Validation of a prognostic nomogram in patients undergoing resection for pancreatic ductal adenocarcinoma in a UK tertiary referral centre

Proposal of nomograms to predict clinical outcomes in patients with ampulla of Vater cancer based on the Korea-Japan collaborative study

BACKGROUND

In this study, we aimed to develop and validate a nomogram to predict overall survival (OS) and recurrence-free survival (RFS) in patients who underwent curative resection of ampulla of Vater (AOV) cancer. This is the first study for nomograms in AOV cancer patients using retrospective data based on an international multicenter study.

METHODS

A total of 2007 patients with AOV adenocarcinoma who received operative therapy between 2002 January and 2015 December in Korea and Japan were retrospectively assessed to develop a prediction model. Nomograms for 5-year OS and 3-year RFS were constructed by dividing the patients who received and who did not receive adjuvant therapy after surgery, respectively. Significant risk factors were identified by univariate and multivariate Cox analyses. Performance assessment of the four prediction models was conducted by the Harrell's concordance index (C-index) and calibration curves using bootstrapping.

RESULTS

A total of 2007 and 1873 patients were collected for nomogram construction to predict 5-year OS and 3-year RFS. We developed four types of nomograms, including models for 5-year OS and 3-year RFS in patients who did not receive postoperative adjuvant therapy, and 5-year OS and 3-year RFS in patients who received postoperative adjuvant therapy. The C-indices of these nomograms were 0.795 (95% confidence interval [CI]: 0.766-0.823), 0.712 (95% CI: 0.674-0.750), 0.804 (95% CI: 0.7778-0.829), and 0.703 (95% CI: 0.669-0.737), respectively.

CONCLUSIONS

This predictive model could help clinicians to choose optimal treatment and precisely predict prognosis in AOV cancer patients.

Prognostic models to predict survival in patients with pancreatic cancer: a systematic review

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) has poor survival. Current treatments offer little likelihood of cure or long-term survival. This systematic review evaluates prognostic models predicting overall survival in patients diagnosed with PDAC.

METHODS

We conducted a comprehensive search of eight electronic databases from their date of inception through to December 2019. Studies that published models predicting survival in patients with PDAC were identified.

RESULTS

3297 studies were identified; 187 full-text articles were retrieved and 54 studies of 49 unique prognostic models were included. Of these, 28 (57.1%) were conducted in patients with advanced disease, 17 (34.7%) with resectable disease, and four (8.2%) in all patients. 34 (69.4%) models were validated, and 35 (71.4%) reported model discrimination, with only five models reporting values >0.70 in both derivation and validation cohorts. Many (n = 27) had a moderate to high risk of bias and most (n = 33) were developed using retrospective data. No variables were unanimously found to be predictive of survival when included in more than one study.

CONCLUSION

Most prognostic models were developed using retrospective data and performed poorly. Future research should validate instruments performing well locally in international cohorts and investigate other potential predictors of survival.

International validation and update of the Amsterdam model for prediction of survival after pancreatoduodenectomy for pancreatic cancer

BACKGROUND

The objective of this study was to validate and update the Amsterdam prediction model including tumor grade, lymph node ratio, margin status and adjuvant therapy, for prediction of overall survival (OS) after pancreatoduodenectomy for pancreatic cancer.

METHODS

We included consecutive patients who underwent pancreatoduodenectomy for pancreatic cancer between 2000 and 2017 at 11 tertiary centers in 8 countries (USA, UK, Germany, Italy, Sweden, the Netherlands, Korea, Australia). Model performance for prediction of OS was evaluated by calibration statistics and Uno's C-statistic for discrimination. Validation followed the TRIPOD statement.

RESULTS

Overall, 3081 patients (53% male, median age 66 years) were included with a median OS of 24 months, of whom 38% had N2 disease and 77% received adjuvant chemotherapy. Predictions of 3-year OS were fairly similar to observed OS with a calibration slope of 0.72. Statistical updating of the model resulted in an increase of the C-statistic from 0.63 to 0.65 (95% CI 0.64-0.65), ranging from 0.62 to 0.67 across different countries. The area under the curve for the prediction of 3-year OS was 0.71 after updating. Median OS was 36, 25 and 15 months for the low, intermediate and high risk group, respectively (P < 0.001).

CONCLUSIONS

This large international study validated and updated the Amsterdam model for survival prediction after pancreatoduodenectomy for pancreatic cancer. The model incorporates readily available variables with a fairly accurate model performance and robustness across different countries, while novel markers may be added in the future. The risk groups and web-based calculator www.pancreascalculator.com may facilitate use in daily practice and future trials.

Preoperative Clinical and Computed Tomography (CT)-Based Nomogram to Predict Oncologic Outcomes in Patients with Pancreatic Head Cancer Resected with Curative Intent: A Retrospective Study

Background: Currently, proposed nomograms are mainly based on post-operative histopathology. The purpose of this study was to identify preoperative computed tomography (CT) and clinical information that allow prediction of disease-free (DFS) and overall survival (OS) of patients surgically treated for pancreatic head cancer. Methods: A total of 136 patients who underwent curative-intent surgery were retrospectively reviewed. Based on results from multivariate Cox regression analysis, a prediction model was constructed with preoperative CT features and clinical information. Overall performance of the nomogram was calculated by Harrell’s C-index. Results: Symptoms at diagnosis, preoperative serum CA 19-9 ≥ 34 U/mL, and four imaging features (necrosis (DFS, P = 0.066; OS, P = 0.002), possible venous invasion (DFS, P = 0.150, OS, P = 0.055), suspected metastatic regional lymph node (DFS, P = 0.001; OS, P = 0.099), and associated pancreatitis or pseudocyst (DFS, P = 0.013; OS, P = 0.041)) were included to build the nomogram. The c-statistics for the discrimination power of the proposed nomogram was 0.6496 for DFS and 0.6746 for OS. Conclusion: A nomogram derived from preoperative CT and clinical information could estimate the risk of recurrence and all-cause death after curative-intent surgery for radiologically resectable pancreatic head cancer.

Development and validation of a prognostic model to predict the prognosis of patients who underwent chemotherapy and resection of pancreatic adenocarcinoma: a large international population-based cohort study

BACKGROUND

Pancreatic cancer (PaC) remains extremely lethal worldwide even after resection. PaC resection rates are low, making prognostic studies in resected PaC difficult. This large international population-based study aimed at exploring factors associated with survival in patients with resected TNM stage I-II PaC receiving chemotherapy and at developing and internationally validating a survival-predicting model.

METHODS

Data of stage I-II PaC patients resected and receiving chemotherapy in 2003-2014 were obtained from the national cancer registries of Belgium, the Netherlands, Slovenia, and Norway, and the US Surveillance, Epidemiology, and End Results (SEER)-18 Program. Multivariable Cox proportional hazards models were constructed to investigate the associations of patient and tumor characteristics with overall survival, and analysis was performed in each country respectively without pooling. Prognostic factors remaining after backward selection in SEER-18 were used to build a nomogram, which was subjected to bootstrap internal validation and external validation using the European datasets.

RESULTS

A total of 11,837 resected PaC patients were analyzed, with median survival time of 18-23 months and 3-year survival rates of 21-31%. In the main analysis, patient age, tumor T stage, N stage, and differentiation were associated with survival across most countries, with country-specific association patterns and strengths. However, tumor location was mostly not significantly associated with survival. Resection margin, hospital type, tumor size, positive and harvested lymph node number, lymph node ratio, and comorbidity number were associated with survival in certain countries where the information was available. A median survival time- and 1-, 2-, 3-, and 5-year survival probability-predictive nomogram incorporating the backward-selected variables in the main analysis was established. It fits each European national cohort similarly well. Calibration curves showed very good agreement between nomogram-prediction and actual observation. The concordance index of the nomogram (0.60) was significantly higher than that of the T and N stage-based model (0.56) for predicting survival.

CONCLUSIONS

In these large international population-based cohorts, patients with resected PaC receiving chemotherapy have distinct characteristics independently associated with survival, with country-specific patterns and strengths. A robust benchmark population-based survival-predicting model is established and internationally validated. Like previous models predicting survival in resected PaC, our nomogram performs modestly.

Systematic review of clinical prediction models for survival after surgery for resectable pancreatic cancer

BACKGROUND

As more therapeutic options for pancreatic cancer are becoming available, there is a need to improve outcome prediction to support shared decision-making. A systematic evaluation of prediction models in resectable pancreatic cancer is lacking.

METHODS

This systematic review followed the CHARMS and PRISMA guidelines. PubMed, Embase and Cochrane Library databases were searched up to 11 October 2017. Studies reporting development or validation of models predicting survival in resectable pancreatic cancer were included. Models without performance measures, reviews, abstracts or more than 10 per cent of patients not undergoing resection in postoperative models were excluded. Studies were appraised critically.

RESULTS

After screening 4403 studies, 22 (44 319 patients) were included. There were 19 model development/update studies and three validation studies, altogether concerning 21 individual models. Two studies were deemed at low risk of bias. Eight models were developed for the preoperative setting and 13 for the postoperative setting. Most frequently included parameters were differentiation grade (11 of 21 models), nodal status (8 of 21) and serum albumin (7 of 21). Treatment-related variables were included in three models. The C-statistic/area under the curve values ranged from 0·57 to 0·90. Based on study design, validation methods and the availability of web-based calculators, two models were identified as the most promising.

CONCLUSION

Although a large number of prediction models for resectable pancreatic cancer have been reported, most are at high risk of bias and have not been validated externally. This overview of prognostic factors provided practical recommendations that could help in designing easily applicable prediction models to support shared decision-making.

Substaging of Lymph Node Status in Resected Pancreatic Ductal Adenocarcinoma Has Strong Prognostic Correlations: Proposal for a Revised N Classification for TNM Staging

BACKGROUND

The current tumor-node-metastasis staging system for the pancreas does not incorporate the number of lymph nodes (LNs) with metastasis.

METHODS

Among 1649 pancreaticoduodenectomies, 227 stringently defined pancreatic ductal adenocarcinomas (PDACs) that had undergone a specific approach of LN harvesting were analyzed for the prognostic value of LN substaging protocols used for other gastrointestinal (GI) organs.

RESULTS

The median number of LNs harvested was 18, and the median number of LNs with metastasis was 3. Lymph node metastasis was detected in 175 cases (77 %). The number of LNs involved correlated significantly with clinical outcome. When cases were substaged with the protocol already in use for the upper GI organs (N0: no metastasis, N1: metastasis to 1-2 LNs; N2: metastasis to ≥3 LNs), the median overall survival times were 35, 21, and 18 months, and the respective 3-year survival rates were 46, 34, and 20 % (p = 0.004). Analysis of the Surveillance, Epidemiology and End Results (SEER) database also confirmed the survival differences between these substages (median overall survival times of 23, 15, and 14 months and respective 3-year survival rates of 37, 22, and 18 %; p < 0.0001). The substaging protocol for the lower GI organs (N0: no metastasis; N1: metastasis to 1-3 LNs; N2: metastasis to ≥4 LNs) also was significant, with median overall survival times of 35, 21, 18 months and respective 3-year survival rates of 46, 26, and 23 %; p = 0.009). The association between higher N stage and shorter survival persisted with multivariate modeling for both protocols, although the prognostic value of the upper GI protocol appeared to be slightly stronger according to the Akaike Information Criterion method.

CONCLUSION

In conclusion, with proper LN harvesting, the LN metastasis rate in PDACs is very high (77 %). Substaging of LN metastasis has significant prognostic value and needs to be considered in the N staging of PDACs. The protocol already in use for other upper GI tract organs, which currently also is proven significant for ampulla, would be preferable, although the lower GI tract protocol also is applicable.

Identifying molecular subtypes related to clinicopathologic factors in pancreatic cancer

Background

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal tumors and usually presented with locally advanced and distant metastasis disease, which prevent curative resection or treatments. In this regard, we considered identifying molecular subtypes associated with clinicopathological factor as prognosis factors to stratify PDAC for appropriate treatment of patients.

Results

In this study, we identified three molecular subtypes which were significant on survival time and metastasis. We also identified significant genes and enriched pathways represented for each molecular subtype. Considering R0 resection patients included in each subtype, metastasis and survival times are significantly associated with subtype 1 and subtype 2.

Conclusions

We observed three PDAC molecular subtypes and demonstrated that those subtypes were significantly related with metastasis and survival time. The study may have utility in stratifying patients for cancer treatment.

Conditional survival in pancreatic cancer: better than expected

BACKGROUND

Traditional survival estimates after resection for pancreatic cancer are based on clinicopathological variables at the time of diagnosis. Estimates have not reflected time survived after resection, as investigated for other malignancies. The aim of the present study was to understand how survival estimates change after pancreatic resection for cancer based on time already survived (conditional survival).

METHODS

Pancreatectomies performed for pancreatic ductal adenocarcinoma (PDAC) between 2001 and 2010 were reviewed. Clinicopathological variables were evaluated to identify predictors of survival. Expected survival according to a validated nomogram for pancreatic cancer as well as conditional survival estimates and actual survival were calculated.

RESULTS

In all, 186 patients underwent pancreatic resection for PDAC [154 (82.8%) Whipple, 26 (14.0%) distal and 6 (3.2%) total]. Median (range) survival was 22 (3.4-107.3) months. Predictors of overall survival were: absence of nodal disease [odds ratio (OR) 8.8], age <67 years (OR 8.4) and lower stage (OR 4.3). Expected survival according to the nomogram was 70% (1 year), 39.5% (2 years) and 24% (3 years). As time passed, and overall and expected survival decreased, conditional survival increased.

DISCUSSION

The available prognostic system for PDAC underestimated survival compared with actual survival in the present study. Conditional survival estimates, based on accrued lifespan, were better than either predicted or actual survival, suggesting that survival is a dynamic, rather than static, concept. Conditional survival may, therefore, be a useful tool to allow patients and clinicians to project subsequent survival based on time accrued since resection.

Invasive carcinoma arising in intraductal papillary mucinous neoplasms of the pancreas: a matched control study with conventional pancreatic ductal adenocarcinoma

OBJECTIVE

The purpose of this study was to characterize the clinicopathological features of invasive carcinomas arising in intraductal papillary mucinous neoplasms of the pancreas (IPMN) by histological subtype of the invasive component and to compare the outcomes of these patients to a cohort of matched patients with conventional ductal pancreatic adenocarcinoma.

BACKGROUND

Two distinct histological subtypes of invasive carcinomas arising in IPMNs have been described, colloid carcinoma and tubular carcinoma. Previous reports have suggested prognostic differences between these 2 subtypes but a matched comparison of colloid carcinoma, tubular carcinoma, and conventional pancreatic adenocarcinoma has not been reported.

METHODS

The clinicopathological variables of 59 patients resected for an invasive component of IPMN were analyzed with detailed pathologic review of histopathologic subtype (colloid carcinoma and tubular carcinoma). Using a postresection pancreatic adenocarcinoma nomogram, patients with either tubular or colloid carcinoma were matched on a 1:1 basis with patients resected for conventional ductal pancreatic adenocarcinoma. Clinicopathological factors and overall outcome was analyzed between the matched groups.

RESULTS

Fifty-nine patients underwent resection for IPMN with an associated invasive carcinoma (IPMN-INV). The estimated 3- and 5-year survival rates were 76% and 68%, respectively. Tubular carcinoma was present in 35 patients (59%) and 24 patients (41%) had colloid carcinoma. Tubular carcinoma subtype [hazard ratio (HR) 3.7, 95% confidence interval (CI) 1.2-11.6] and the presence of positive regional lymph nodes (HR 3.2 95% CI 1.2-8.2) were clinicopathological factors predictive of decreased survival by multivariate analysis. The 5-year estimated survival rates for tubular carcinoma and colloid carcinoma were 55% and 87%, respectively (P = 0.01). When compared with patients with conventional ductal pancreatic ductal adenocarcinoma resected during the same time period matched by a prognostic nomogram, patients with colloid carcinoma had a significantly longer survival outcome compared with patients with conventional adenocarcinoma (P = 0.0001). By contrast, survival after resection between patients with the tubular subtype (3-year estimated survival, 61%) and the matched group with conventional adenocarcinoma (3-year estimated survival, 21%) (P = 0.87) was not statistically different.

CONCLUSIONS

In this study, the colloid carcinoma histological subtype of invasive IPMN had a more statistically favorable survival outcome than the tubular subtype. Patients with invasive tubular IPMN had no statistically significant difference in survival as matched patients with conventional ductal pancreatic carcinoma.