Precancerous neoplastic cells can move through the pancreatic ductal system.

Most adult carcinomas develop from noninvasive precursor lesions, a progression that is supported by genetic analysis. However, the evolutionary and genetic relationships among co-existing lesions are unclear. Here we analysed the somatic variants of pancreatic cancers and precursor lesions sampled from distinct regions of the same pancreas. After inferring evolutionary relationships, we found that the ancestral cell had initiated and clonally expanded to form one or more lesions, and that subsequent driver gene mutations eventually led to invasive pancreatic cancer. We estimate that this multi-step progression generally spans many years. These new data reframe the step-wise progression model of pancreatic cancer by illustrating that independent, high-grade pancreatic precursor lesions observed in a single pancreas often represent a single neoplasm that has colonized the ductal system, accumulating spatial and genetic divergence over time.

Multidisciplinary management of locally advanced pancreatic adenocarcinoma: Biology is King.

The annual incidence of pancreatic cancer is nearly 50,000 patients. The 5-year overall survival is only 9%, and there remains a great need for better therapy. A subset of these patients presents with locally advanced disease. Multidisciplinary therapy has evolved to include some combination of systemic chemotherapy, locoregional radiation, and surgery in select patients with excellent biology. This review will address the thoughtful evidence-based and individualized approach to these patients.

Preoperative risk prediction for intraductal papillary mucinous neoplasms by quantitative CT image analysis.

BACKGROUND: Intraductal papillary mucinous neoplasms (IPMNs) are radiographically identifiable potential precursor lesions of pancreatic adenocarcinoma. While resection is recommended when main duct dilation is present, management of branch duct IPMN (BD-IPMN) remains controversial. This study sought to evaluate whether preoperative quantitative imaging features of BD-IPMNs could distinguish low-risk disease (low- and intermediate-grade dysplasia) from high-risk disease (high-grade dysplasia and invasive carcinoma). METHODS: Patients who underwent resection between 2005 and 2015 with pathologically proven BD-IPMN and a preoperative CT scan were included in the study. Quantitative image features were extracted using texture analysis and a novel quantitative mural nodularity feature developed for the study. Significant features on univariate analysis were combined with clinical variables to build a multivariate prediction model. RESULTS: Within the study group of 103 patients, 76 (74%) had low-risk disease and 27 (26%) had high-risk disease. Quantitative imaging features were prognostic of low-vs. high-risk disease. The model based only on clinical variables achieved an AUC of 0.67 and 0.79 with the addition of quantitative imaging features. CONCLUSION: Quantitative image analysis of BD-IPMNs is a novel method that may enable risk stratification. External validation may provide a reliable non-invasive prognostic tool for clinicians.

Endoscopic versus percutaneous drainage of post-operative peripancreatic fluid collections following pancreatic resection.

BACKGROUND: Post-operative peripancreatic fluid collection (PFC) is a common complication following pancreatic resection which can be managed with endoscopic or percutaneous drainage. METHODS: Patients who underwent either endoscopic or percutaneous drainage of post-operative PFC were extracted from a prospectively-maintained database. The two groups were matched for surgery type, presence of a surgical drain and timing of drainage. RESULTS: Thirty-nine matched patients were identified in each group with a median age of 62 years. For primary drainage, technical success was achieved in almost all patients in both endoscopic and percutaneous groups (100% and 97%, p = NS); clinical success was achieved in 67% and 59%, respectively (p = 0.63). At least one "salvage" drainage procedure was required in 13 endoscopic patients versus 16 in the percutaneous group. Clinical success was achieved following the first salvage. Procedure in 85% of the endoscopic patients and 88% of the percutaneous patients (p = 0.62). Stent/drain duration (59 vs 33 days, p < 0.001) and number of post-procedural CT studies (2 vs 1, p = 0.02) were significantly higher in the endoscopic group. There was no difference in length of stay, complication, or recurrence between the two groups. CONCLUSION: Endoscopic drainage of post-operative PFC appears to be safe and effective with comparable success rates and outcomes to percutaneous drainage.

Development and Validation of a Multi-institutional Preoperative Nomogram for Predicting Grade of Dysplasia in Intraductal Papillary Mucinous Neoplasms (IPMNs) of the Pancreas: A Report from The Pancreatic Surgery Consortium.

OBJECTIVE: Previous nomogram models for patients undergoing resection of intraductal papillary mucinous neoplasms (IPMNs) have been relatively small single-institutional series. Our objective was to improve upon these studies by developing and independently validating a new model using a large multiinstitutional dataset. SUMMARY BACKGROUND DATA: IPMNs represent the most common radiographically identifiable precursor lesions of pancreatic cancer. They are a heterogenous group of neoplasms in which more accurate markers of high-grade dysplasia or early invasive carcinoma could help avoid unnecessary surgery in 1 case and support potentially curative intervention (resection) in another. METHODS: Prospectively maintained databases from 3 institutions were queried for patients who had undergone resection of IPMNs between 2005 and 2015. Patients were separated into main duct [main and mixed-type (MD)] and branch duct (BD) types based on preoperative imaging. Logistic regression modeling was used on a training subset to develop 2 independent nomograms (MD and BD) to predict low-risk (low- or intermediate-grade dysplasia) or high-risk (high-grade dysplasia or invasive carcinoma) disease. Model performance was then evaluated using an independent validation set. RESULTS: We identified 1028 patients who underwent resection for IPMNs [MD: n = 454 (44%), BD: n = 574 (56%)] during the 10-year study period. High-risk disease was present in 487 patients (47%). Patients with high-risk disease comprised 71% and 29% of MD and BD groups, respectively (P <0.0001). MD and BD nomograms were developed on the training set [70% of total (n = 720); MD: n = 318, BD: n = 402] and validated on the test set [30% (n = 308); MD: n = 136, BD: n = 172]. The presence of jaundice was almost exclusively associated with high-risk disease (57 of 58 patients, 98%). Cyst size >3.0 cm, solid component/mural nodule, pain symptoms, and weight loss were significantly associated with high-risk disease. C-indices were 0.82 and 0.81 on training and independent validation sets, respectively; Brier scores were 0.173 and 0.175, respectively. CONCLUSIONS: For patients with suspected IPMNs, we present an independently validated model for the prediction of high-risk disease.

Multi-institutional Validation Study of Pancreatic Cyst Fluid Protein Analysis for Prediction of High-risk Intraductal Papillary Mucinous Neoplasms of the Pancreas.

OBJECTIVE: Preliminary work by our group suggested that proteins within the pancreatic cyst fluid (CF) may discriminate degree of IPMN dysplasia. We sought to externally validate these markers and determine whether their inclusion in a preoperative clinical nomogram could increase diagnostic accuracy. SUMMARY BACKGROUND DATA: IPMN is the most common radiographically identifiable precursor to pancreatic cancer; however, the timing and frequency of its malignant progression are unknown, and there are currently no reliable preoperative tests that can determine the grade of dysplasia in IPMN. METHODS: Clinical and radiographic data, as well as CF samples, were obtained from 149 patients who underwent resection for IPMN at 1 of 3 institutions. High-risk disease was defined as the presence of high-grade dysplasia or invasive carcinoma. Multianalyte bead array analysis (Luminex) of CF was performed for 4 protein markers that were previously associated with high-risk disease. Logistic regression models were fit on training data, with and without adjustment for a previously developed clinical nomogram and validated with an external testing set. The models incorporating clinical risk score were presented graphically as nomograms. RESULTS: Within the group of 149 resected patients, 89 (60%) had low-risk disease, and 60 (40%) had high-risk disease. All 4 CF markers (MMP9, CA72-4, sFASL, and IL-4) were overexpressed in patients with high-risk IPMN (P < 0.05). Two predictive models based on preselected combinations of CF markers had concordance indices of 0.76 (Model-1) and 0.80 (Model-2). Integration of each CF marker model into a previously described clinical nomogram leads to increased discrimination compared with either the CF models or nomogram alone (c-indices of 0.84 and 0.83, respectively). CONCLUSIONS: This multi-institutional study validated 2 CF protein marker models for preoperative identification of high-risk IPMN. When combined with a clinical nomogram, the ability to predict high-grade dysplasia was even stronger.

Survival Prediction in Pancreatic Ductal Adenocarcinoma by Quantitative Computed Tomography Image Analysis.

BACKGROUND: Pancreatic cancer is a highly lethal cancer with no established a priori markers of survival. Existing nomograms rely mainly on post-resection data and are of limited utility in directing surgical management. This study investigated the use of quantitative computed tomography (CT) features to preoperatively assess survival for pancreatic ductal adenocarcinoma (PDAC) patients. METHODS: A prospectively maintained database identified consecutive chemotherapy-naive patients with CT angiography and resected PDAC between 2009 and 2012. Variation in CT enhancement patterns was extracted from the tumor region using texture analysis, a quantitative image analysis tool previously described in the literature. Two continuous survival models were constructed, with 70% of the data (training set) using Cox regression, first based only on preoperative serum cancer antigen (CA) 19-9 levels and image features (model A), and then on CA19-9, image features, and the Brennan score (composite pathology score; model B). The remaining 30% of the data (test set) were reserved for independent validation. RESULTS: A total of 161 patients were included in the analysis. Training and test sets contained 113 and 48 patients, respectively. Quantitative image features combined with CA19-9 achieved a c-index of 0.69 [integrated Brier score (IBS) 0.224] on the test data, while combining CA19-9, imaging, and the Brennan score achieved a c-index of 0.74 (IBS 0.200) on the test data. CONCLUSION: We present two continuous survival prediction models for resected PDAC patients. Quantitative analysis of CT texture features is associated with overall survival. Further work includes applying the model to an external dataset to increase the sample size for training and to determine its applicability.

Progression Patterns in the Remnant Pancreas after Resection of Non-Invasive or Micro-Invasive Intraductal Papillary Mucinous Neoplasms (IPMN).

BACKGROUND: Although IPMN are thought to represent a whole-gland disease, segmental resection remains the most frequently performed treatment. We sought to determine the rates, patterns, and predictors of IPMN progression in the pancreatic remnant following segmental resection of noninvasive or microinvasive IPMN. METHODS: A prospectively maintained database was queried to identify all patients who underwent resection of noninvasive or microinvasive IPMN (≤ 10 mm of invasive component) between 1989 and 2015. Progression (recurrence) was defined as either the development of cancer, a new IPMN cystic lesion > 1 cm or ≥ 50% increase in the diameter of residual IPMN lesions in the remnant. Univariate and multivariate cox regression models were created to determine predictors of progression. RESULTS: A total of 319 patients underwent resection for noninvasive and microinvasive IPMN. The median age was 68, 53% had branch-duct (BD) IPMN, and 6% had microinvasive disease. After a median follow-up of 42 months, 71 patients (22%) experienced IPMN progression. Within this group of 71 patients, 11 (16% of recurrence) developed invasive cancer in the pancreatic remnant after a median of 28 months. Twelve patients (17%) experienced progression > 5 years following initial resection. On multivariate analysis, a distal location of the initial lesion was associated with an increased risk of progression (multivariate hazards ratio = 2.43, confidence interval 1.47-4.0, p < 0.001). CONCLUSIONS: In this study, 22% of patients had disease progression following resection of noninvasive or microinvasive IPMN; 16% of these progressions represented invasive disease. These patients represent a high-risk group and should undergo long-term radiographic surveillance.

Should Patients With Cystic Lesions of the Pancreas Undergo Long-term Radiographic Surveillance?: Results of 3024 Patients Evaluated at a Single Institution.

OBJECTIVE: In 2015, the American Gastroenterological Association recommended the discontinuation of radiographic surveillance after 5 years for patients with stable pancreatic cysts. The current study evaluated the yield of continued surveillance of pancreatic cysts up to and after 5 years of follow up. METHODS: A prospectively maintained registry of patients evaluated for pancreatic cysts was queried (1995-2016). Patients who initially underwent radiographic surveillance were divided into those with <5 years and ≥5 years of follow up. Analyses for the presence of cyst growth (>5 mm increase in diameter), cross-over to resection, and development of carcinoma were performed. RESULTS: A total of 3024 patients were identified, with 2472 (82%) undergoing initial surveillance. The ≥5 year group (n = 596) experienced a greater frequency of cyst growth (44% vs. 20%; P < 0.0001), a lower rate of cross-over to resection (8% vs 11%; P = 0.02), and a similar frequency of progression to carcinoma (2% vs 3%; P = 0.07) compared with the <5 year group (n = 1876). Within the ≥5 year group, 412 patients (69%) had demonstrated radiographic stability at the 5-year time point. This subgroup, when compared with the <5 year group, experienced similar rates of cyst growth (19% vs. 20%; P= 0.95) and lower rates of cross-over to resection (5% vs 11%; P< 0.0001) and development of carcinoma (1% vs 3%; P= 0.008). The observed rate of developing cancer in the group that was stable at the 5-year time point was 31.3 per 100,000 per year, whereas the expected national age-adjusted incidence rate for this same group was 7.04 per 100,000 per year. CONCLUSION: Cyst size stability at the 5-year time point did not preclude future growth, cross-over to resection, or carcinoma development. Patients who were stable at 5 years had a nearly 3-fold higher risk of developing cancer compared with the general population and should continue long-term surveillance.

Patterns of Failure in Patients With Borderline Resectable/Locally Advanced Pancreatic Cancer After Preoperative Chemotherapy and Stereotactic Body Radiation Therapy.

Purpose: The role of preoperative stereotactic body radiation therapy (SBRT) in pancreatic cancer is controversial, and questions regarding the optimal dose and radiation treatment field remain. To better inform future investigations of SBRT dose and radiation fields, we evaluated the patterns of failure in patients with borderline resectable/locally advanced pancreatic cancer (BR/LAPC) after preoperative chemotherapy and SBRT in patients who underwent surgical resection. Methods and Materials: We performed a single-institution retrospective review of consecutive patients treated from September 2017 to January 2022 with BR/LAPC. Patients who underwent preoperative chemotherapy and SBRT followed by surgical resection were reviewed. SBRT was delivered to a dose of 33 Gy in 5 fractions. Kaplan-Meier overall survival and progression-free survival estimates were calculated. Results: In total, 18 patients (12 BRPC, 6 LAPC) were included. Median age was 69 years (range 41-84 years). Median follow-up was 30 months (range 13-59 months). Seventeen patients (94%) had a R0 resection and 13 (72%) underwent vascular reconstruction. Median overall survival and progression-free survival was 42 months (range 13-59 months) and 23 months (range 1-45 months), respectively. In total, 61% (11/18) patients experienced progression at any point during follow-up. Of the patients who experienced recurrence, 27% (3/11) experienced local progression as component of their first recurrence, whereas 100% (11/11) experienced distant progression as a component of their first recurrence. When examining all recurrences that occurred at any point in follow-up, 28% (5/18) of patients experienced local or locoregional recurrence and 61% (11/18) experienced distant progression. Conclusions: Local control and margin negative resection rates were excellent with preoperative chemotherapy and nondose-escalated SBRT in surgically resected patients with BR/LAPC. Distant recurrence was the predominant site of failure with lower incidences of isolated locoregional recurrences. Additional research is needed to determine the ideal treatment volume and patients who may benefit from dose escalation.

Defining MRI Superiority over CT for Colorectal and Neuroendocrine Liver Metastases.

BACKGROUND: We compared CT and MRI for staging metastatic colorectal or neuroendocrine liver metastases (CRLMs and NELMs, respectively) to assess their impact on tumor burden. METHODS: A prospectively maintained database was queried for patients who underwent both imaging modalities within 3 months, with two blinded radiologists (R1 and R2) independently assessing the images for liver lesions. To minimize recall bias, studies were grouped by modality, and were randomized and evaluated separately. RESULTS: Our query yielded 76 patients (42 CRLMs; 34 NELMs) with low interrater variability (intraclass correlation coefficients: CT = 0.941, MRI = 0.975). For CRLMs, there were no significant differences in lesion number or size between CT and MRI. However, in NELMs, Eovist®-enhanced MRI detected more lesions (R1: 14.3 vs. 12.1, p = 0.02; R2: 14.4 vs. 12.4, p = 0.01) and smaller lesions (R1: 5.7 vs. 4.4, p = 0.03; R2: 4.8 vs. 2.9, p = 0.02) than CT. CONCLUSIONS: CT and MRI are equivalent for CRLMs, but for NELMs, MRI outperforms CT in detecting more and smaller lesions, potentially influencing treatment planning and surgery.

Multimodal radiomics and cyst fluid inflammatory markers model to predict preoperative risk in intraductal papillary mucinous neoplasms.

Purpose: Our paper contributes to the burgeoning field of surgical data science. Specifically, multimodal integration of relevant patient data is used to determine who should undergo a complex pancreatic resection. Intraductal papillary mucinous neoplasms (IPMNs) represent cystic precursor lesions of pancreatic cancer with varying risk for malignancy. We combine previously defined individual models of radiomic analysis of diagnostic computed tomography (CT) with protein markers extracted from the cyst fluid to create a unified prediction model to identify high-risk IPMNs. Patients with high-risk IPMN would be sent for resection, whereas patients with low-risk cystic lesions would be spared an invasive procedure. Approach: Retrospective analysis of prospectively acquired cyst fluid and CT scans was undertaken for this study. A predictive model combining clinical features with a cyst fluid inflammatory marker (CFIM) was applied to patient data. Quantitative imaging (QI) features describing radiomic patterns predictive of risk were extracted from scans. The CFIM model and QI model were combined into a single predictive model. An additional model was created with tumor-associated neutrophils (TANs) assessed by a pathologist at the time of resection. Results: Thirty-three patients were analyzed (7 high risk and 26 low risk). The CFIM model yielded an area under the curve (AUC) of 0.74. Adding the QI model improved performance with an AUC of 0.88. Combining the CFIM, QI, and TAN models further increased performance to an AUC of 0.98. Conclusions: Quantitative analysis of routinely acquired CT scans combined with CFIMs provides accurate prediction of risk of pancreatic cancer progression. Although a larger cohort is needed for validation, this model represents a promising tool for preoperative assessment of IPMN.

A unifying paradigm for transcriptional heterogeneity and squamous features in pancreatic ductal adenocarcinoma.

Pancreatic cancer expression profiles largely reflect a classical or basal-like phenotype. The extent to which these profiles vary within a patient is unknown. We integrated evolutionary analysis and expression profiling in multiregion-sampled metastatic pancreatic cancers, finding that squamous features are the histologic correlate of an RNA-seq-defined basal-like subtype. In patients with coexisting basal and squamous and classical and glandular morphology, phylogenetic studies revealed that squamous morphology represented a subclonal population in an otherwise classical and glandular tumor. Cancers with squamous features were significantly more likely to have clonal mutations in chromatin modifiers, intercellular heterogeneity for MYC amplification and entosis. These data provide a unifying paradigm for integrating basal-type expression profiles, squamous histology and somatic mutations in chromatin modifier genes in the context of clonal evolution of pancreatic cancer.

The Evolutionary Origins of Recurrent Pancreatic Cancer.

Surgery is the only curative option for stage I/II pancreatic cancer; nonetheless, most patients will experience a recurrence after surgery and die of their disease. To identify novel opportunities for management of recurrent pancreatic cancer, we performed whole-exome or targeted sequencing of 10 resected primary cancers and matched intrapancreatic recurrences or distant metastases. We identified that recurrent disease after adjuvant or first-line platinum therapy corresponds to an increased mutational burden. Recurrent disease is enriched for genetic alterations predicted to activate MAPK/ERK and PI3K-AKT signaling and develops from a monophyletic or polyphyletic origin. Treatment-induced genetic bottlenecks lead to a modified genetic landscape and subclonal heterogeneity for driver gene alterations in part due to intermetastatic seeding. In 1 patient what was believed to be recurrent disease was an independent (second) primary tumor. These findings suggest routine post-treatment sampling may have value in the management of recurrent pancreatic cancer. SIGNIFICANCE: The biological features or clinical vulnerabilities of recurrent pancreatic cancer after pancreaticoduodenectomy are unknown. Using whole-exome sequencing we find that recurrent disease has a distinct genomic landscape, intermetastatic genetic heterogeneity, diverse clonal origins, and higher mutational burden than found for treatment-naïve disease.See related commentary by Bednar and Pasca di Magliano, p. 762.This article is highlighted in the In This Issue feature, p. 747.

Quality control in microarray assessment of gene expression in human airway epithelium.

BACKGROUND: Microarray technology provides a powerful tool for defining gene expression profiles of airway epithelium that lend insight into the pathogenesis of human airway disorders. The focus of this study was to establish rigorous quality control parameters to ensure that microarray assessment of the airway epithelium is not confounded by experimental artifact. Samples (total n = 223) of trachea, large and small airway epithelium were collected by fiberoptic bronchoscopy of 144 individuals and hybridized to Affymetrix microarrays. The pre- and post-chip quality control (QC) criteria established, included: (1) RNA quality, assessed by RNA Integrity Number (RIN) > or = 7.0; (2) cRNA transcript integrity, assessed by signal intensity ratio of GAPDH 3' to 5' probe sets < or = 3.0; and (3) the multi-chip normalization scaling factor < or = 10.0. RESULTS: Of the 223 samples, all three criteria were assessed in 191; of these 184 (96.3%) passed all three criteria. For the remaining 32 samples, the RIN was not available, and only the other two criteria were used; of these 29 (90.6%) passed these two criteria. Correlation coefficients for pairwise comparisons of expression levels for 100 maintenance genes in which at least one array failed the QC criteria (average Pearson r = 0.90 +/- 0.04) were significantly lower (p < 0.0001) than correlation coefficients for pairwise comparisons between arrays that passed the QC criteria (average Pearson r = 0.97 +/- 0.01). Inter-array variability was significantly decreased (p < 0.0001) among samples passing the QC criteria compared with samples failing the QC criteria. CONCLUSION: Based on the aberrant maintenance gene data generated from samples failing the established QC criteria, we propose that the QC criteria outlined in this study can accurately distinguish high quality from low quality data, and can be used to delete poor quality microarray samples before proceeding to higher-order biological analyses and interpretation.

CT radiomics associations with genotype and stromal content in pancreatic ductal adenocarcinoma.

PURPOSE: The aim of this study was to investigate the relationship between CT imaging phenotypes and genetic and biological characteristics in pancreatic ductal adenocarcinoma (PDAC). METHODS: In this retrospective study, consecutive patients between April 2015 and June 2016 who underwent PDAC resection were included if previously consented to a targeted sequencing protocol. Mutation status of known PDAC driver genes (KRAS, TP53, CDKN2A, and SMAD4) in the primary tumor was determined by targeted DNA sequencing and results were validated by immunohistochemistry (IHC). Radiomic features of the tumor were extracted from the preoperative CT scan and used to predict genotype and stromal content. RESULTS: The cohort for analysis consisted of 35 patients. Genomic and IHC analysis revealed alterations in KRAS in 34 (97%) patients, and changes in expression of CDKN2A in 29 (83%), SMAD4 in 16 (46%), and in TP53 in 29 (83%) patients. Models created from radiomic features demonstrated associations with SMAD4 status and the number of genes altered. The number of genes altered was the only significant predictor of overall survival (p = 0.016). By linear regression analysis, a prediction model for stromal content achieved an R2 value of 0.731 with a root mean square error of 19.5. CONCLUSIONS: In this study, we demonstrate that in PDAC SMAD4 status and tumor stromal content can be predicted using radiomic analysis of preoperative CT imaging. These data show an association between resectable PDAC imaging features and underlying tumor biology and their potential for future precision medicine.

Minimal functional driver gene heterogeneity among untreated metastases.

Metastases are responsible for the majority of cancer-related deaths. Although genomic heterogeneity within primary tumors is associated with relapse, heterogeneity among treatment-naïve metastases has not been comprehensively assessed. We analyzed sequencing data for 76 untreated metastases from 20 patients and inferred cancer phylogenies for breast, colorectal, endometrial, gastric, lung, melanoma, pancreatic, and prostate cancers. We found that within individual patients, a large majority of driver gene mutations are common to all metastases. Further analysis revealed that the driver gene mutations that were not shared by all metastases are unlikely to have functional consequences. A mathematical model of tumor evolution and metastasis formation provides an explanation for the observed driver gene homogeneity. Thus, single biopsies capture most of the functionally important mutations in metastases and therefore provide essential information for therapeutic decision-making.

Intraductal Papillary Mucinous Neoplasm of the Pancreas in Young Patients: Tumor Biology, Clinical Features, and Survival Outcomes.

AIM: The aim of this paper is to describe the characteristics of intraductal papillary mucinous neoplasms (IPMNs) of the pancreas in young patients. METHODS: We evaluated 1693 patients from the Pancreatic Surgery Consortium who underwent resection for IPMN and classified them as younger or older than 50 years of age at the time of surgery. We assessed the relationship of age with clinical, radiological, pathological, and prognostic features. RESULTS: We identified 90 (5%) young patients. Age was not associated with differences in main pancreatic duct size (P = 0.323), presence of solid components (P = 0.805), or cyst size (P = 0.135). IPMNs from young patients were less likely to be of gastric type (37 vs. 57%, P = 0.005), and more likely to be of oncocytic (15 vs. 4%, P = 0.003) and intestinal types (44 vs. 26%, P = 0.004). Invasive carcinomas arising from IPMN were less common in young patients (17 vs. 27%, P = 0.044), and when present they were commonly of colloid type (47 vs. 31% in older patients, P = 0.261) and had better overall survival than older patients (5-year, 71 vs. 37%, log-rank P = 0.031). CONCLUSION: Resection for IPMN is infrequent in young patients, but when they are resected, IPMNs from young patients demonstrate different epithelial subtypes from those in older patients and more favorable prognosis.

An unusual genomic variant of pancreatic ductal adenocarcinoma with an indolent clinical course.

We describe an 85-yr-old male of Ashkenazi Jewish descent with biopsy-proven locally advanced pancreatic ductal adenocarcinoma (PDA). The patient underwent a modified course of gemcitabine and stereotactic body radiation therapy and survived for 42 mo with a stable pancreatic head mass and no evidence of metastatic disease before death due to complications from a stroke. Whole-exome sequencing of his tumor revealed a simple genome landscape with no evidence of mutations, copy-number changes, or structural alterations in genes most commonly associated with PDA (i.e., KRAS, CDKN2A, TP53, or SMAD4). An analysis of his germline DNA revealed no pathogenic variants of significance. Whole-exome and whole-genome sequencing identified a somatic mutation of RNF213 and an inversion/deletion of CTNNA2 as the genetic basis of his PDA. Although PDA is classically characterized by a predictable set of mutations, these data suggest that alternate genetic paths to PDA may exist, which can be associated with a more indolent clinical course.

Local recurrences at the anastomotic area are clonally related to the primary tumor in sporadic colorectal carcinoma.

PURPOSE: Anastomotic recurrences (AR) occur in 2-10% of colorectal carcinoma cases after resection of primary tumor (PT). Currently, there are no molecular data investigating their genetic profile and multiple theories exist about their pathogenesis. The aim of our study was to compare the genomic profile of AR to that of the patients' corresponding matched PT and, when available, to a distant metastasis (DM). EXPERIMENTAL DESIGN: Thirty-six tumors from 14 patients were genotyped using a capture-based, next-generation assay to define the mutational status of 341 cancer-associated genes. All patients had R0 resection of their PT and AR occurred 1.1-7.0 years following PT resection. A DM or a second AR was analyzed in 8 patients. All tumors were microsatellite stable except in one patient with Lynch syndrome. RESULTS: A total of 254 somatic mutations were detected including 138 mutations in the microsatellite stable (MSS) cases. The most commonly mutated genes were APC, KRAS, TP53, PIK3CA, ATM and PIK3R1. In all patients with MSS tumors the AR and PT shared between 50-100% of mutations, including mutations in key driver genes, consistent with these tumors being clonally related. Genetic events private to DM were not detected in AR and phylogenetic analysis showed that ARs were more closely related to PT than DM. In the Lynch syndrome patient the PT and AR showed distinct somatic mutations consistent with independent primaries. CONCLUSIONS: ARs are clonally related to PT in sporadic colorectal carcinomas and do not appear to represent seeding of the anastomotic site by distant metastases.