Ductal adenocarcinoma of the pancreatic head: A focus on current diagnostic and surgical concepts

Are Osteoclasts Mechanosensitive Cells?

Skeleton metabolism is a process in which osteoclasts constantly remove old bone and osteoblasts form new osteoid and induce mineralization; disruption of this balance may cause diseases. Osteoclasts play a key role in bone metabolism, as osteoclastogenesis marks the beginning of each bone remodeling cycle. As the only cell capable of bone resorption, osteoclasts are derived from the monocyte/macrophage hematopoietic precursors that terminally adhere to mineralized extracellular matrix, and they subsequently break down the extracellular compartment. Bone is generally considered the load-burdening tissue, bone homeostasis is critically affected by mechanical conductions, and the bone cells are mechanosensitive. The functions of various bone cells under mechanical forces such as chondrocytes and osteoblasts have been reported; however, the unique bone-resorbing osteoclasts are less studied. The oversuppression of osteoclasts in mechanical studies may be because of its complicated differentiation progress and flexible structure, which increases difficulty in targeting mechanical structures. This paper will focus on recent findings regarding osteoclasts and attempt to uncover proposed candidate mechanosensing structures in osteoclasts including podosome-associated complexes, gap junctions and transient receptor potential family (ion channels). We will additionally describe possible mechanotransduction signaling pathways including GTPase ras homologue family member A (RhoA), Yes-associated protein/transcriptional co-activator with PDZ-binding motif (TAZ), Ca²⁺ signaling and non-canonical Wnt signaling. According to numerous studies, evaluating the possible influence of various physical environments on osteoclastogenesis is conducive to the study of bone homeostasis.

Biliary Tract Carcinogenesis Model Based on Bile Metaproteomics

Purpose: To analyze human and bacteria proteomic profiles in bile, exposed to a tumor vs. non-tumor microenvironment, in order to identify differences between these conditions, which may contribute to a better understanding of pancreatic carcinogenesis.

Patients and Methods: Using liquid chromatography and mass spectrometry, human and bacterial proteomic profiles of a total of 20 bile samples (7 from gallstone (GS) patients, and 13 from pancreatic head ductal adenocarcinoma (PDAC) patients) that were collected during surgery and taken directly from the gallbladder, were compared. g:Profiler and KEGG (Kyoto Encyclopedia of Genes and Genomes) Mapper Reconstruct Pathway were used as the main comparative platform focusing on over-represented biological pathways among human proteins and interaction pathways among bacterial proteins.

Results: Three bacterial infection pathways were over-represented in the human PDAC group of proteins. IL-8 is the only human protein that coincides in the three pathways and this protein is only present in the PDAC group. Quantitative and qualitative differences in bacterial proteins suggest a dysbiotic microenvironment in the PDAC group, supported by significant participation of antibiotic biosynthesis enzymes. Prokaryotes interaction signaling pathways highlight the presence of zeatin in the GS group and surfactin in the PDAC group, the former in the metabolism of terpenoids and polyketides, and the latter in both metabolisms of terpenoids, polyketides and quorum sensing. Based on our findings, we propose a bacterial-induced carcinogenesis model for the biliary tract.

Conclusion: To the best of our knowledge this is the first study with the aim of comparing human and bacterial bile proteins in a tumor vs. non-tumor microenvironment. We proposed a new carcinogenesis model for the biliary tract based on bile metaproteomic findings. Our results suggest that bacteria may be key players in biliary tract carcinogenesis, in a long-lasting dysbiotic and epithelially harmful microenvironment, in which specific bacterial species' biofilm formation is of utmost importance. Our finding should be further explored in future using in vitro and in vivo investigations.

Higher body mass index deteriorates postoperative outcomes of pancreaticoduodenectomy

BACKGROUND

Previous studies presented controversies in impact of body mass index (BMI) on perioperative complications in pancreatectomy, and mainly focused on Western population. This study aimed to explore the impact of BMI on perioperative outcomes in Chinese patients undergoing pancreaticoduodenectomy.

METHODS

Seven hundred and seven adult patients undergoing open pancreaticoduodenectomy between January 2005 and December 2016 at Ruijin Hospital were studied retrospectively and categorized as obese (BMI ≥25 kg/m²), overweight (BMI ≥23 kg/m² and <25 kg/m²), or normal weight (BMI ≥18.5 kg/m² and <23 kg/m²). Associations of these BMI groups with perioperative outcomes were evaluated.

RESULTS

The overweight and obese groups experienced higher risk of clinically related postoperative pancreatic fistula (CR-POPF) (7.6% vs. 9.9% vs. 17.6%, P = 0.002) and re-operation (1.1% vs. 2.5%  vs. 5.1%, P = 0.017), and longer systemic inflammation response syndrome (SIRS) duration [2 (1-9) d vs. 2 (1-7) d vs. 3 (1-10) d, P = 0.003] and postoperative hospital stay [19 (2-84) d vs. 19 (7-158) d vs. 23 (8-121) d, P = 0.023] than the normal weight group did. The multiple logistic regression models showed obese as an independent risk factor for CR-POPF (P = 0.013). The multiple linear regression analysis confirmed BMI as a predictor for prolonged postoperative hospital stay (P = 0.005).

CONCLUSIONS

Higher BMI results in higher morbidity of Chinese patients undergoing open pancreaticoduodenectomy. Pancreaticoduodenectomy is still a safe surgery procedure for overweight and obese patients, with intensive perioperative management.

Novel risk scoring system for prediction of pancreatic fistula after pancreaticoduodenectomy

BACKGROUND

The available prediction models for clinically relevant postoperative pancreatic fistula (CR-POPF) do not incorporate both preoperative and intraoperative variables.

AIM

To construct a new risk scoring system for CR-POPF that includes both preoperative and intraoperative factors.

METHODS

This was a retrospective study of patients who underwent pancreaticoduodenectomy (PD) or pylorus-preserving PD (PPPD) between January 2011 and December 2016 at the First Affiliated Hospital of Soochow University. Patients were divided into a study (01/2011 to 12/2014) or validation (01/2015 to 12/2016) group according to the time of admission. POPF severity was classified into three grades: Biochemical leak (grade A) and CR-POPF (grades B and C). Logistic regression was used to create a predictive scoring system.

RESULTS

Preoperative serum albumin ≥ 35 g/L [P = 0.032, odds ratio (OR) = 0.92, 95% confidence interval (CI): 0.85-0.99], hard pancreatic texture (P = 0.004, OR = 0.25, 95%CI: 0.10-0.64), pancreatic duct diameter ≥ 3 mm (P = 0.029, OR = 0.50, 95%CI: 0.27-0.93), and intraoperative blood loss ≥ 500 mL (P = 0.006, OR = 1.002, 95%CI: 1.001-1.003) were independently associated with CR-POPF. We established a 10-point risk scoring system to predict CR-POPF. The area under the curve was 0.821 (95%CI: 0.736-0.905) and the cut-off value was 3.5. Including drain amylase levels improved the predictive power of the model.

CONCLUSION

This study established a 10-point scoring system to predict CR-POPF after PD/PPPD using preoperative and intraoperative parameters. Ultimately, this system could be used to distinguish between high- and low-risk populations in order to facilitate timely interventions after PD.

Risk factors of exocrine and endocrine pancreatic insufficiency after pancreatic resection: A multi-center prospective study

Management of functional consequences after pancreatic resection has become a new therapeutic challenge. The goal of our study is to evaluate the risk factors for exocrine (ExoPI) and endocrine (EndoPI) pancreatic insufficiency after pancreatic surgery and to establish a predictive model for their onset.

PATIENTS AND METHODS

Between January 1, 2014 and June 19, 2015, 91 consecutive patients undergoing pancreatoduodenectomy (PD) or left pancreatectomy (LP) (72% and 28%, respectively) were followed prospectively. ExoPI was defined as fecal elastase content<200μg per gram of feces while EndoPI was defined as fasting glucose>126mg/dL or aggravation of preexisting diabetes. The volume of residual pancreas was measured according to the same principles as liver volumetry.

RESULTS

The ExoPI and EndoPI rates at 6 months were 75.9% and 30.8%, respectively. The rate of ExoPI after PD was statistically significantly higher than after LP (98% vs. 21%; P<0.001), while the rate of EndoPI was lower after PD vs. LP, but this difference did not reach statistical significance (28% vs. 38.5%; P=0.412). There was no statistically significant difference in ExoPI found between pancreatico-gastrostomy (PG) and pancreatico-jejunostomy (PJ) (100% vs. 98%; P=1.000). Remnant pancreatic volume less than 39.5% was predictive of ExoPI.

CONCLUSION

ExoPI occurs quasi-systematically after PD irrespective of the reconstruction scheme. The rate of EndoPI did not differ between PD and LP.

The Choice of Palliative Treatment for Biliary and Duodenal Obstruction in Patients With Unresectable Pancreatic Cancer: Is Surgery Bypass Better?

This study aimed to investigate the clinical significance of palliative operation for carcinoma of pancreas between bypass surgery and interventional therapy. Most patients with locally advanced pancreatic cancer cannot undergo resection and show obstructive jaundice at presentation. Methods of palliation in these patients comprise biliary stent or surgical bypass. We retrospectively analyzed the clinical data of 53 patients who underwent palliative treatment with incurable locally advanced pancreatic ductal adenocarcinoma. This retrospective study compared morbidity, mortality, hospital stay, readmission rate, and survival in these patients. A total of 31 patients underwent biliary bypass surgery, and 22 had interventional therapy. There was no significant difference in the patients' basic condition before operation and in the 30-day mortality between surgical palliation and intervention. However, there were some differences in the early complications, survival time, successful biliary drainage, and recurrent jaundice. Through analysis of these clinical data and the published studies, we conclude that surgical bypass is a better effective palliative method for patients than biliary and duodenum stent with locally advanced pancreatic cancer. Patients need to be carefully selected in consideration of operative risk and perceived overall survival.

Connexins and pannexins in the skeleton: gap junctions, hemichannels and more

Regulation of bone homeostasis depends on the concerted actions of bone-forming osteoblasts and bone-resorbing osteoclasts, controlled by osteocytes, cells derived from osteoblasts surrounded by bone matrix. The control of differentiation, viability and function of bone cells relies on the presence of connexins. Connexin43 regulates the expression of genes required for osteoblast and osteoclast differentiation directly or by changing the levels of osteocytic genes, and connexin45 may oppose connexin43 actions in osteoblastic cells. Connexin37 is required for osteoclast differentiation and its deletion results in increased bone mass. Less is known on the role of connexins in cartilage, ligaments and tendons. Connexin43, connexin45, connexin32, connexin46 and connexin29 are expressed in chondrocytes, while connexin43 and connexin32 are expressed in ligaments and tendons. Similarly, although the expression of pannexin1, pannexin2 and pannexin3 has been demonstrated in bone and cartilage cells, their function in these tissues is not fully understood.

Impact of venous thromboembolism on the natural history of pancreatic adenocarcinoma

BACKGROUND

Few studies have analyzed the effect of venous thromboembolism (VTE) events on the prognosis of pancreatic cancer, but their results were conflicting. The present study was undertaken to determine the effect of VTE on pancreatic adenocarcinoma (PA) outcomes.

METHODS

All consecutive patients diagnosed with PA from May 2004 to January 2012 in a single oncology center were retrospectively studied. Clinical, radiological and histological data at time of diagnosis or within the first 3 months after surgery, including the presence (+) or absence (-) of VTE were collected. VTE was defined as radiological evidence of either pulmonary embolism (PE), deep venous thrombosis without infection or catheter-related thrombosis. PA with and without PE was compared for survival using the Kaplan-Meier method to estimate overall survival.

RESULTS

Among 162 PA patients with a median follow-up of 15 (3-92) months after diagnosis, 28 demonstrated VTE (+). PA patients with and without PE were similar for age, American Society of Anesthesiologist score, body mass index, and history of treatment. The distribution of cancer stages was similar between the two groups VTE (+) and VTE (-). The median duration of survival was significantly worse in the VTE (+) group vs VTE (-) (12 vs 18 months, P=0.010). In multivariate analysis, the presence of VTE and surgical treatment were independent prognostic factors for overall survival.

CONCLUSION

VTE (+) at time of diagnosis or within the first 3 months after surgery during treatment is an independent factor of poor prognosis in PA.

Impact of body mass index on complications following pancreatectomy: Ten-year experience at National Cancer Center in China

AIM: To examine the impact of body mass index (BMI) on outcomes following pancreatic resection in the Chinese population.

METHODS: A retrospective cohort study using prospectively collected data was conducted at the Cancer Hospital of the Chinese Academy of Medical Sciences, China National Cancer Center. Individuals who underwent pancreatic resection between January 2004 and December 2013 were identified and included in the study. Persons were classified as having a normal weight if their BMI was < 24 kg/m² and overweight/obese if their BMI was ≥ 24 kg/m² as defined by the International Life Sciences Institute Focal Point in China. A χ² test (for categorical variables) or a t test (for continuous variables) was used to examine the differences in patients’ characteristics between normal weight and overweight/obese groups. Multiple logistic regression models were used to assess the associations of postoperative complications, operative difficulty, length of hospital stay, and cost with BMI, adjusting for age, sex, and type of surgery procedures.

RESULTS: A total of 362 consecutive patients with data available for BMI calculation underwent pancreatic resection for benign or malignant disease from January 1, 2004 to December 31, 2013. Of the 362 patients, 156 were overweight or obese and 206 were of normal weight. One or more postoperative complications occurred in 35.4% of the patients following pancreatic resection. Among patients who were overweight or obese, 42.9% experienced one or more complications, significantly higher than normal weight (29.6%) individuals (P = 0.0086). Compared with individuals who had normal weight, those with a BMI ≥ 24.0 kg/m² had higher delayed gastric emptying (19.9% vs 5.8%, P < 0.0001) and bile leak (7.7% vs 1.9%, P = 0.0068). There were no significant differences seen in pancreatic fistula, gastrointestinal hemorrhage, reoperation, readmission, or other complications. BMI did not show a significant association with intraoperative blood loss, operative time, length of hospital stay, or cost.

CONCLUSION: Higher BMI increases the risk for postoperative complications after pancreatectomy in the Chinese population. The findings require replication in future studies with larger sample sizes.

Pancreatic fistulae after a pancreatico-duodenectomy: are pancreatico-gastrostomies safer than pancreatico-jejunostomies? An expertise-based trial and propensity-score adjusted analysis

BACKGROUND

A pancreatic fistula (PF) is a major contributor to morbidity and mortality after a pancreaticoduodenectomy (PD). There remains debate as to whether re-establishing pancreaticoenteric continuity by a pancreatico-gastrostomy (PG) can decrease the risk of a PF and complications compared with a pancreatico-jejunostomy (PJ). The outcomes of patients undergoing these reconstructions after a PD were compared.

METHOD

Patients undergoing a PD between 1999 and 2011 were selected from a prospective database and having undergone either a PG or PJ reconstruction. A propensity-score adjusted multivariate logistic regression was performed to identify the effect of surgical technique on outcomes of PF, delayed gastric emptying (DGE) and total complications.

RESULTS

Twenty-three out of 103 and 20 out of 103 (P = 0.49) patients had PF and 74 out of 103 and 55 out of 103 patients had all-grades DGE in the PG and PJ groups, respectively (P = 0.02). The groups did not differ with regards to Clavien-Dindo grade of complications (P = 0.29) but did differ with regards to the Comprehensive Complication Index (CCI) (38.4 versus 31.4 for PG versus PG, respectively, P = 0.02.) Propensity-score adjusted multivariate analysis showed no effect of PG on PF (P = 0.89), DGE grades B/C (P = 0.9) or CCI (P = 0.41). There remained an effect on all-grades of DGE (P = 0.012.)

DISCUSSION

Patients undergoing PG reconstruction had a similar rate of PF as those undergoing a PJ after a PD.

Novel diagnostics for aggravating pancreatic fistulas at the acute phase after pancreatectomy

AIM: To identify sensitive predictors of clinically relevant postoperative pancreatic fistula (POPF) at the acute phase after pancreatectomy.

METHODS: This study included 153 patients diagnosed as having POPFs at postoperative day (POD) 3 after either open pancreatoduodenectomy or distal pancreatectomy between January 2008 and March 2013. The POPFs were categorized into three grades based on the International Study Group on Pancreatic Fistula Definition, and POPFs of grades B or C were considered to be clinically relevant. The predictive performance for the clinically relevant POPF formation of values at PODs 1, 3 and 5 as well as time-dependent changes in levels of inflammatory markers, including white blood cell count, neutrophil count, total lymphocyte count, C-reactive protein (CRP), procalcitonin level, platelet-to-lymphocyte ratio and neutrophil-to-lymphocyte ratio, and amylase content in the drain fluid were compared using the receiver operating characteristic (ROC) curve and multivariable analyses. A scoring system for the prediction of clinically relevant POPFs was created using five risk factors identified in this study, and its diagnostic performance was also evaluated.

RESULTS: Over time, 77 (50%) of 153 enrolled patients followed a protracted course and were categorized as having clinically relevant POPFs. ROC curve analyses revealed that changes in CRP levels from POD 1 to POD 3 had the greatest area under the curve value (0.767) and that an elevated CRP level of 28.4 mg/L yielded the most optimal predictive value for clinically relevant POPFs. Multivariable analyses for the risk factors of clinically relevant POPFs identified invasive carcinomas of the pancreas and elevation of the CRP level (≥ 28.4 mg/L, from POD 1 to POD 3) as independent diagnostic factors for clinically relevant POPFs (OR 2.94, 95%CI: 1.08-8.55, P = 0.035 and OR 4.82, 95%CI: 1.25-20.2, P = 0.022, respectively). A gradual increase in the prevalence of clinically relevant POPFs in proportion to the risk classification score was confirmed. A highly elevated CRP level and a risk score ≥ 8 were significantly associated with a prolonged duration of drain placement and postoperative hospitalization.

CONCLUSION: A steep rise in the serum CRP level from POD 1 to POD 3 was a highly predictive factor for subsequent clinically relevant POPFs.

Vascular resection during radical resection of pancreatic adenocarcinomas: evolution over the past 15 years

This literature review aimed to critically analyze oncological results of vascular resection during pancreatectomy for adenocarcinoma in the light of the concept evolution of locally advanced tumors and microscopic complete resection. The literature search was conducted in PubMed and Medline for the period June 1994 to December 2012, retaining English as the language of publication. The review of 12 publications indicated that mortality and morbidity rates were not significantly different for pancreatectomy with or without venous resection (VR). Six comparative studies showed worse long-term survival in the VR group, though one meta-analysis, albeit with a significant population heterogeneity, demonstrated that the overall survival between VR and the control group was similar (12% vs. 17%). The compilation of 13 comparative studies showed a significantly lower rate of complete microscopic resection in the VR patient group compared to controls (63% vs. 77%; P = 0.001). Concerning pancreatectomy combined to arterial resection, the literature review indicated a significantly greater mortality and morbidity rate and a lower survival rate compared to pancreatic resection alone. Conflicting results concerning the long-term outcome of VR was due to the heterogeneity of the patient population. Since the only chance to cure patients of pancreatic adenocarcinoma is to obtain free resection margins, VR is a valid therapeutic option. But combined arterial resection to pancreatic resection does not appear to be recommended.

Comparative analysis of the efficacy and complications of nasojejunal and jejunostomy on patients undergoing pancreaticoduodenectomy

BACKGROUND

The efficacy and feeding-related complications of a nasojejunal feeding tube and jejunostomy after pancreaticoduodenectomy (PD) was investigated with a randomized, controlled clinical trial at the Affiliated Drum Tower Hospital.

METHODS

Sixty-eight patients who underwent PD in the Department of Hepatobiliary Surgery were randomly divided into 2 groups: 34 patients received enteral feeding via a nasojejunal tube (NJT group) and 34 patients received enteral feeding via a jejunostomy tube (JT group). The assessment of clinical outcome was based on postoperative investigation of complications. The second part of the assessment included tube related complications and an index on catheter efficiency.

RESULTS

There were 15 cases with infectious complications in the JT group and 13 cases in the NJT group, and there was no significant difference in the rate of infectious complications between the 2 groups. The rate of intestinal obstruction and delayed gastric emptying was significantly decreased in the NJT group (P < .05). Catheter-related complications were more common in the JT group as compared with the NJT group (35.3% vs 20.6%, P < .05). The time for removal of the feeding tube and nasogastric tube was significantly decreased in the NJT group. The postoperative hospital stay in the NJT group was significantly decreased (P < .05), and there was no hospital mortality in this study.

CONCLUSION

Nasojejunal feeding is safer than jejunostomy, and it is associated with only minor complications. Nasojejunal feeding can significantly decrease the incidence of delayed gastric emptying and shorten the postoperative hospital stay.