp test showed no obvious decrease in hepatic arterial blood flow. However, because of concerns about the postoperative patency of the CA, an inferior pancreaticoduodenal artery-GDA bypass using the left great saphenous vein and subtotal stomach-preserving pancreaticoduodenectomy were performed. The postoperative course was uneventful. When pancreaticoduodenectomy is performed in patients with atherosclerotic CAS, this arterial reconstruction method can be considered as an option.

Fiducial marker position affects target volume in stereotactic lung irradiation.

PURPOSE: Real-time tracking systems of moving respiratory targets such as CyberKnife, Radixact, or Vero4DRT are an advanced robotic radiotherapy device used to deliver stereotactic body radiotherapy (SBRT). The internal target volume (ITV) of lung tumors is assessed through a fiducial marker fusion using four-dimensional computed tomography (CT). It is important to minimize the ITV to protect normal lung tissue from exposure to radiation and the associated side effects post SBRT. However, the ITV may alter if there is a change in the position of the fiducial marker with respect to the tumor. This study investigated the relationship between fiducial marker position and the ITV in order to prevent radiation exposure of normal lung tissue, and correct target coverage. MATERIALS AND METHODS: This study retrospectively reviewed 230 lung cancer patients who received a fiducial marker for SBRT between April 2015 and September 2021. The distance of the fiducial marker to the gross tumor volume (GTV) in the expiratory (dex ) and inspiratory (din ) CT, and the ratio of the ITV/V(GTVex ), were investigated. RESULTS: Upon comparing each lobe, although there was no significant difference in the ddiff and the ITV/V(GTVex ) between all lobes for dex  < 10 mm, there was significant difference in the ddiff and the ITV/V(GTVex ) between the lower and upper lobes for dex ≥ 10 mm (p < 0.05). Moreover, there was significant difference in the ddiff and the ITV/V(GTVex ) between dex ≥10 mm and dex  < 10 mm in all lung regions (p < 0.05). CONCLUSION: The ITV that had no margin from GTVs increased when dex was ≥10 mm for all lung regions (p < 0.05). Furthermore, the increase in ITV tended to be greater in the lower lung lobe. These findings can help decrease the possibility of adverse events post SBRT, and correct target coverage.

[Laparoscopic Distal Pancreatectomy for Pancreatic Metastasis of Undifferentiated Pleomorphic Sarcoma-A Case Report].

Undifferentiated pleomorphic sarcoma(UPS)is a non-epithelial malignant tumor with a high rate of recurrence and metastasis. The frequent metastasis site is lung, lymph node, liver and bone. Pancreatic metastasis is rare. 71-year-old woman whose course after right foot UPS resection had been followed up at our hospital. But multiple bone and muscle metastasis occurred 1 year after operation. She had resection or radiation for the recurrence. 3 years after the first operation, PET-CT and EUS-FNA revealed pancreatic tail metastasis. The tumor grew up in 6 months, so we performed laparoscopic distal pancreatectomy. The patient recovered uneventfully and was discharged on post-operative day 14. Currently 5 years and 6 months have passed since the first surgery and she is alive. Function-preserving and minimally invasive surgery for UPS pancreatic metastasis is considered to be essential.

Influence of the Retrocolic Versus Antecolic Route for Alimentary Tract Reconstruction on Delayed Gastric Emptying After Pancreatoduodenectomy: A Multicenter, Noninferiority Randomized Controlled Trial.

OBJECTIVE: This study aimed to determine whether retrocolic alimentary tract reconstruction is noninferior to antecolic reconstruction in terms of DGE incidence after pancreatoduodenectomy (PD) and investigated patients' postoperative nutritional status. SUMMARY OF BACKGROUND DATA: The influence of the route of alimentary tract reconstruction on DGE after PD is controversial. METHODS: Patients from 9 participating institutions scheduled for PD were randomly allocated to the retrocolic or antecolic reconstruction groups. The primary outcome was incidence of DGE, defined according to the 2007 version of the International Study Group for Pancreatic Surgery definition. Noninferiority would be indicated if the incidence of DGE in the retrocolic group did not exceed that in the antecolic group by a margin of 10%. Patients' postoperative nutrition data were compared as secondary outcomes. RESULTS: Total, 109 and 103 patients were allocated to the retrocolic and antecolic reconstruction group, respectively (n = 212). Baseline characteristics were similar between both groups. DGE occurred in 17 (15.6%) and 13 (12.6%) patients in the retrocolic and antecolic group, respectively (risk difference; 2.97%, 95% confidence interval; -6.3% to 12.6%, which exceeded the specified margin of 10%). There were no differences in the incidence of other postoperative complications and in the duration of hospitalization. Postoperative nutritional indices were similar between both groups. CONCLUSIONS: This trial could not demonstrate the noninferiority of retrocolic to antecolic alimentary tract reconstruction in terms of DGE incidence. The alimentary tract should not be reconstructed via the retrocolic route after PD, to prevent DGE.

[A Patient with Ascending Jejunal Mesentery Metastasis of Pancreatic Cancer after a Subtotal Stomach-Preserving Pancreaticoduodenectomy].

A 73-year-old woman underwent a subtotal stomach-preserving pancreaticoduodenectomy, wedge resection of the portal vein, and partial resection of the transverse colon for pancreatic cancer at the age of 71. After 18 months, a computed tomography image showed an 8 mm tumor in the ascending jejunal mesentery. Six months later, the tumor grew to 20 mm and had an increased FDG uptake. The tumor was diagnosed as metastasis of pancreatic cancer to the ascending jejunal mesentery. Since no metastasis was found in the other organs, resection was performed. The pathological results showed adenocarcinoma with proximal lymph node metastasis. The patient was diagnosed with ascending jejunal mesentery metastasis of pancreatic cancer. The patient has remained healthy without recurrent disease 1 year 6 months after the resection. Ascending jejunal mesentery metastasis of pancreatic cancer is a type of distant metastasis. In the absence of metastasis to other organs, it is tolerable and radical resection is possible.

[A Case of Pancreatic Cancer with Gastric Wall Recurrence after Laparoscopic Distal Pancreatectomy Due to Needle Tract Seeding following EUS-FNA].

A woman in her 80s was diagnosed with pancreatic tail cancer by endoscopic ultrasound-guided fine needle aspiration (EUS-FNA). We performed laparoscopic distal pancreatectomy followed by adjuvant chemotherapy with S-1 for 6 months. One year after surgery, contrast-enhanced computed tomography revealed a 15 mm mass in the posterior wall of the gastric body. EUS showed a hypoechoic mass in the muscular layer in the gastric wall, which was diagnosed as adenocarcinoma by FNA. We diagnosed gastric wall recurrence due to needle tract seeding(NTS)following EUS-FNA and performed partial gastrectomy. Histopathological diagnosis was gastric wall recurrence of pancreatic cancer. Since NTS following EUS-FNA can be proven only by the presence of gastric wall recurrence after surgery for pancreatic body or tail cancer, the actual risk of NTS including peritoneal dissemination is not clear and may have been underestimated. In case of resectable pancreatic body or tail cancer, indication for EUS-FNA should be carefully considered.

Direct adjustment for confounding by smoking reduces radiation-related cancer risk estimates of mortality among male nuclear workers in Japan, 1999-2010.

A causal relationship between protracted exposure to low-dose rate radiation and health effects remains unclear despite extensive international studies of nuclear workers. One potential reason is that radiation epidemiological studies that adjust for tobacco smoking, which heavily influences mortality, have been limited. In the present study, we examined radiation-related cancer risk by directly assessing the possible confounding effect of smoking, using data from two questionnaire surveys performed among Japanese nuclear workers in 1997 and 2003. Mortality follow-up was carried out for 71 733 male respondents for an average of 8.2 years during the observation period of 1999-2010. The mean cumulative dose was 25.5 mSv at the end of the follow-up period. Estimates of excess relative risk per Sv (ERRs/Sv) were obtained by Poisson regression. By adjusting for smoking directly on the basis of a linear dose-response model, we quantified the confounding effects of smoking on radiation risks. Statistically significant ERRs/Sv were found for all causes, all diseases, all non-cancer diseases, and liver cancer: 0.97 (90% confidence interval: 0.23, 1.78), 1.32 (0.40, 2.34), 1.87 (0.47, 3.49), and 4.78 (0.09, 11.68), respectively, without adjustment for smoking. However, the ERRs/Sv were no longer statistically significant after adjustment for smoking: 0.45 (-0.22, 1.19), 0.77 (-0.08, 1.72), 1.28 (-0.03, 2.79), and 3.89 (-0.46, 10.34), respectively. The ERRs/Sv for all cancers excluding leukaemia and lung cancer were not significant before adjustment for smoking, but declined after adjustment for smoking. The present study demonstrates that in this cohort of workers, smoking heavily distorts radiation risk estimates of mortality. The possibility of confounding by smoking depends on how strongly smoking is correlated with radiation exposure. If a correlation between smoking and radiation dose is suggested, smoking is an important confounder when assessing the radiation and health risks.

Corrigendum: direct adjustment for confounding by smoking reduces radiation-related cancer risk estimates of mortality among male nuclear workers in Japan, 1999-2010.

We found some trivial errors which might confuse reader. The errors can be identified as the following two types. (1) The one is that misuse of "ERR" and "ERR/Sv". We denoted "Table 4 shows ERRs/Sv and 90% CIs ..." in line 7 of page 366. While we denoted "ERR and 90% CI for all cancers, excluding leukaemia, by dose category ..." in title of Table 4. The values described in Table 4 were ERR by dose category and not ERR/Sv. In addition, the explanation about the model that derived ERR by dose category is better to be added. Therefore, the description mentioned above should be changed as follows. (Misprinted) Table 4 shows ERRs/Sv and 90% CIs for all cancers excluding leukaemia by dose category. (Corrected) Table 4 shows ERRs which were defined as follow equation and 90% CIs for all cancers excluding leukaemia by dose category. λ=λ0 (a,c,y,r,s)exp(α1z1+α2z2+α3z3) (1+ßi di) where di is the dose category, and ßi is the ERR by dose category. The lowest dose category was set as reference. (2) The other were errors in surface caput of several tables. We described "ERR without adjustment for smoking" and "ERR with adjustment for smoking" in Table 4. These are correct description. However, "ERR with adjustment for smoking" was described as "For smoking" in Table 2. In addition, "Without adjustment" and "With adjustment" denoted in the surface caput of Table 5, 6, 7 should be denoted as "Without adjustment for smoking" and "With adjustment for smoking". The author wishes to apologies for the errors. .

[A Patient with Multiple Pancreatic Metastases Undergoing Total Pancreatectomy 18 Years after Renal Cell Carcinoma Resection].

A 71-year-old woman underwent right nephrectomy for the treatment of clear cell renal cell carcinoma at the age of 53. After 15 years, surgical removal of a solitary tumor was performed in the right adrenal gland and thyroid gland; both were diagnosed as metastases of renal cell carcinoma. Eighteen years after the initial resection, computed tomography(CT) showed multiple hypervascular tumors spreading across the entire area of the pancreas. She was referred to our hospital, and endoscopic ultrasound-guided fine needle aspiration biopsy(EUS-FNA)revealed that they were metastases from the renal cell carcinoma. Total pancreatectomy and splenectomy were performed, and the patient remains alive and well with no evidence of recurrent disease 7 months after the pancreatectomy. Furthermore, her blood glucose level is well controlled with insulin therapy.

A Circularly Arranged Sextuple Triptycene Gear Molecule.

Herein we report the synthesis of a circularly arranged sextuple triptycene gear molecule, hexakis(10-dodecyloxy-9-triptycyl)ethynylbenzene, via the trimerization of the corresponding triyne with a cobalt catalyst. The six triptycene gears are closely engaged with each other as confirmed by single crystal X-ray structure analysis, and their motion in solution was established by NMR spectroscopy. Notably, when one bulky RuCp* complex was attached to one triptycene gear, the whole movement of the six gears was highly restricted via their mechanical engagement. Development of such a multigear molecule would provide a structural basis for molecular motion transmission systems with a switching function.