Predictors and Diagnostic Strategies for Early-Stage Pancreatic Ductal Adenocarcinoma: A Retrospective Study

Distinct clinical outcomes and biological features of specific KRAS mutants in human pancreatic cancer

KRAS mutations in pancreatic ductal adenocarcinoma (PDAC) are suggested to vary in oncogenicity but the implications for human patients have not been explored in depth. We examined 1,360 consecutive PDAC patients undergoing surgical resection and find that KRASG12R mutations are enriched in early-stage (stage I) disease, owing not to smaller tumor size but increased node-negativity. KRASG12R tumors are associated with decreased distant recurrence and improved survival as compared to KRASG12D. To understand the biological underpinnings, we performed spatial profiling of 20 patients and bulk RNA-sequencing of 100 tumors, finding enhanced oncogenic signaling and epithelial-mesenchymal transition (EMT) in KRASG12D and increased nuclear factor κB (NF-κB) signaling in KRASG12R tumors. Orthogonal studies of mouse KrasG12R PDAC organoids show decreased migration and improved survival in orthotopic models. KRAS alterations in PDAC are thus associated with distinct presentation, clinical outcomes, and biological behavior, highlighting the prognostic value of mutational analysis and the importance of articulating mutation-specific PDAC biology.

Diagnostic Ability and Safety of Repeated Pancreatic Juice Cytology Using an Endoscopic Nasopancreatic Drainage Catheter for Pancreatic Ductal Adenocarcinoma: A Multicenter Prospective Study

Pathological examination is essential for the diagnosis and treatment of pancreatic ductal adenocarcinoma (PDAC). Moreover, a reliable pathological diagnosis is extremely important for improving prognosis, especially in early-stage PDAC. This study prospectively evaluated the usefulness of repeated pancreatic juice cytology (PJC) using an endoscopic nasopancreatic drainage (ENPD) catheter for the diagnosis of PDAC. We enrolled 82 patients suspected of having resectable PDAC, based on imaging studies, and judged the necessity for cytology. The diagnostic yield of up to six repeated PJCs and the incidence of complications, such as pancreatitis, was evaluated. A total of 60 patients were diagnosed with PDAC. The overall sensitivity and specificity were 46.7% and 95.5%, respectively. The cumulative positivity rate increased with the number of sampling sessions, reaching 58.3% in the sixth session. The sensitivity was significantly higher in the pancreatic head than in the pancreatic tail (p = 0.043). Additionally, it was 100% in four patients with a tumor size ≤10 mm. Pancreatitis occurred in six patients (7.3%), all of whom were treated conservatively. In the diagnosis of PDAC, repeated PJC using an ENPD catheter revealed a cumulative effect of sensitivity up to six times and an excellent diagnostic yield for small PDAC.

Optimal indication of endoscopic retrograde pancreatography-based cytology in the preoperative pathological diagnosis of pancreatic ductal adenocarcinoma

BACKGROUND

Endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) is extremely useful for pathological diagnosis of pancreatic ductal adenocarcinoma (PDAC); however, puncturing is difficult in some cases, and there is a risk of needle tract seeding. This study evaluated the indications for endoscopic retrograde pancreatography-based (ERP)-based cytology for the preoperative diagnosis of PDAC.

METHODS

This study included 267 patients with PDAC who underwent preoperative ERP. The diagnostic performance of ERP-based cytology for PDAC was evaluated based on the sample collection method (pancreatic juice cytology [PJC] during ERP, brush cytology, PJC via endoscopic nasopancreatic drainage [ENPD] catheter), lesion site (pancreatic head, body/tail), and lesion size (≤10 mm, 10-20 mm, >20 mm), and compared with the diagnostic performance of EUS-FNA.

RESULTS

The overall sensitivity of ERP-based cytology was 54.9%; sensitivity by the sampling method was 34.7% for PJC during ERP, 65.8% for brush cytology, and 30.8% for PJC via an ENPD catheter. The sensitivity of EUS-FNA was 85.3%. Brush cytology and PJC via an ENPD catheter were performed more often in pancreatic body/tail lesions than in head lesions (P = 0.016 and P < 0.001, respectively), and the overall sensitivity of ERP-based cytology was better for body/tail lesions (63.2% vs. 49.0%, P = 0.025). The sensitivities of ERP-based cytology and EUS-FNA in diagnosing PDAC ≤10 mm were 92.3% and 33.3%, respectively. Post-ERP pancreatitis was observed in 22 patients (8.2%) and significantly less common with ENPD catheters (P = 0.002).

CONCLUSIONS

ERP-based cytology may be considered the first choice for pathological diagnosis of PDAC ≤10 mm and in the pancreatic body/tail.

Pre-Operative Imaging and Pathological Diagnosis of Localized High-Grade Pancreatic Intra-Epithelial Neoplasia without Invasive Carcinoma

Pancreatic ductal adenocarcinoma (PDAC) arises from precursor lesions, such as pancreatic intra-epithelial neoplasia (PanIN) and intraductal papillary mucinous neoplasm (IPMN). The prognosis of high-grade precancerous lesions, including high-grade PanIN and high-grade IPMN, without invasive carcinoma is good, despite the overall poor prognosis of PDAC. High-grade PanIN, as a lesion preceding invasive PDAC, is therefore a primary target for intervention. However, detection of localized high-grade PanIN is difficult when using standard radiological approaches. Therefore, most studies of high-grade PanIN have been conducted using specimens that harbor invasive PDAC. Recently, imaging characteristics of high-grade PanIN have been revealed. Obstruction of the pancreatic duct due to high-grade PanIN may induce a loss of acinar cells replaced by fibrosis and lobular parenchymal atrophy. These changes and additional inflammation around the branch pancreatic ducts (BPDs) result in main pancreatic duct (MPD) stenosis, dilation, retention cysts (BPD dilation), focal pancreatic parenchymal atrophy, and/or hypoechoic changes around the MPD. These indirect imaging findings have become important clues for localized, high-grade PanIN detection. To obtain pre-operative histopathological confirmation of suspected cases, serial pancreatic-juice aspiration cytologic examination is effective. In this review, we outline current knowledge on imaging characteristics of high-grade PanIN.

Clinical Analysis of Early-Stage Pancreatic Cancer and Proposal for a New Diagnostic Algorithm: A Multicenter Observational Study

Early diagnosis of pancreatic ductal adenocarcinoma (PDAC) is challenging but essential for improving its poor prognosis. We established a multicenter study to clarify the clinicopathological features, and to propose new algorithm for early diagnosis of PDAC. Ninety-six patients with stage 0 and IA PDAC were enrolled from 13 high-volume centers. Overall, 70% of the patients were asymptomatic. The serum pancreatic enzyme levels were abnormal in half of the patients. The sensitivity of endoscopic ultrasonography (EUS) for detecting small PDAC was superior to computed tomography and magnetic resonance imaging (MRI) (82%, 58%, and 38%, respectively). Indirect imaging findings were useful to detect early-stage PDAC; especially, main pancreatic duct stenosis on MRI had the highest positive rate of 86% in stage 0 patients. For preoperative pathological diagnosis, the sensitivity of endoscopic retrograde cholangiopancreatography (ERCP)-associated pancreatic juice cytology was 84%. Among the stage IA patients, EUS-guided fine-needle aspiration revealed adenocarcinoma in 93% patients. For early diagnosis of PDAC, it is essential to identify asymptomatic patients and ensure close examinations of indirect imaging findings and standardization of preoperative pathological diagnosis. Therefore, a new diagnostic algorithm based on tumor size and imaging findings should be developed.

Role of Endoscopic Ultrasonography and Endoscopic Retrograde Cholangiopancreatography in the Diagnosis of Pancreatic Cancer

Pancreatic cancer has the poorest prognosis among all cancers, and early diagnosis is essential for improving the prognosis. Along with radiologic modalities, such as computed tomography (CT) and magnetic resonance imaging (MRI), endoscopic modalities play an important role in the diagnosis of pancreatic cancer. This review evaluates the roles of two of those modalities, endoscopic ultrasonography (EUS) and endoscopic retrograde cholangiopancreatography (ERCP), in the diagnosis of pancreatic cancer. EUS can detect pancreatic cancer with higher sensitivity and has excellent sensitivity for the diagnosis of small pancreatic cancer that cannot be detected by other imaging modalities. EUS may be useful for the surveillance of pancreatic cancer in high-risk individuals. Contrast-enhanced EUS and EUS elastography are also useful for differentiating solid pancreatic tumors. In addition, EUS-guided fine needle aspiration shows excellent sensitivity and specificity, even for small pancreatic cancer, and is an essential examination method for the definitive pathological diagnosis and treatment decision strategy. On the other hand, ERCP is invasive and performed less frequently for the purpose of diagnosing pancreatic cancer. However, ERCP is essential in cases that require evaluation of pancreatic duct stricture that may be early pancreatic cancer or those that require differentiation from focal autoimmune pancreatitis.

Efficacy of the physiobiological parameter-based grading system for predicting the long-term prognosis after curative surgery for resectable pancreatic cancer

BACKGROUND

Several prognostic scoring systems based on cancer-related inflammation have been developed. We aimed to evaluate the efficacy of a novel physiobiological parameter-based grading system (PGS) for predicting the long-term prognosis after curative-intent surgery for pancreatic ductal adenocarcinoma.

METHODS

One-hundred fifty-nine consecutive patients with pancreatic ductal adenocarcinoma were enrolled. Univariate and multivariate analyses were performed to identify variables associated with overall survival and recurrence-free survival. Patients were stratified according to the PGS score with a cut-off value of 40.5 being estimated by receiver-operating characteristic curve analysis. Propensity score matching analysis (PSM) was performed to compare between patients with low and high scores in the physiobiological parameter-based grading system.

RESULTS

Univariate analysis showed that CEA elevation (p = 0.032), tumor size ≥20 mm (p < 0.001), lymph node metastasis (p < 0.001), high-PGS (p < 0.001), CA19-9 elevation (p < 0.001), Prognostic nutritious index (PNI) ≤40 (p = 0.002) and positive Glasgow prognostic score (GPS) (p = 0.001) were risk factors for poor overall survival. CEA elevation (p = 0.006), Tumor size ≥20 mm (p < 0.001), lymph node metastasis (p < 0.001), high-PGS (p < 0.001), CA19-9 elevation (p < 0.001), PNI ≤40 (p = 0.017) and positive GPS (p < 0.001) were identified as risk factors for poor recurrence-free survival. The multivariate analysis revealed that tumor size ≥20 mm (p = 0.007, p = 0.008, respectively) and high PGS score (p = 0.041, p = 0.018, respectively) were independently associated with poor overall survival and recurrence-free survival. Patients with high-PGS showed a significantly worse long-term prognosis even after PSM.

CONCLUSION

The PGS is a novel nomogram that could effectively predict long-term outcomes following curative surgery in patients with pancreatic ductal adenocarcinoma.

Radiomics in stratification of pancreatic cystic lesions: Machine learning in action

Pancreatic cystic lesions (PCLs) are well-known precursors of pancreatic cancer. Their diagnosis can be challenging as their behavior varies from benign to malignant disease. Precise and timely management of malignant pancreatic cysts might prevent transformation to pancreatic cancer. However, the current consensus guidelines, which rely on standard imaging features to predict cyst malignancy potential, are conflicting and unclear. This has led to an increased interest in radiomics, a high-throughput extraction of comprehensible data from standard of care images. Radiomics can be used as a diagnostic and prognostic tool in personalized medicine. It utilizes quantitative image analysis to extract features in conjunction with machine learning and artificial intelligence (AI) methods like support vector machines, random forest, and convolutional neural network for feature selection and classification. Selected features can then serve as imaging biomarkers to predict high-risk PCLs. Radiomics studies conducted heretofore on PCLs have shown promising results. This cost-effective approach would help us to differentiate benign PCLs from malignant ones and potentially guide clinical decision-making leading to better utilization of healthcare resources. In this review, we discuss the process of radiomics, its myriad applications such as diagnosis, prognosis, and prediction of therapy response. We also discuss the outcomes of studies involving radiomic analysis of PCLs and pancreatic cancer, and challenges associated with this novel field along with possible solutions. Although these studies highlight the potential benefit of radiomics in the prevention and optimal treatment of pancreatic cancer, further studies are warranted before incorporating radiomics into the clinical decision support system.

Pancreatic Juice Exosomal MicroRNAs as Biomarkers for Detection of Pancreatic Ductal Adenocarcinoma

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is a lethal neoplasm because of difficulties in early detection. Several studies have recently suggested that exosomes may have potential as novel biomarkers. This study aimed to isolate exosomes from pancreatic juice and to investigate whether exosomal microRNAs (ex-miRs) could be used as biomarkers for PDAC.

METHODS

Pancreatic juice was collected from patients with PDAC and chronic pancreatitis (CP) by endoscopic retrograde pancreatography. Exosomes were extracted by ultracentrifugation. The presence of exosomes was confirmed by electron microscopy and Western blotting using anti-CD63, -CD81, and -TSG101 antibodies. Relative levels of ex-miR-21 and ex-miR-155 were quantified and compared between PDAC and CP patients.

RESULTS

A total of 35 pancreatic juice samples (27 PDAC and 8 CP) were collected. Relative levels of both ex-miR-21 and ex-miR-155 were significantly higher in PDAC patients compared with CP patients (p < 0.001 and p = 0.008, respectively). By contrast, no significant difference was apparent in relative levels of miR-21 and miR-155 in whole pancreatic juice from PDAC patients compared with CP patients (p = 0.08 and p = 0.61, respectively). Ex-miR-21 and ex-miR-155 levels discriminated PDAC patients from CP patients with area under the curve values of 0.90 and 0.89, respectively. The accuracies of ex-miR-21 levels, ex-miR-155 levels, and pancreatic juice cytology were 83%, 89%, and 74%, respectively. When combining the results of ex-miR profiling with pancreatic juice cytology, the accuracy was improved to 91%.

CONCLUSIONS

We successfully extracted exosomes from pancreatic juice. Ex-miRs, including ex-miR-21 and ex-miR-155, in pancreatic juice may be developed as biomarkers for PDAC.

Significance of neoadjuvant chemoradiotherapy for borderline resectable pancreatic head cancer: Pathological local invasion and microvessel invasion analysis

Borderline resectable pancreatic head cancer (BR-PHC) has low resectability due to vascular invasion. Although the clinical effects of neoadjuvant chemoradiotherapy (NAC-RT) for BR-PHC have been examined, few studies have reported its pathological aspects. The present study retrospectively investigated the effect of NAC-RT on the histological features of BR-PHC. A total of 29 patients with BR-PHC who underwent NAC-RT, and 55 controls with resectable PHC, who underwent pancreaticoduodenectomy at the Kurume University Hospital. Tumor staging, lymphovascular invasion (LVI), and microvessel invasion (MVI) were evaluated. The median tumor size in the NAC-RT group was 2.0 cm, and it was smaller than that of the control group (P=0.006). The rates of lymph node metastasis, LVI, and MVI were significantly lower in the NAC-RT group (P<0.001, 0.002, and 0.015, respectively). Overall survival in the NAC-RT group was comparable to that in the control group, although patients with BR-PHC generally had a poorer prognosis than those with resectable PHC. Patients in the NAC-RT group without portal vein invasion (PVI) had a significantly better prognosis than those with PVI in the control group (P=0.002). NAC-RT may be beneficial for patients with BR-PHC by inhibiting local invasion and metastasis as prognosis following resection could be equivalent to that of patients with conventional ductal adenocarcinoma.

Diagnosis and management of intraductal papillary mucinous neoplasms of the pancreas

Background and aim of the work: Intraductal papillary mucinous neoplasms (IPMN) of the pancreas are cystic lesions with malignant potential. Given their increasing incidence in the latest years, a precise characterization and management of these lesions have become more and more crucial: even though the majority of IPMN has a benign and indolent course, it is fundamental to early recognize and stratify patients in order to accurately plan a tailored follow-up and to individuate those that would benefit of surgical treatment. The aim of this paper is to highlight the most recent evidence on IPMN available in the current literature. Methods: We performed a review of the recent literature and of the recent guidelines about pancreatic cystic lesions, especially IPMN. Results: The incidence of IPMN is now on the rise: an increasing number of patients, possibly because of the increasing diagnostic yield of imaging techniques, is being diagnosed with pancreatic cystic lesions, a great part of which are IPMN. The possibility of malignant transformation requires a careful approach to these patients, in the need of tailoring the follow-up and the therapy. Conclusion: A detailed diagnosis, the determination of risk factors for malignant transformation and a multisciplinary approach are of foremost importance for an effective management of IPMN. (www.actabiomedica.it)

Genetic assessment of recurrent pancreatic high-risk lesions in the remnant pancreas: Metachronous multifocal lesion or local recurrence?

BACKGROUND

It is difficult to determine whether a second high-risk lesion, including pancreatic ductal adenocarcinoma or high-grade pancreatic intraepithelial neoplasm, is a metachronous multifocal lesion or represents local recurrence after resection of the first high-risk lesion. This study attempts to clarify the characteristics of second high-risk lesions in the remnant pancreas using genetic analyses.

METHODS

Clinicopathologic data were collected from 12 patients who underwent pancreatectomy for a second high-risk lesion in the remnant pancreas. We performed mutational and immunohistochemical analyses of 4 major genes-KRAS, TP53, CDKN2A, and SMAD4-associated with pancreatic ductal adenocarcinoma progression, as well as targeted next-generation sequencing.

RESULTS

Mutations in the four genes in the second high-risk lesion were consistent with the first lesion in four patients but were inconsistent in the remaining eight patients, and thus we considered that the latter eight patients likely had metachronous multifocal high-risk lesions and the other four patients had local recurrence. The estimated cumulative recurrence rate after resection of the second high-risk lesion was greater in the local recurrence group compared with the metachronous multifocal group, and the estimated cumulative disease-specific survival rate was greater in the metachronous multifocal group. Targeted next-generation sequencing demonstrated that the second lesions in the metachronous multifocal high-risk lesion group showed differences in founder mutations compared with the first lesion. In the local recurrence group, the founder mutations in the second lesion were common with those in the first lesion.

CONCLUSION

Genetic assessment might help discriminate metachronous multifocal high-risk lesions from local recurrence.