Validation of T Stage According to Depth of Invasion and N Stage Subclassification Based on Number of Metastatic Lymph Nodes for Distal Extrahepatic Bile Duct (EBD) Carcinoma

Clinical impact of pancreatic invasion in T1-stage distal bile duct cancer and prognostic factors associated with long-term survival: A multicenter study

BACKGROUND/PURPOSE

The eighth edition of the AJCC staging system introduced a shift in the staging of distal bile duct cancer (DBC), emphasizing the depth of invasion over adjacent organ invasion. This study aimed to evaluate the clinical impact of pancreatic invasion in pT1-stage DBC and identify prognostic factors for long-term survival.

METHODS

This multicenter retrospective analysis encompassed DBC patients who underwent pancreaticoduodenectomy between 2009 and 2019 in six Korean tertiary centers, specifically those with final pathology confirming AJCC eighth edition T1 stage and intrapancreatic bile duct tumor origin. Primary endpoints were five-year recurrence-free survival (RFS) and overall survival (OS). Secondary objectives included the identification of prognostic determinants.

RESULTS

This study involved 287 patients, comprising 190 without and 97 with pancreatic invasion. Pancreatic invasion did not significantly influence five-year OS and RFS rates (OS: without pancreatic invasion 69.9% vs. with pancreatic invasion 54.1%, p = .25; RFS: 56.3% vs. 55.4%, p = .97). Multivariate analysis highlighted male gender, age, lymphovascular invasion, and N stage as significant OS determinants. Notably, male gender, ampulla of Vater invasion, lymphovascular invasion, and N1 stage were also associated with RFS.

CONCLUSIONS

In pT1 DBC, pancreatic invasion demonstrates no substantial impact on long-term prognosis, in accordance with the depth-based paradigm of the eighth edition AJCC staging system. The prognostic factors influencing OS were identified as male gender, age, lymphovascular invasion, and nodal metastasis.

Retrospective analysis of 8th edition American Joint Cancer Classification: Distal cholangiocarcinoma

Backgrounds/Aims

This is a retrospective analysis of whether the 8th edition American Joint Committee on Cancer (AJCC) was a significant improvement over the 7th AJCC distal extrahepatic cholangiocarcinoma classification.

Methods

In total, 111 patients who underwent curative resection of mid-distal bile duct cancer from 2002 to 2019 were included. Cases were re-classified into 7th and 8th AJCC as well as clinicopathological univariate and multivariate, and Kaplan-Meier survival curve and log rank were calculated using R software.

Results

In patient characteristics, pancreaticoduodenectomy/pylorus preserving pancreaticoduodenectomy had better survival than segmental resection. Only lymphovascular invasion was found to be significant (hazard ratio 2.01, p = 0.039) among all clinicopathological variables. The 8th edition AJCC Kaplan Meier survival curve showed an inability to properly segregate stage I and IIA, while there was a large difference in survival probability between IIA and IIB.

Conclusions

The 8th distal AJCC classification did resolve the anatomical issue with the T stage, as T1 and T3 showed improvement over the 7th AJCC, and the N stage division of the N1 and N2 category was found to be justified, with poorer survival in N2 than N1. Meanwhile, in TMN staging, the 8th AJCC was able differentiate between early stage (I and IIA) and late stage (IIB and III) to better explain the patient prognosis.

Prognostic Factors for Distal Bile Duct Carcinoma After Surgery

BACKGROUND

Distal bile duct carcinoma continues to be one of the most difficult cancers to manage in terms of staging and radical resection. Pancreaticoduodenectomy (PD) with regional lymph node dissection has become the standard treatment of distal bile duct carcinoma. We evaluated treatment outcomes and histological factors in patients with distal bile duct carcinoma.

METHODS

Seventy-four cases of resection of carcinoma of the distal bile ducts treated at our department during the period from January 2002 and December 2016 using PD and regional lymph node dissection as the standard surgical procedure were investigated. Survival rates of factors were analyzed using uni- and multivariate analyses.

RESULTS

The median survival time was 47.8 months. On univariate analysis, age of 70 years or older, histologically pap, pPanc2,3, pN1, pEM0, v2,3, ly2,3, ne2,3 and postoperative adjuvant chemotherapy were statistically significant factors. On multivariate analysis, histologically pap was identified as a significant independent prognostic factor. The multivariate analysis identified age of 70 years or older, pEM0, ne2,3 and postoperative adjuvant chemotherapy as showing a significant trend towards independent prognostic relevance.

CONCLUSION

The good news about resected distal bile duct carcinoma is that the percentage of those who achieved R0 resection has risen to 89.1%. Our multivariate analysis identified age of 70 years or older, pEM0, ne2,3 and postoperative adjuvant chemotherapy as prognostic factors. In order to improve the outcome of treatment, it is necessary to improve preoperative diagnostic imaging of pancreatic invasion and lymph node metastasis, establish the optimal operation range and clarify whether aortic lymph node dissection is needed to control lymph node metastasis, and establish effective regimens of chemotherapy.

Distal Bile Duct Cancer: Radical (R0 > 1 mm) Resection Achieves Favorable Survival

OBJECTIVE

Evaluation of the outcome after resection for distal bile duct cancer (DBC) with focus on the impact of microscopic histopathological resection status R0 (>1 mm) versus R1 (≤1 mm) vs R1 (direct).

SUMMARY BACKGROUND DATA

DBC is a rare disease for which oncologic resection offers the only chance of cure.

METHODS

Prospectively collected data of consecutive patients undergoing pancreaticoduodenectomy for DBC were analyzed. Histopathological resection status was classified according to the Leeds protocol for pancreatic ductal adeno carcinoma (PDAC) (PDAC; R0 >1 mm margin clearance vs R1 ≤1 mm vs R1 direct margin involvement).

RESULTS

A total of 196 patients underwent pancreaticoduodenectomy for DBC. Microscopic complete tumor clearance (R0>1 mm) was achieved in 113 patients (58%). Median overall survival (OS) of the entire cohort was 37 months (5- and 10-year OS rate: 40% and 31%, respectively). After R0 resection, median OS increased to 78 months with a 5-year OS rate of 52%. Negative prognostic factors were age >70 years ( P < 0.0001, hazard ratio (HR) 2.48), intraoperative blood loss >1000 mL ( P = 0.0009, HR 1.99), pN1 and pN2 status ( P = 0.0052 and P = 0.0006, HR 2.14 and 2.62, respectively) and American Society of Anesthesiologists score >II ( P = 0.0259, HR 1.61).

CONCLUSIONS

This is the largest European single-center study of surgical treatment for DBC and the first to investigate the prognostic impact of the revised PDAC resection status definition in DBC. The results show that this definition is valid in DBC and that "true" R0 resection (>1 mm) is a key factor for excellent survival. In contrast to PDAC, there was no survival difference between R1 (≤1 mm) and R1 (direct).

The T Category of Distal Extrahepatic Bile Duct Carcinoma: A Comparative Analysis With Invasive Tumor Thickness

The T category of distal extrahepatic bile duct carcinoma (DBDC) is based on invasion depth from the basal lamina to the deepest infiltrating tumor cells. Recently, invasive tumor thickness (ITT) was proposed, defined as maximal vertical distance of invasive tumor components regardless of the basal lamina. We compared the predictive value of T category, and ITT grading in 424 surgically resected DBDCs. DBDCs were categorized as 6 Tis (1.4%), 134 T1 (<5 mm; 31.6%), 204 T2 (5 to 12 mm; 48.1%), and 80 T3 (>12 mm; 18.9%). With ITT, there were 6 G0 (no invasion; 1.4%), 3 G1 (<1 mm; 0.7%), 90 G2 (≥1 and <5 mm; 21.2%), 188 G3 (≥5 and <10 mm; 44.4%), and 137 G4 (≥10 mm; 32.3%). The 5-year survival rates of T1, T2, and T3 were 58.9%, 44.2%, and 18.2%, and those of ITT G1, G2, G3, and G4 were 33.3%, 54.1%, 51.6%, and 26.7%, respectively. The T category discriminated patient survival by overall (P<0.001) and pairwise (T1 vs. T2, P=0.007; T2 vs. T3, P<0.001) comparisons. ITT grading distinguished survival by overall and between G3-G4 (both P<0.001), with no survival differences observed between G1-G2 and G2-G3 comparisons. The T category more accurately discriminated patient survival than ITT grading. To determine the T category for DBDCs, (1) longitudinal sectioning on gross examination, especially for DBDCs with large papillary or nodular growth patterns; (2) evaluation of serial sections or alternative hematoxylin and eosin slides; (3) use of a straight or curved baseline depending on the shape of the peritumoral normal bile duct wall and/or the basal lamina of the peritumoral normal biliary epithelia/biliary intraepithelial neoplasias are recommended.

Development and external validation of a prediction model for overall survival after resection of distal cholangiocarcinoma

BACKGROUND

Various prognostic factors are associated with overall survival (OS) after resection of distal cholangiocarcinoma (dCCA). The objective of this study was to develop and validate a prediction model for 3-year OS after pancreatoduodenectomy for dCCA.

METHODS

The derivation cohort consisted of all patients who underwent pancreatoduodenectomy for dCCA in the Netherlands (2009-2016). Clinically relevant variables were selected based on the Akaike information criterion using a multivariate Cox proportional hazards regression model, with model performance being assessed by concordance index (C-index) and calibration plots. External validation was performed using patients from the Belgium Cancer Registry (2008-2016), and patients from two university hospitals of Southampton (U.K.) and Verona (Italy).

RESULTS

Independent prognostic factors for OS in the derivation cohort of 454 patients after pancreatoduodenectomy for dCCA were age (HR 1.02, 95% CI 1.01-1.03), pT (HR 1.43, 95% CI 1.07-1.90) and pN category (pN1: HR 1.78, 95% CI 1.37-2.32; pN2: HR 2.21, 95% CI 1.63-3.01), resection margin status (HR 1.79, 95% CI 1.39-2.29) and tumour differentiation (HR 2.02, 95% CI 1.62-2.53). The prediction model was based on these prognostic factors. The optimism-adjusted C-indices were similar in the derivation cohort (0.69), and in the Belgian (0.66) and Southampton-Verona (0.68) validation cohorts. Calibration was accurate in the Belgian validation cohort (slope = 0.93, intercept = 0.12), but slightly less optimal in the Southampton-Verona validation cohort (slope = 0.88, intercept = 0.32). Based on this model, three risk groups with different prognoses were identified (3-year OS of 65.4%, 33.2% and 11.8%).

CONCLUSIONS

The prediction model for 3-year OS after resection of dCCA had reasonable performance in both the derivation and geographically external validation cohort. Calibration slightly differed between validation cohorts. The model is readily available via www. pancreascalculator.com to inform patients from Western European countries on their prognosis, and may be used to stratify patients for clinical trials.

Comparison of Four Lymph Node Stage Methods for Predicting the Prognosis of Distal Cholangiocarcinoma Patients After Surgery

Background

The metastatic status of regional lymph nodes is an effective risk factor for the prognosis of distal cholangiocarcinoma (dCCA). But existing lymph node staging is not accurate enough and is susceptible to interference. This study aims to explore the predictive ability of the log odds of positive lymph nodes (LODDS) staging system of dCCA compared with existing lymph node staging systems.

Methods

A total of 928 dCCA patients were selected from the Surveillance, Epidemiology, and End Results (SEER) database as the training cohort, and 207 dCCA patients from West China Hospital who underwent surgery were reviewed as the validation cohort. The least absolute shrinkage and selection operator (LASSO) and multivariate Cox regression were conducted to identify the most meaningful factors relevant to prognosis. The performance of four lymph node stage systems was compared by a model-based approach.

Result

Age at diagnosis, pathological grade, American Joint Committee on Cancer (AJCC) tumor 7th T stage, tumor size, radiotherapy, chemotherapy, and lymph node stage system were independent prognostic factors. The model with the LODDS system had a better model fit with the highest C-index (0.679) and 1-/3-/5- area under the receiver operating characteristic curve (AUC) (0.739/0.671/0.658) as well as the lowest Akaike information criterion (AIC) (5,020.52). External validation results from 207 dCCA patients showed a C-index of 0.647 and 1-/3-/5-AUC of 0.740/0.683/0.589. Compared with the lymph node ratio (LNR), AJCC 8th N system, and 7th N system, the 5-year net reclassification improvement (NRI) of the LODDS system was 0.030 (95% CI: -0.079 to 0.147), 0.042 (95% CI: -0.062 to 0.139), and 0.040 (95% CI: -0.057 to 0.146), respectively. The integrated discrimination improvement (IDI) of LODDS improved compared with the LNR model (0.016; 95% CI: -0.001 to 0.036), AJCC 8th N system (0.020; 95% CI: 0.003-0.037), and AJCC 7th N system (0.019; 95% CI: 0.002-0.036). Decision curve analysis (DCA) also shows a greater net benefit of LODDS. In lymph node-negative patients, LODDS reveals a positive linear relationship with the hazard ratio (HR). The stage capacity of LODDS in a subgroup analysis stratified by examined lymph node number (ELNN) was consistent.

Conclusions

The LODDS lymph node stage system has superior predictive performance as compared with the LNR, AJCC 7th, and 8th lymph node stage systems. Meanwhile, LODDS has a more detailed staging ability and good stability.

The evaluation of the 8th and 7th edition of the American joint committee on cancer tumor classification for distal cholangiocarcinoma: the proposal of a modified new tumor classification

BACKGROUND

The 7th and 8th editions of the American Joint Committee on Cancer (AJCC) tumor (T) classification of distal cholangiocarcinoma (DCC), which are based on either layer or depth, may not accurately stratify patient survival.

METHODS

A total of 121 patients who underwent resection for DCC between 2002 and 2016 were analyzed. The impact of the AJCC staging system on survival was examined and a new T classification was established based on independent prognostic factors.

RESULTS

Regarding overall survival, the optimal depth of invasion (DOI) cut-off value (8 mm) was the only independent prognostic factor. Regarding the relapse-free survival (RFS), a DOI >8 mm, portal vein (PV) invasion, and duodenal or pancreatic invasion were independent prognostic factors. A new T classification was developed as follows: T1, no invasion of adjacent organs; T2, invasion of the duodenum or pancreas; T3, invasion >8 mm into the bile duct wall; and T4, invasion of the PV or arteries. There were no significant differences in RFS according to the 8th edition of the AJCC. However, significant differences were observed in the RFS between T1 and T2 and between T2 and T3.

CONCLUSION

A new T classification based on the layer and depth may be more feasible.

Stratification of Postoperative Prognosis by Invasive Tumor Thickness in Perihilar Cholangiocarcinoma

BACKGROUND

The pathological tumor classification of distal cholangiocarcinoma in the American Joint Committee on Cancer (AJCC) Cancer Staging Manual 8th edition is based on invasive depth, whereas that of perihilar cholangiocarcinoma (PHCC) continues to be layer-based. We aimed to clarify whether invasive depth measurement based on invasive tumor thickness (ITT) could help determine postoperative prognosis in patients with PHCC.

METHODS

We enrolled 184 patients with PHCC who underwent hepatectomy plus extrahepatic bile duct resection or hepatopancreatoduodenectomy with curative intent. ITT was measured using simple definitions according to the sectioning direction or gross tumor pattern.

RESULTS

The median ITT was 5.8 mm (range 0.7-15.5). Using the recursive partitioning technique, ITT was classified into grades A (ITT < 2 mm, n = 9), B (2 mm ≤ ITT < 5 mm, n = 68), C (5 mm ≤ ITT < 11 mm, n = 81), and D (11 mm < ITT, n = 26). The median survival times (MSTs) in patients with grade B, C, or D were 90.8, 44.6, and 21.1 months, respectively (patients with grade A did not reach the MST). There were significant differences in postoperative prognosis between ITT grades (A vs. B, p = 0.027; B vs. C, p < 0.001; C vs. D, p = 0.004). Through multivariate analysis, regional node metastasis, invasive carcinoma at the resected margin, and ITT grade were determined as independent prognostic factors.

CONCLUSION

ITT could be measured using simple methods and may be used to stratify postoperative prognosis in patients with PHCC.

Prognostic impact of the number of metastatic lymph nodes in distal bile duct cancer: An analysis of Japanese registration cases by the study group for biliary surgery of the Japanese Society of Hepato-Biliary-Pancreatic Surgery

BACKGROUND

Lymph node metastasis is an important prognostic factor for distal bile duct cancer. The number of lymph node metastases was adopted for nodal classification. However, different cutoff values have been proposed, ranging from two to five.

METHODS

A total of 1748 cases who underwent curative surgery with pancreatoduodenectomy for distal bile duct cancer registered in the nationwide biliary tract cancer registry in Japan from 2008 to 2013 were included. Univariate Cox regression was performed to assess the effect of prognostic lymph node metastasis counts on mortality and to determine cutoff values.

RESULTS

The overall survival rate after resection was 47.4% at 5 years. Univariate and multivariate analysis found prognostic factors to include lymph node metastasis. The cutoff point was set to two lymph node metastases using the Cox model. There were significant differences in pairwise comparisons between three groups by the number of metastatic lymph node (P < .001 for 0 vs 1-2 and P = .003 for 1-2 vs ≥3).

CONCLUSION

Our data suggest lymph node classification as N0 (patients without lymph node metastases), N1 (metastasis in 1-2 regional lymph nodes), and N2 (metastases in ≥3 regional lymph nodes).

Proposed Modification of Staging for Distal Cholangiocarcinoma Based on the Lymph Node Ratio Using Korean Multicenter Database

The 8th American Joint Committee on Cancer (AJCC) staging system for distal cholangiocarcinoma (DCC) included a positive lymph node count (PLNC), but a comparison of the prognostic predictive power of PLNC and lymph node ratio (LNR) is still under debate. This study aimed to compare various staging models made by combining the abovementioned factors, identify the model with the best predictive power, and propose a modified staging system. We retrospectively reviewed 251 patients who underwent surgery for DCC at four centers. To determine the superiority of various staging models for predicting overall OSR, Akaike information criterion (AIC), Bayesian information criterion (BIC), AIC correction (AICc), and Harrell’s C-statistic were calculated. In multivariate analysis, age (p = 0.003), total lymph node count (p = 0.033), and revised T(LNR)M staging (p < 0.001) were identified as independent factors for overall survival rate. The predictive performance of revised T (LNR) M staging (AIC: 1288.925, BIC: 1303.377, AICc: 1291.52, and Harrell’s C statics: 0.667) was superior to other staging system. A modified staging system consisting of revised T category and LNR predicted better overall survival of DCC than AJCC 7th and AJCC 8th editions. In the future, external validation of the proposed new system using a larger cohort will be required.

Validation of the T category for distal cholangiocarcinoma: Measuring the depth of invasion is complex but correlates with survival

According to the current 8th edition of the American Joint Committee of Cancer (AJCC), the T category of distal cholangiocarcinomas is classified based on the depth of invasion (DOI) (T1, < 5 mm; T2, between 5 and 12 mm; T3, > 12 mm). In consideration of the discrepancies between previous studies about the prognostic significance, we aimed to validate the current AJCC T staging system of distal cholangiocarcinomas. DOI was measured using three different methods: DOI1, DOI2, and DOI3. DOI1 was defined and stratified according to the AJCC 8th edition. DOI2 was measured as the distance from an imaginary curved line approximated along the distorted mucosal surface to the deepest invasive tumor cells. DOI3 was defined as the total tumor thickness. DOI2 and DOI3 were also divided into three categories using the same cut-off points as in the AJCC 8th edition. We compared these three DOI methods to the AJCC 7th edition as well. In contrast with the AJCC 7th edition, all three groups showed a correlation with patients' overall survival. Above all, the DOI2 group demonstrated the best significance in multivariate analysis. However, when the C indices were compared between these groups, differential significance proved to be negligible (DOI1 vs DOI2, p = 0.915; DOI2 vs DOI3, p = 0.057). Therefore, the measurement of DOI does not need to be rigorously and stringently performed. In conclusion, we showed that the current T classification system better correlates with the overall survival of patients with distal cholangiocarcinomas than the previous system.

Proposal of the minimal number of retrieved regional lymph nodes for accurate staging of distal bile duct cancer and clinical validation of the three-tier lymph node staging system (AJCC 8th edition)

BACKGROUND

The minimal required number of retrieved lymph nodes (MNRLNs) to enable accurate staging of distal bile duct (DBD) adenocarcinoma remains unclear. The three-tier 8th N staging system of the American Joint Committee on Cancer (AJCC) for DBD adenocarcinoma has been recently released. The present study is aimed at proposing the MNRLNs for accurate staging and validating the 8th N stage.

METHODS

Between 1991 and 2015, patients with pathologically confirmed DBD adenocarcinoma who underwent pancreatoduodenectomy were enrolled. MNRLN was calculated via a log-rank test based on cut-off values. The concordance index (C-index) was utilized to compare the discrimination capability of the two- and three-tier N stages.

RESULTS

A total of 780 patients were enrolled. Lymph node (LN) positivity and 5-year overall survival (5-YOS) rates stabilized and significant survival differences between node-negative and -positive patients were observed when ≥12 LNs were retrieved. 5-YOS rates between each 8th N stage significantly differ (N0 vs. N1, P = 0.037; N1 vs. N2, P = 0.003). The C-index of the 8th N stage was higher than that of the 7th (0.59 vs. 0.57).

CONCLUSIONS

For accurate staging, at least 12 LNs should be retrieved. The three-tier N staging system is valid for clinical practice and has a more accurate prognostic predictability than the two-tier system.

Proposal for a new classification for perihilar cholangiocarcinoma based on tumour depth

Background

The T system for distal cholangiocarcinoma has been revised from a layer-based to a depth-based approach in the current American Joint Committee on Cancer (AJCC) classification. In perihilar cholangiocarcinoma, tumour depth in the staging scheme has not yet been addressed. The aim of this study was to propose a new T system using measured tumour depth in perihilar cholangiocarcinoma.

Methods

Patients who underwent hepatectomy for perihilar cholangiocarcinoma between 2001 and 2014 were reviewed retrospectively. The vertical distance between the top of the tumour and deepest invasive cells was measured as invasive tumour thickness (ITT) by two independent pathologists. Log rank statistics were used to determine cut-off points, and the concordance (C) index was used to assess survival discrimination of each T system.

Results

ITT was measurable in all 440 patients, with a median value of 6·0 (range 0–45) mm. The median difference in ITT between observers was 0·6 (range 0–20) mm. Cut-off points for prognosis were 1, 5 and 8 mm. Five-year survival decreased with increasing ITT (P &lt; 0·001): 67 per cent for ITT less than 1 mm (25 patients), 54·9 per cent for ITT 1 mm and over to less than 5 mm (138 patients), 43·4 per cent for ITT 5 mm and over to less than 8 mm (118 patients), and 32·2 per cent for ITT 8 mm and over (159 patients). The C-index of this classification was comparable to that of the current AJCC T classification (0·598 versus 0·589).

Conclusion

ITT is a reliable approach for making a depth assessment in perihilar cholangiocarcinoma. A four-tier ITT classification with cut-off points of 1, 5 and 8 mm is an adequate alternative to the current layer-based T classification.

Dual-organ invasion is associated with a lower survival rate than single-organ invasion distal bile duct cancer: A multicenter study

The revised criteria of the 8^th American Joint Committee on Cancer (AJCC) cancer staging system consider depth of invasion as one of the factors that determine stage in distal bile duct (DBD) cancer, but exclude adjacent organ invasion. The aims were to evaluate the association between adjacent organ invasion and relapse-free survival (RFS) and overall survival (OS) after curative surgical resection of DBD cancer and to propose optimal criteria for predicting clinical outcomes. In this retrospective cohort study, 378 patients with DBD cancer treated in multi-institutions between 1996 and 2013 were investigated. This study evaluated the relationship between clinicopathologic parameters and adjacent organ invasion and used organ invasion to compare the survival times of each group. Among 204 patients with adjacent organ invasion, 152 were in the single-organ invasion group and 52 were in the dual-organ invasion group based on a review of microscopic slides. In univariate and multivariate analyses, patients with dual-organ invasion had a shorter RFS and OS time than those with single-organ invasion. Organ invasion should be included as one of the factors that determine the AJCC stage; this might ultimately help to predict better the survival rate of patients with DBD cancer.

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.

Validation of the Eighth American Joint Committee on Cancer Staging System for Distal Bile Duct Carcinoma

PURPOSE

T category of the eighth edition of the American Joint Committee on Cancer (AJCC) staging system for distal bile duct carcinoma (DBDC) was changed to include tumor invasion depth measurement, while the N category adopted a 3-tier classification system based on the number of metastatic nodes.

Materials and Methods

To validate cancer staging, a total of 200 surgically resected DBDCs were staged and compared according to the seventh and eighth editions.

RESULTS

T categories included T1 (n=37, 18.5%), T2 (n=114, 57.0%), and T3 (n=49, 24.5%). N categories included N0 (n=133, 66.5%), N1 (n=50, 25.0%), and N2 (n=17, 8.5%). Stage groupings included I (n=33, 16.5%), II (n=150, 75.0%), and III (n=17, 8.5%). The overall 5-year survival rates (5-YSRs) of T1, T2, and T3 were 59.3%, 42.4%, and 12.2%, respectively. T category could discriminate patient survival by both pairwise (T1 and T2, p=0.011; T2 and T3, p < 0.001) and overall (p < 0.001) comparisons. The overall 5-YSRs of N0, N1, and N2 were 47.3%, 17.0%, and 14.7%, respectively. N category could partly discriminate patient survival by both pairwise (N0 and N1, p < 0.001; N1 and N2, p=0.579) and overall (p < 0.001) comparisons. The overall 5-YSRs of stages I, II, and III were 59.0%, 35.4%, and 14.7%, respectively. Stages could distinguish patient survival by both pairwise (I and II, p=0.002; II and III, p=0.015) and overall (p < 0.001) comparisons. On multivariate analyses, T and N categories (p=0.014 and p=0.029) and pancreatic invasion (p=0.006) remained significant prognostic factors.

CONCLUSION

The T andNcategories of the eighth edition AJCC staging system for DBDC accurately predict patient prognosis.

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.

Eighth Edition of the UICC Classification of Malignant Tumours: an overview of the changes in the pathological TNM classification criteria-What has changed and why?

The TNM classification of malignant tumours is a mainstay tool in clinical practice and research for prognostic assessment of patients, treatment allocation and trial enrolment, as well as for epidemiological studies and data collection by cancer registries worldwide. Pathological TNM (pTNM) represents the pathological classification of a tumor, assigned after surgical resection or adequate sampling by biopsy, and periodical updates to the relative classification criteria are necessary to preserve its clinical relevance by integrating newly reported data. A structured approach has been put in place to fulfil this need and, based upon this process, the Eighth Edition of Union for International Cancer Control (UICC) TNM Classification of Malignant Tumours has been published, introducing many significant changes, including novel classification criteria for specific tumour types. In this review, we aim to describe the major changes introduced in the pTNM classification criteria and to summarize the evidence supporting these changes.

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.

Survival outcome and prognostic factors after pancreatoduodenectomy for distal bile duct carcinoma: a retrospective multicenter study

PURPOSE

Pancreatoduodenectomy is the most common operative procedure performed for distal bile duct carcinoma. Data on outcome after surgery for this rare malignancy is scarce, especially from western countries. The purpose of this study is to explore the prognostic factors and outcome after pancreatoduodenectomy for distal bile duct carcinoma.

METHODS

Patients receiving pancreatoduodenectomy for distal bile duct carcinoma were identified from institutional databases of five German and one Russian academic centers for pancreatic surgery. Univariable and multivariable general linear model, Kaplan-Meier method, and Cox regression were used to identify prognostic factors for postoperative mortality and overall survival.

RESULTS

N = 228 patients operated from 1994 to 2015 were included. Reoperation (OR 5.38, 95%CI 1.51-19.22, p = 0.010), grade B/C postpancreatectomy hemorrhage (OR 3.73, 95%CI 1.13-12.35, p = 0.031), grade B/C postoperative pancreatic fistula (OR 4.29, 95%CI 1.25-14.72, p = 0.038), and advanced age (OR 4.00, 95%CI 1.12-14.03, p = 0.033) were independent risk factors for in-hospital mortality in multivariable analysis. Median survival was 29 months, 5-year survival 27%. Positive resection margin (HR 2.07, 95%CI 1.29-3.33, p = 0.003), high tumor grade (HR 1.71, 95%CI 1.13-2.58, p = 0.010), lymph node (HR 1.68, 95%CI 1.13-2.51, p = 0.011), and distant metastases (HR 2.70, 95%CI 1.21-5.58, p = 0.014), as well as severe non-fatal postoperative complications (HR 1.64, 95%CI 1.04-2.58, p = 0.033) were independent negative prognostic factors for survival in multivariable analysis.

CONCLUSION

Distant metastases and positive resection margin are the strongest negative prognostic factors for survival after pancreatoduodenectomy for distal bile duct carcinoma; thus, surgery with curative intent is only warranted in patients with local disease, where R0 resection is feasible.