Smooth muscle distribution in the extrahepatic bile duct: histologic and immunohistochemical studies of 122 cases

Long-term prognosis and risk factors associated with post-ERCP pneumobilia in patients with common bile duct stones

BACKGROUND AND AIMS

Post-ERCP pneumobilia is not uncommon; however, studies focusing on the long-term prognosis of patients with post-ERCP pneumobilia are limited. This study aimed to explore long-term prognosis and risk factors associated with post-ERCP pneumobilia in patients with common bile duct stones (CBDSs).

METHODS

We conducted a retrospective analysis of 1380 patients who underwent ERCP for CBDSs at our hospital from January 2010 to December 2017. Patients were selected based on inclusion and exclusion criteria and divided into pneumobilia and nonpneumobilia groups, followed by propensity score matching. The matched groups were then compared in terms of incidence rates of both single and multiple recurrences of CBDSs, acute cholangitis, and acute cholecystitis. Multivariate logistic regression analysis was used to explore risk factors associated with pneumobilia.

RESULTS

After propensity matching, there was no significant difference in the rate of single recurrence of CBDSs (22.5% vs 30%; P = .446) between the pneumobilia and nonpneumobilia groups. However, the incidences of multiple recurrences of CBDSs (32.5% vs 12.5%; P = .032) and acute cholangitis without stone recurrence (32.5% vs 2.5%; P = <.001) were significantly higher in the pneumobilia group. Based on multivariate logistic regression analysis, in addition to a dilated CBD (diameter of >1 cm) (odds ratio [OR], 2.48; 95% confidence interval [CI], 1.03-3.76; P = .043), endoscopic sphincterotomy with moderate incision (OR, 5.38; 95% CI, 1.14-25.47; P = .034) and with large incision (OR, 8.7; 95% CI, 1.83-41.46; P = .007) were identified as independent risk factors for pneumobilia after initial ERCP.

CONCLUSIONS

Patients with post-ERCP pneumobilia have increased risk of multiple recurrences of CBDSs and acute cholangitis without stone recurrence. Independent risk factors for pneumobilia include peripapillary diverticulum, a dilated CBD (>1 cm), and endoscopic sphincterotomy with moderate and large incisions. A normal-sized CBD appears to serve as a secondary barrier against enterobiliary reflux, necessitating further research for confirmation.

Subserosal Layer and/or Pancreatic Invasion Based on Anatomical Features as a Novel Prognostic Indicator in Patients with Distal Cholangiocarcinoma

The American Joint Committee on Cancer (AJCC) 8th edition T-staging system for distal cholangiocarcinoma (DCC) proposes classification according to the depth of invasion (DOI); nevertheless, DOI measurement is complex and irreproducible. This study focused on the fibromuscular layer and evaluated whether the presence or absence of penetrating fibromuscular invasion of DCC contributes to recurrence and prognosis. In total, 55 patients pathologically diagnosed with DCC who underwent surgical resection from 2002 to 2022 were clinicopathologically examined. Subserosal layer and/or pancreatic (SS/Panc) invasion, defined as penetration of the fibromuscular layer and invasion of the subserosal layer or pancreas by the cancer, was assessed with other clinicopathological prognostic factors to investigate recurrence and prognostic factors. According to the AJCC 8th edition, there were 11 T1, 28 T2, and 16 T3 cases, with 44 (80%) cases of SS/Panc invasion. The DOI was not significantly different for both recurrence and prognostic factors. In the multivariate analysis, only SS/Panc was identified as an independent factor for prognosis (hazard ratio: 16.1; 95% confidence interval: 2.1-118.8, p = 0.006). In conclusion, while the determination of DOI in DCC does not accurately reflect recurrence and prognosis, the presence of SS/Panc invasion may contribute to the T-staging system.

In vivo detection of bile duct pre-cancer with endoscopic light scattering spectroscopy

Bile duct cancer is the second most common primary liver cancer, with most diagnoses occurring in the advanced stages. This leads to a poor survival rate, which means a technique capable of reliably detecting pre-cancer in the bile duct is urgently required. Unfortunately, radiological imaging lacks adequate accuracy for distinguishing dysplastic and benign biliary ducts, while endoscopic techniques, which can directly assess the bile duct lining, often suffer from insufficient sampling. Here, we report an endoscopic optical light scattering technique for clinical evaluation of the malignant potential of the bile duct. This technique employs an ultraminiature spatial gating fiber optic probe compatible with cholangioscopes and endoscopic retrograde cholangiopancreatography (ERCP) catheters. The probe allowed us to investigate the internal cellular composition of the bile duct epithelium with light scattering spectroscopy (LSS) and phenotypic properties of the underlying connective tissue with diffuse reflectance spectroscopy (DRS). In a pilot in vivo double-blind prospective study involving 29 patients undergoing routine ERCP procedures, the technique detected malignant transformation with 97% accuracy, showing that biliary duct pre-cancer can be reliably identified in vivo non-invasively.

Radiologic Evaluation and Structured Reporting Form for Extrahepatic Bile Duct Cancer: 2019 Consensus Recommendations from the Korean Society of Abdominal Radiology

Radiologic imaging is important for evaluating extrahepatic bile duct (EHD) cancers; it is used for staging tumors and evaluating the suitability of surgical resection, as surgery may be contraindicated in some cases regardless of tumor stage. However, the published general recommendations for EHD cancer and recommendations guided by the perspectives of radiologists are limited. The Korean Society of Abdominal Radiology (KSAR) study group for EHD cancer developed key questions and corresponding recommendations for the radiologic evaluation of EHD cancer and organized them into 4 sections: nomenclature and definition, imaging technique, cancer evaluation, and tumor response. A structured reporting form was also developed to allow the progressive accumulation of standardized data, which will facilitate multicenter studies and contribute more evidence for the development of recommendations.

Prognostic effects of histology-based tumour microenvironment scores in resected distal bile duct cancer

AIMS

Histology-based tumour microenvironment (TME) scores are useful in predicting the prognosis of gastrointestinal cancer. However, their prognostic roles in distal bile duct cancer (DBDC) have not been previously studied. This study aimed to evaluate the prognostic significance of the TME scores using the Klintrup-Mäkinen (KM) grade, tumour stroma percentage (TSP) and the Glasgow microenvironment score (GMS) in resected DBDC.

METHODS AND RESULTS

Eighty-one patients with DBDC who underwent curative resection were enrolled. DBDC was graded according to KM grade, TSP and GMS. A high KM grade was found in 19 patients (24%) and a high TSP was found in 47 patients (58%). A high TSP was significantly correlated with a low KM grade (P < 0.001). The distribution of the GMS, which was developed by combining the KM grade and TSP, was as follows: 0 (n = 19, 24%), 1 (n = 19, 24%) and 2 (n = 43, 52%). A low KM grade, high TSP and high GMS were significantly associated with short overall survival (OS) (P < 0.001) and relapse-free survival (RFS) (P < 0.001). Furthermore, multivariate analysis showed that a low KM grade [hazard ratio (HR) = 3.826; confidence interval (CI) = 1.650-8.869; P = 0.014], high TSP (HR = 2.193; CI = 1.173-4.100, P = 0.002) and high GMS (HR = 7.148; CI = 2.811-18.173) were independent prognostic factors for short RFS; a low KM grade (HR = 4.324; CI = 1.594-11.733) and high GMS (HR = 6.332; CI = 2.743-14.594) were independent prognostic factors for short OS.

CONCLUSION

Histology-based TME scores, including the KM grade, TSP and GMS, are useful for predicting the survival of patients with resected DBDC.

Smooth Muscle Distribution Patterns of Choledochal Cysts and Their Implications for Pathogenesis and Postoperative Complications

OBJECTIVES

Histopathologic characteristics of choledochal cysts and their clinical implications have not been previously comprehensively studied.

METHODS

Smooth muscle distribution patterns and other histologic findings (inflammation, metaplasia, dysplasia, and heterotopia) in 233 surgically resected choledochal cysts were evaluated.

RESULTS

Mean patient age was 23.3 ± 19.8 years, with male:female ratio of 0.3. Most cases were Todani type I (175 cases, 75.1%) or IVa (56 cases, 24.1%). Choledochal cysts with thin scattered/no muscle fiber (175 cases, 75.1%) were the predominant pattern and were associated with more frequent postoperative biliary stricture (P = .031), less frequent pyloric metaplasia (P = .016), and mucosal smooth muscle aggregates (P < .001) compared to cysts with thick muscle bundles. Severe chronic cholangitis (P = .049), pyloric metaplasia (P = .019), mucosal smooth muscle aggregates (P < .001), biliary intraepithelial neoplasia (P = .021), and associated bile duct (P = .021) and gallbladder carcinomas (P = .03) were more common in adults (age >20 years vs ≤20 years), suggesting that chronic irritation in association with developmental anomalies involves tumorigenesis from choledochal cysts.

CONCLUSION

Smooth muscle distribution pattern of choledochal cyst may predict postoperative complication, raising clinical implications of smooth muscle patterns in postoperative management of choledochal cysts.

Prognostic Predictability of American Joint Committee on Cancer 8th Staging System for Perihilar Cholangiocarcinoma: Limited Improvement Compared with the 7th Staging System

Purpose

This study was conducted to evaluate the prognostic values of the 7th and 8th American Joint Committee on Cancer (AJCC) staging systems for patients with resected perihilar cholangiocarcinoma (PHCC).

Materials and Methods

A total of 348 patients who underwent major hepatectomy for PHCC between 2008 and 2015 were identified from a single center. Overall survival (OS) was estimated using the Kaplan-Meier method and compared across stage groups with the log-rank test. The concordance index was used to evaluate the prognostic predictability of the 8th AJCC staging system compared with that of the 7th.

Results

In the 8th edition, the stratification of each group of T classification improved compared to that in the 7th, as the survival rate of T4 decreased (T2, 31.2%; T3, 13.9%; T4, 15.1%; T1-T2, p=0.260; T2-T3, p=0.001; T3-T4, p=0.996). Both editions showed significant survival differences between each N category, except between N1 and N2 (p=0.063) in 7th edition. Differences of point estimates between the 8th and 7th T and N classification and overall stages were +0.028, +0.006, and +0.039, respectively (T, p=0.005; N, p=0.115; overall stage, p=0.005). In multivariable analysis, posthepatectomy liver failure, T category, N category, distant metastasis, histologic differentiation, intraoperative transfusion, and resection margin status were associated with OS.

Conclusion

The prognostic predictability of 8th AJCC staging for PHCC improved slightly, with statistical significance, compared to the 7th edition, but its overall performance is still unsatisfactory.

Biomechanical behaviour of human bile duct wall and impact of cadaveric preservation processes

Biliary diseases are the third most common cause of surgical digestive disease. There is a close relationship between the mechanical performance of the bile duct and its physiological function. Data of biomechanical properties of human main bile duct are scarce in literature. Furthermore, mechanical properties of soft tissues are affected by these preservation procedures. The aim of the present work was, on the one hand, to observe the microstructure of the human bile duct by means of histological analysis, on the other hand, to characterize the mechanical behavior and describe the impact of different preservation processes. A mechanical study in a controlled environment consisting of cyclic tests was made. The results of the mechanical tests are discussed and explained using the micro-structural observations. The results show an influence of the loading direction, which is representative of an anisotropic behavior. A strong hysteresis due to the viscoelastic properties of soft tissues was also observed. Embalming and freezing preservation methods had an impact on the biomechanical properties of human main bile duct, with fiber network deterioration. That may further provide a useful quantitative baseline for anatomical and surgical training using embalming and freezing.

A systematic review of the anatomical findings of multiple gallbladders

BACKGROUND

Multiple gallbladders (MG) are a rare malformation, with no clear data on its clinical impact, therapeutic indications or risk for malignancy.

METHODS

A systematic review of all published literature between 1990 and 2017 was performed using the PRISMA guidelines.

RESULTS

Data of 181 patients extracted from 153 studies were reviewed. MG were diagnosed during the treatment of a gallstone-related disease in 83% of patients, of which 13% had previous cholecystectomy and had a recurrence of biliary stone disease. The sensitivity of ultrasound scan was 66%, and that of magnetic resonance imaging cholangio-pancreatography, 97%. The cystic duct was common to both gallbladders (type1) in 43% and separated (type 2) in 50% of patients. In the latter case, there was no way to differentiate preoperatively an accessory gallbladder from a Todani II bile duct cyst. Cholecystectomy was performed in 129 patients by laparotomy (43%) or laparoscopy (56%). MG was undiagnosed before surgery in 24% of the patients. The postoperative biliary leakage rate was 0.7%. In two patients, gallbladder cancers were detected.

CONCLUSION

MG are difficult to diagnose and share a common natural history with single gallbladders, without evidence of increased risk for malignancy. Excision of both gallbladders is indicated in symptomatic stone disease. However, prophylactic cholecystectomy must be considered for type 2 MG, since it cannot be preoperatively differentiated from a Todani II bile duct cyst, which is associated with a risk of malignant transformation.

Reappraisal of classification of distal cholangiocarcinoma based on tumour depth

Background

In the eighth edition of the AJCC cancer staging classification, the T system for distal cholangiocarcinoma (DCC) has been revised from a layer-based to a depth-based approach. The aim of this study was to propose an optimal T classification using a measured depth in resectable DCC.

Methods

Patients who underwent pancreatoduodenectomy for DCC at 32 hospitals between 2001 and 2010 were included. The distance between the level of the naive bile duct and the deepest cancer cells was measured as depth of invasion (DOI). Invasive cancer foci were measured as invasive tumour thickness (ITT). Log rank χ2 scores were used to determine the cut-off points, and concordance index (C-index) to assess the survival discrimination of each T system.

Results

Among 404 patients, DOI was measurable in 182 (45·0 per cent) and ITT was measurable in all patients, with median values of 2·3 and 5·6 mm respectively. ITT showed a positive correlation with DOI (rs = 0·854, P &lt; 0·001), and the cut-off points for prognosis were 1, 5 and 10 mm. Median survival time was shorter with increased ITT: 12·4 years for ITT below 1 mm, 5·2 years for ITT at least 1 mm but less than 5 mm, 3·0 years for ITT at least 5 mm but less than 10 mm, and 1·5 years for ITT 10 mm or more (P &lt; 0·001). This classification exhibited more favourable prognostic discrimination than the T systems of the seventh and eighth editions of the AJCC (C-index 0·646, 0·622 and 0·624 respectively).

Conclusion

ITT is an accurate approach for depth assessment in DCC. The four-tier ITT classification with cut-off points of 1, 5 and 10 mm seems to be a better T system than those in the seventh and eighth editions of the AJCC classification.

Prognostic predictability of the new American Joint Committee on Cancer 8th staging system for distal bile duct cancer: limited usefulness compared with the 7th staging system

BACKGROUND

The new 8th American Joint Committee on Cancer (AJCC) staging has recently been released and there are major changes in distal bile duct (DBD) cancer staging. However, clinical validation is needed before the changes can be widely implemented.

METHODS

This study was performed to evaluate the prognostic predictability of the 8th AJCC staging compared with that of the 7th using C statistics.

RESULTS

A total of 293 consecutive patients who had curative-intended surgery were enrolled. There was no significant difference of the 5-year survival rate between 7th T1 and T2 (P = 0.123), but significant difference between T2 and T3 (P = 0.039). There were significant differences in pairwise comparisons between the 8th T stage (T1 vs. T2, P = 0.001; T2 vs. T3, P = 0.014). The number of regional lymph node metastases also showed prognostic predictability. The 8th T and N stage both showed comparable prognostic predictability with the 7th (95% confidential intervals for C; T, -0.043 -0.097, N, -0.001 - 0.008).

CONCLUSIONS

The 8th AJCC staging for DBD cancer does not have better prognostic predictability than the 7th stage does. The previous pathologic results would become useless unless they were reviewed entirely. Therefore, introduction of the AJCC 8th staging has to be reconsidered, especially for new T staging.

Validation of Feasibility of Magnetic Resonance Imaging for the Measurement of Depth of Tumor Invasion in Distal Bile Duct Cancer According to the New American Joint Committee on Cancer Staging System

RATIONALE AND OBJECTIVES

This study aimed to develop and validate a method for measuring the depth of tumor invasion (DoI) using magnetic resonance imaging (MRI) and to investigate the diagnostic performance of the measured DoI for stratifying tumor (T) classification in patients with distal bile duct cancer according to the new American Joint Committee on Cancer staging system.

MATERIALS AND METHODS

Fifty-four patients (30 men and 24 women; age range, 43-81 years) with distal bile duct cancer were enrolled. A study coordinator first developed a "provisional method" for measuring DoI on T2-weighted MRI. Subsequently, after compensating for defects, the "improved method" was developed. Two reviewers independently measured DoI and assessed its correlations with the histopathologic reference standard using intraclass correlation coefficient (ICC). The study population was grouped according to the DoI for T classification based on the new staging system for evaluation of diagnostic predictive values.

RESULTS

The ICC values between the radiologic and the histopathologic DoI were calculated. Using the "improved method," the ICC for the coordinator's DoI was very good (ICC, 0.885), which was a significantly higher value than that obtained using the "provisional method" (ICC, 0.501, P = .00000); and for two reviewers' DoIs, the ICC values were good (ICC, 0.752 and 0.784, respectively). The overall accuracy of MRI for stratifying bile duct tumors using DoI was 87.0% and 85.2%, respectively.

CONCLUSIONS

This newly developed method reliably measured DoI on T2-weighted MRI and can be used for preoperative T classification of patients with distal bile duct cancer according to the new staging system.

Advances in the generation of bioengineered bile ducts

The generation of bioengineered biliary tissue could contribute to the management of some of the most impactful cholangiopathies associated with liver transplantation, such as biliary atresia or ischemic cholangiopathy. Recent advances in tissue engineering and in vitro cholangiocyte culture have made the achievement of this goal possible. Here we provide an overview of these developments and review the progress towards the generation and transplantation of bioengineered bile ducts. This article is part of a Special Issue entitled: Cholangiocytes in Health and Diseaseedited by Jesus Banales, Marco Marzioni and Peter Jansen.

Initial large diameter of common bile duct is associated with long-term dilatation of bile duct after endoscopic extraction of stones

OBJECTIVE

To investigate the time and extent of recovery of dilated common bile duct (CBD) after the extraction of CBD stones and to identify the factors related to the long-term dilatation of the CBD after stone removal.

METHODS

Data of 329 consecutive patients undergoing endoscopic extraction of CBD stones from January 2008 to December 2012 were retrospectively reviewed. Finally, 44 patients were enrolled in the study.

RESULTS

The CBD diameter significantly decreased after stone extraction (P < 0.001). However, the CBD diameter in patients who were followed up for 1 week and longer and <1 week did not differ significantly. The diameter decreased more in patients with an initial CBD diameter ≥ 15 mm than in those with an initial CBD diameter <15 mm before stone extraction (P = 0.007), but the normalization of dilated CBD was less frequent in patients with a large initial CBD diameter. The factors related to the long-term dilatation of CBD (>10 mm for >6 months) were initial CBD diameter, the largest diameter of CBD stone and endoscopic papillary large balloon dilatation. Initial CBD diameter was an independent factor with multivariate analysis (OR 1.754, P = 0.017).

CONCLUSIONS

The CBD diameter recovers rapidly after the extraction of CBD stones. An initial large CBD diameter before stone extraction is associated with the long-term dilatation of CBD.

Hilar cholangiocarcinoma: tumor depth as a predictor of outcome

BACKGROUND

The American Joint Committee on Cancer staging system for hilar cholangiocarcinoma may be inaccurate because the bile duct lacks discrete tissue boundaries.

OBJECTIVES

To examine the accuracy of the American Joint Committee on Cancer staging schemes and to determine the prognostic implications of tumor depth.

DESIGN, SETTING, AND PATIENTS

From January 1, 1987, through December 31, 2009, there were 106 patients who underwent resection of hilar cholangiocarcinoma who had pathologic slides available for re-review.

MAIN OUTCOME MEASURES

Tumor depth and overall survival.

RESULTS

Overall median survival was 19.9 months. The 6th and 7th editions of the T-classification criteria were unable to discriminate among T1, T2, and T3 lesions (P > .05 for all). Median survival was associated with the invasion depth of the tumor (≥5 mm vs <5 mm): 18 months vs 30 months (P = .01). On multivariate analysis, tumor depth remained predictive of disease-specific death (hazard ratio, 1.70; P = .03).

CONCLUSIONS

The American Joint Committee on Cancer T-classification criteria did not stratify patients with regard to prognosis. Depth of tumor invasion is a better predictor of long-term outcome.

Staging of extrahepatic cholangiocarcinoma

Preoperative staging of extrahepatic cholangiocarcinoma is important in determining the best treatment plan. Several classification systems have been suggested to determine the operability and extent of surgery. Longitudinal tumor extent is especially important in extrahepatic cholangiocarcinoma because operative methods differ depending on the tumor extent. The Bismuth-Corlette classification system provides useful information when planning for surgery. However, this classification system is not adequate for selecting surgical candidates. Anatomic variation of the bile duct and gross morphology of the tumor must be considered simultaneously. Lateral spread of the tumor can be evaluated based on the TNM staging provided by American Joint Committee on Cancer (AJCC). However, there is a potential for ambiguity in the distinction of T1 and T2 cancer from one another. In addition, T stage does not necessarily mean invasiveness. Blumgart T staging is helpful for the assessment of resectability with the consideration of nodal status and distant metastasis as suggested by the AJCC cancer staging system. Computed tomography (CT) and magnetic resonance imaging (MRI) are the primary tools used in the assessment of longitudinal and lateral spread of a tumor when determining respectability. Diagnostic laparoscopy and positron emission tomography (PET) may play additional roles in this regard.

Early bile duct cancer

Bile duct cancers are frequently diagnosed as advanced diseases. Over half of patients with advanced bile duct cancer present with unresectable malignancies and their prognosis has been very poor even after curative resections. Although there has been a need to diagnose bile duct cancer at its early stage, it has been a difficult goal to achieve due to our lack of knowledge regarding this disease entity. Early bile duct cancer may be defined as a carcinoma whose invasion is confined within the fibromuscular layer of the extrahepatic bile duct or intrahepatic large bile duct without distant metastasis irrespective of lymph node involvement. Approximately 3%-10% of resected bile duct cancers have been reported to be early cancers in the literature. The clinicopathological features of patients with early bile duct cancer differ from those of patients with advanced bile duct cancer, with more frequent asymptomatic presentation, characteristic histopathological findings, and excellent prognosis. This manuscript is organized to emphasize the need for convening an international consensus to develop the concept of early bile duct cancer.

Clinical and prognostic significances of nuclear and cytoplasmic KIT expressions in extrahepatic bile duct carcinomas

After receiving FDA approval as a therapeutic regimen in gastrointestinal stromal tumors, the tyrosine kinase inhibitor imatinib mesylate has been applied to the treatment of other solid malignant neoplasms. To evaluate the usefulness of imatinib mesylate as a possible therapeutic regimen in extrahepatic bile duct carcinomas, an immunohistochemical study for KIT was performed in 289 cases of extrahepatic bile duct carcinomas, and mutational analysis of exon 11 of the c-kit gene was performed in 20 cases that were arbitrarily retrieved from the cases with KIT expression. Cytoplasmic KIT expression was observed in 54 cases (19%) and nuclear KIT in 58 cases (20%) of extrahepatic bile duct carcinoma. Nuclear KIT expression was more frequent in cases with vascular invasion (P<0.001), whereas cytoplasmic KIT expression was more common in tumors of T1-T3 than in those of T4 (P=0.04), and was more frequently observed in cases with a papillary growth pattern (P=0.03). Patients with cytoplasmic KIT-positive tumors had significantly better survival both by univariate (P=0.01) and multivariate analyses (P=0.04). Infrequent cytoplasmic KIT expression without mutation of exon 11 suggests that imatinib mesylate may not be effective for the treatment of extrahepatic bile duct carcinoma. However, immunohistochemical study for KIT may be helpful in routine pathologic examinations for evaluating better prognosis for patients with extrahepatic bile duct carcinoma. In addition, more frequent nuclear expression of KIT in cases with vascular invasion suggests that nuclear KIT expression may contribute to the progression of extrahepatic bile duct carcinoma.

Measurement of the invasion depth of extrahepatic bile duct carcinoma: An alternative method overcoming the current T classification problems of the AJCC staging system

Tumor staging of extrahepatic bile duct (EBD) carcinoma is problematic for a number of reasons, including definitional problems with the current T classification of the American Joint Committee on Cancer staging system and the common occurrence of severe desmoplastic stromal reaction around the advancing edges of these tumors. To address these problems we evaluated the depth of invasion in 222 cases of EBD carcinoma by measuring the distance between the basal lamina of the adjacent normal epithelium to the most deeply infiltrating tumor cells, and compared this evaluation to time of survival and other clinical and pathologic parameters. A complex pattern of survival time versus the depth of invasion was observed by censored local regression. The recursive-partitioning technique was coupled with the log-rank test to identify 2 significant cutoff points for the depth of invasion, 5 and 12 mm, which segregated patients into 3 groups with statistically significant decreasing length of median survival (<5 mm, 61 mo; 5 to 12 mm, 23 mo; >12 mm, 17 mo, P < 0.001). On the basis of the present data, we propose that a measurement of the depth of invasion should be performed in cases of EBD carcinoma, and that the T classification of EBD carcinoma should be changed to incorporate this measurement: T1 (<5 mm), T2 (5 to 12 mm), and T3 (>12 mm).

Reconsideration of the histologic definitions used in the pathologic staging of extrahepatic bile duct carcinoma

The histologic boundaries of the extrahepatic bile ducts (EBDs) are not well defined, despite the fact that pathologic staging of carcinomas arising in these structures requires the determination of extent of tumor invasion in this area. Perhaps in part, because the smooth muscle band in the EBD wall is not well formed throughout the length of these structures, a previous definition of the outer portion of the bile duct wall included "loose, richly vascularized connective tissue, interlaced with large nerve fibers." We have experienced difficulty in the application of these criteria in staging EBD carcinomas, which requires the histologic determination of the extent of the EBD wall. To systematically study the histologic features of EBD tissue boundaries, 34 EBD specimens obtained from autopsy were analyzed with attention to the distribution of blood vessels and nerve fibers along the length of this system. The EBD specimens were divided into lower, middle, and upper portions, and the locations of blood vessels and nerve fibers were then analyzed separately at each location. We defined the fibromuscular wall as the dense concentric arrangement of collagen and smooth muscle fibers surrounding the EBD mucosa. The location of blood vessels and nerve fibers was categorized as either (1) within, (2) junctional to, or (3) outside of the fibromuscular wall. Blood vessels and nerve fibers are located predominantly outside of the fibromuscular wall and are usually surrounded by adipose tissue throughout the entire EBD, however, their distribution in this location is not consistent. Because of these histologic features, we propose that the bile duct wall is more precisely defined as occurring between the mucosa and the outermost boundary of dense fibromuscular tissue, without consideration of the presence or absence of blood vessels and nerve fibers.

Analysis of extrahepatic bile duct carcinomas according to the New American Joint Committee on Cancer staging system focused on tumor classification problems in 222 patients

BACKGROUND

Although the sixth edition of the American Joint Committee on Cancer (AJCC) staging system for extrahepatic bile duct carcinoma was updated, the system has a problem on T classification due to its ambiguous definition of T1 as "tumor confined to bile duct histologically" and T2 as "tumor invading beyond the bile duct."

METHODS

The authors considered the outermost part of the muscle layer or fibrous tissue as within the extrahepatic bile duct and considered the area starting from large clusters of adipose tissue as beyond the extrahepatic bile duct. After designing a precise definition of the extrahepatic bile duct wall, they analyzed the new AJCC staging system in 222 patients with of extrahepatic bile duct carcinomas. Then, other clinicopathologic variables for prognosis were evaluated using univariate and multivariate analyses.

RESULTS

The 5-year survival rates for patients with tumors that were classified as T1, T2, T3, and T4 were 53.1%, 29.7%, 24.9%, and 0%, respectively. There was a significant difference in survival between patients with T1 tumors and T2 tumors (P < 0.05), but not between patients with T2 tumors and T3 tumors. Significant prognostic factors included depth of invasion (P < 0.005), lymph node metastasis (P < 0.005), and patient age (P < 0.05).

CONCLUSIONS

Based on a proposed histologic definition, depth of invasion was practical for evaluating the prognosis of patients with middle and upper extrahepatic bile duct carcinomas. Therefore, the authors recommended changing the current pT1 and pT2 classifications to more precise pathologic terminology.

Influence of indomethacin on effects of endothelin-1 on guinea pig isolated rings of common bile duct and sphincter of Oddi

The effects of endothelin-1 on motility of guinea pig extra-hepatic biliary tract portions were studied. Endothelin-1 (< or =100 nM) failed to contract rings of hepatic, cystic, proximal or distal common bile ducts, or choledochal or papillary halves of sphincter of Oddi. At 100 nM, endothelin-1 or sarafotoxin S6c (selective endothelin ET(B) receptor agonist) inhibited contractions of choledochal (but not papillary) sphincter of Oddi to carbachol (1 microM) by 63+/-5 and 45+/-9%, respectively. In distal common bile duct, indomethacin (5.6 microM) unmasked potent contractile effects of endothelin-1 [EC(50) 7.8 (5.5-11.1) nM; E(MAX) 80+/-6% of response to 80 mM KCl] and enhanced the contractile potency of carbachol (585-fold at EC(50) level), but not cholecystokinin C-terminal octapeptide. Inhibition of cholinergic responsiveness of the choledochal sphincter of Oddi by endothelin-1 was reduced by BQ-123 (1 microM; endothelin ET(A) receptor antagonist; cyclo[DTrp-DAsp-Pro-DVal-Leu]) and abolished by either BQ-123 plus BQ-788 (1 microM; endothelin ET(B) receptor antagonist; N-cis-2,6-dimethylpiperidinocarbonyl-L-gamma-methylleucyl-D-1-methoxycarboyl-D-norleucine) or indomethacin. Thus, eicosanoids of the cyclo-oxygenase pathway (i.e. prostanoids) suppress endothelin-1-induced contractions of distal common bile duct and mediate endothelin ET(A) and ET(B) receptor-dependent inhibition of cholinergic responsiveness of the choledochal portion of the sphincter of Oddi.