Prognostic implication of extra-pancreatic organ invasion in resectable pancreas ductal adenocarcinoma in the pancreas tail

OBJECTIVES

To assess the prognostic significance of extra-pancreatic organ invasion in patients with resectable pancreatic ductal adenocarcinoma (PDAC) in the pancreas tail.

MATERIALS & METHODS

This retrospective study included patients with resectable PDAC in the pancreas tail who received upfront surgery between 2014 and 2020 at a tertiary institution. Preoperative pancreas protocol computed tomography (CT) scans evaluated tumor size, peripancreatic tumor infiltration, suspicious metastatic lymph nodes, and extra-pancreatic organ invasion. The influence of extra-pancreatic organ invasion, detected by CT or postoperative pathology, on pathologic resection margin status was evaluated using logistic regression. The impact on recurrence-free survival (RFS) was analyzed using multivariable Cox proportional hazard models (clinical-CT and clinical-pathologic).

RESULTS

The study included 158 patients (mean age, 65 years ± 8.8 standard deviation; 93 men). Extra-pancreatic organ invasion identified by either CT (p = 0.92) or pathology (p = 0.99) was not associated with a positive resection margin. Neither CT (p = 0.42) nor pathological (p = 0.64) extra-pancreatic organ invasion independently correlated with RFS. Independent predictors for RFS included suspicious metastatic lymph node (hazard ratio [HR], 2.05; 95 % confidence interval [CI], 1.08-3.9; p = 0.03) on CT in the clinical-CT model, pathological T stage (HR, 2.97; 95 % confidence interval [CI], 1.39-6.35; p = 0.005 for T2 and HR, 3.78; 95 % CI, 1.64-8.76; p = 0.002 for T3) and adjuvant therapy (HR, 0.62; 95 % confidence interval [CI], 0.42-0.92; p = 0.02) in the clinical-pathologic model.

CONCLUSION

Extra-pancreatic organ invasion does not independently influence pathologic resection margin status and RFS in patients with resectable PDAC in the pancreas tail after curative-intent resection; therefore, it should not be considered a high-risk factor.

Important Radiologic and Clinical Factors for Predicting Overall Survival in Pancreatic Adenocarcinoma Patients Who Underwent FOLFIRINOX

BACKGROUND

To predict poor overall survival (OS) in pancreatic adenocarcinoma (PAC) who underwent FOLFIRINOX (5-fluorouracil/leucovorin/irinotecan/oxaliplatin) using clinical and computed tomography (CT) findings.

METHODS

A total of 189 patients with PAC who received FOLFIRINOX were retrospectively included. Two reviewers assessed CT findings and resectability based on National Comprehensive Cancer Network guidelines. They determined tumor size changes according to Response Evaluation Criteria in Solid Tumors (RECIST 1.1). Delta measurements were performed. Clinical results, such as whether to perform surgery, were also investigated. A Cox proportional hazard model was used to identify significant predictors for OS. A CT-based nomogram was constructed to predict OS.

RESULTS

Seventy-four patients (39.2%) underwent surgery. For OS, rim enhancement of PAC on baseline CT (hazard ratio [HR], 1.75; 95% confidence interval [CI], 1.10-2.77; P = 0.018), high delta tumor on baseline CT (HR, 2.46; 95% CI, 1.55-3.91; P < 0.001), progressive disease at follow-up CT (HR, 8.89; 95% CI, 2.94-26.87; P < 0.001), and without surgery (HR, 2.81; 95% CI, 1.49-5.30; P = 0.001) were important features related to poor prognosis. The nomogram showed good predictive ability for the survival.

CONCLUSION

Both clinical and CT findings were useful for predicting OS after FOLFIRINOX in PAC.

Does CT overestimate extra-pancreatic perineural invasion in patients with pancreatic ductal adenocarcinoma following neoadjuvant chemoradiation therapy?

OBJECTIVES

To evaluate the diagnostic performance of CT in the assessment of extra-pancreatic perineural invasion (EPNI) in patients with pancreatic ductal adenocarcinoma (PDAC).

METHODS

This retrospective study included 123 patients (66 men; median age, 66 years) with PDAC who underwent radical surgery and pancreatic protocol CT for assessing surgical resectability between September 2011 and March 2019. Among the 123 patients, 97 patients had received neoadjuvant chemoradiation therapy (CRT). Two radiologists reviewed the CT images for evidence of EPNI using a 5-point scale (5 = definitely present, 4 = probably present, 3 = equivocally present, 2 = probably absent, and 1 = definitely absent). Diagnostic performance for assessing EPNI was evaluated with receiver operating characteristic (ROC) curve analysis.

RESULTS

The sensitivity, specificity, and area under the ROC curve for assessing EPNI were 98%, 30%, and 0.62 in all patients; 97%, 22%, and 0.59 in patients with neoadjuvant CRT; and 100%, 100%, and 1.00 in patients without neoadjuvant CRT, respectively. False-positive assessment of EPNI occurred in 23% of patients (n = 28/123), and 100% of these (n = 28/28) had received neoadjuvant CRT. There was moderate to substantial agreement between the readers (ĸ = 0.49-0.62).

CONCLUSION

Pancreatic protocol CT has better diagnostic performance for determination of EPNI in treatment naïve patients with PDAC and overestimation of EPNI is likely in patients who have received preoperative CRT.

ADVANCES IN KNOWLEDGE

Pancreatic protocol CT has better diagnostic performance for the detection of EPNI in treatment naïve patients compared to patients receiving neoadjuvant CRT.

Radiographic duodenal invasion is associated with poor prognosis and early recurrence in patients with pancreatic ductal adenocarcinoma

BACKGROUND

The prognostic impact of radiographic duodenal invasion (rDI) of pancreatic ductal adenocarcinoma (PDAC) has yet to be fully elucidated. This retrospective study aimed to investigate the prognostic and clinicopathological significance of rDI in patients with PDAC after pancreatoduodenectomy (PD).

MATERIALS AND METHODS

We retrospectively analyzed 223 consecutive patients with resectable (R) and borderline resectable (BR)-PDAC that underwent up-front PD between 2002 and 2018. rDI was assessed by preoperative multi-detector row computed tomography.

RESULTS

Ninety-three (42%) patients with PDAC had rDI, and all of them had pathological DI (pDI). The rDI(+) group had larger tumor size, BR-PDAC was more common, there was higher serum CA19-9 level, and microscopic lymphovascular invasion was more common than in the rDI(-) group. rDI was associated with significant reduction in overall survival (OS) (P < 0.001) and recurrence-free survival (RFS) (P < 0.001). In multivariate analysis, rDI was an independent prognostic factor in OS [hazard ratio (HR) = 0.52; 95% confidence interval (CI) 0.38-0.73, P < 0.001] and RFS [HR = 0.56; 95% CI 0.40-0.78, P = 0.001]. rDI was also an independent risk factor for early recurrence within 12 months [odds ratio (OR) = 0.36; 95% CI 0.18-0.73, P = 0.005]. rDI had positive correlation with liver recurrence (P = 0.024).

CONCLUSION

Biological aggressiveness of PDAC with rDI implies short OS and early recurrence with frequent liver metastasis. Aggressive perioperative chemotherapy is recommended to improve prognosis, especially for R-PDAC patients with rDI.

Perineural Invasion and Spread in Common Abdominopelvic Diseases: Imaging Diagnosis and Clinical Significance

Malignancies and other diseases may spread by multiple pathways, including direct extension, hematogenous spread, or via lymphatic vessels. A less-well-understood route is the peripheral nervous system, which is known as perineural spread (PNS). In addition to accounting for pain and other neurologic symptoms, PNS affects both disease prognosis and management. Although PNS is commonly discussed in relation to head and neck tumors, there is emerging data regarding PNS in abdominopelvic malignancies and other conditions such as endometriosis. Due to improved contrast and spatial resolution, perineural invasion, a finding heretofore diagnosed only at pathologic examination, can be detected at CT, MRI, and PET/CT. PNS most commonly manifests as abnormal soft-tissue attenuation extending along neural structures, and diagnosis of it is aided by optimizing imaging parameters, understanding pertinent anatomy, and becoming familiar with the typical neural pathways of spread that largely depend on the disease type and location. In the abdomen, the celiac plexus is a central structure that innervates the major abdominal organs and is the principal route of PNS in patients with pancreatic and biliary carcinomas. In the pelvis, the lumbosacral plexus and inferior hypogastric plexus are the central structures and principal routes of PNS in patients with pelvic malignancies. Although the imaging findings of PNS may be subtle, a radiologic diagnosis can have a substantial effect on patient care. Knowledge of anatomy and known routes of PNS and optimizing imaging parameters is of utmost importance in providing key information for prognosis and treatment planning. © RSNA, 2023 Supplemental material and the slide presentation from the RSNA Annual Meeting are available for this article. Quiz questions for this article are available through the Online Learning Center.

The prognostic significance of duodenal wall invasion in pancreatic adenocarcinoma

OBJECTIVE

The most recent edition of the American Joint Committee on Cancer Staging Manual (AJCC, 8th edition) relies only on tumor size for staging resectable pancreatic adenocarcinoma, and the presence of duodenal wall invasion (DWI) no longer has an impact on staging. However, very few studies have evaluated its significance. In this study, we aim to evaluate the prognostic significance of DWI in pancreatic adenocarcinoma.

METHODS

We reviewed 97 consecutive internal cases of resected pancreatic head ductal adenocarcinoma, and clinicopathologic parameters were recorded. All cases were staged according to the 8th edition of AJCC, and the patients were divided into two groups based on the presence or absence of DWI.

RESULTS

Out of our 97 cases, 53 patients had DWI (55%). In univariate analysis, DWI was significantly associated with lymphovascular invasion and lymph node metastasis (AJCC 8th edition pN stage). In univariate analysis of overall survival, age > 60, absence of DWI, and African American race were associated with worse overall survival. In multivariate analysis, age > 60, absence of DWI, and African American race were associated with worse progression-free survival and overall survival.

CONCLUSION

Although DWI is associated with lymph node metastasis, it is not associated with inferior disease-free/overall survival.

Association of CT Findings With Perineural Invasion in Gallbladder Cancer: Preliminary Assessment

Perineural invasion (PNI) indicates a worse prognosis for patients with gallbladder cancer (GBC). This preliminary retrospective study included 19 patients with GBC who under-went contrast-enhanced CT in the 4 weeks before undergoing surgical resection. GBC showed PNI on pathologic assessment in eight of 19 patients. On CT, wall thickening morphology had sensitivity of 75.0% and specificity of 81.8% for PNI; soft-tissue stranding around the celiac plexus had sensitivity of 62.5% and specificity of 100.0% for PNI.

Preoperative diagnosis of perineural invasion in patients with periampullary carcinoma by MSCT imaging: preliminary observations and clinical implications

PURPOSE

The aim of this study was to investigate the value of multi-slice computed tomography (MSCT) in preoperatively diagnosing perineural invasion (PNI) of periampullary carcinoma (PAC).

METHODS

Of 81 patients pathologically diagnosed as PAC, 73 patients were included. Their clinical documents and preoperative upper abdominal enhanced MSCT images were retrospectively reviewed to analyse clinical characteristics and MSCT features. MSCT features included tumor size, classification of fat tissue around celiac trunk and superior mesenteric artery. Chi-square test, Mann-Whitney U test or Fisher's exact test were used to compare the differences between PNI group and Non-PNI group. ROC analysis was performed to evaluate diagnostic efficiency for PAC PNI.

RESULTS

There were significant differences in some clinical characteristics and MSCT features. PAC PNI patients had significantly higher CA19-9 levels, higher CEA levels, larger tumor size and higher classification of fat tissue around celiac trunk than Non-PNI patients (All P values < 0.05). In univariate analysis, tumor size had the highest AUC as 0.806, fat tissue around celiac trunk and CEA had the highest specificity as 100% (P < 0.001). In multivariate analysis, classification of fat tissue around celiac trunk incorporated with tumor size, CA19-9, CEA, age and sex, showed the highest AUC as 0.939, with specificity of 95.0% and sensitivity of 90.4% (P < 0.001).

CONCLUSION

PAC PNI could be diagnosed preoperatively by evaluating abdominal enhanced MSCT images with high accuracy, combined with serum tumor marker could be more helpful.

Predictive factors for early recurrence after pancreaticoduodenectomy in patients with resectable pancreatic head cancer: A multicenter retrospective study

BACKGROUND

Patients diagnosed with resectable pancreatic ductal adenocarcinoma often experience early recurrence even after upfront R0 resection. This study aimed to define early recurrence and identify preoperative risk factors for early recurrence after upfront pancreaticoduodenectomy in patients with resectable pancreatic ductal adenocarcinoma of the pancreatic head.

METHODS

This multicenter, retrospective study involved 500 patients who underwent pancreaticoduodenectomy resectable pancreatic ductal adenocarcinoma of the pancreatic head at 10 institutions between 2007 and 2016. Preoperative, intraoperative, and postoperative clinicopathological results were compared between early and non-early recurrence groups. Predictors of early recurrence were determined using statistical analyses.

RESULTS

Log-rank tests revealed a significant difference (P < .001) between recurrence within 3 to 6 months and 6 to 9 months. Early recurrence was subsequently defined as recurrence within 6 months. Patients were categorized into early recurrence (n = 104) and non-early recurrence groups (n = 389). The median overall survival of the early and non-early recurrence groups was 8.6 months and 42.6 months (P < .001), respectively. Preoperatively, high carbohydrate antigen 19-9 levels ≥120 U/mL, retroperitoneal invasion, and diabetes mellitus were identified as independent predictive risk factors for early recurrence according to multivariate analysis. Comparing survival rates among patients with 3, 2, 1, or none of these factors, the median overall survival was 17.6 (n = 90), 21.2 (n = 184), 47 (n = 141), and 61.5 (n = 73) months, respectively.

CONCLUSION

The optimal period that defines the early recurrence for resectable pancreatic ductal adenocarcinoma of the pancreatic head is 6 months. Tumor size ≥20 mm, preoperative carbohydrate antigen 19-9 levels ≥120 U/mL, retroperitoneal invasion of the tumor, and the presence of diabetes mellitus are independently associated with early recurrence.

Exploring the Role of Metabolites in Cancer and the Associated Nerve Crosstalk

Since Otto Warburg's first report on the increased uptake of glucose and lactate release by cancer cells, dysregulated metabolism has been acknowledged as a hallmark of cancer that promotes proliferation and metastasis. Over the last century, studies have shown that cancer metabolism is complex, and by-products of glucose and glutamine catabolism induce a cascade of both pro- and antitumorigenic processes. Some vitamins, which have traditionally been praised for preventing and inhibiting the proliferation of cancer cells, have also been proven to cause cancer progression in a dose-dependent manner. Importantly, recent findings have shown that the nervous system is a key player in tumor growth and metastasis via perineural invasion and tumor innervation. However, the link between cancer-nerve crosstalk and tumor metabolism remains unclear. Here, we discuss the roles of relatively underappreciated metabolites in cancer-nerve crosstalk, including lactate, vitamins, and amino acids, and propose the investigation of nutrients in cancer-nerve crosstalk based on their tumorigenicity and neuroregulatory capabilities. Continued research into the metabolic regulation of cancer-nerve crosstalk will provide a more comprehensive understanding of tumor mechanisms and may lead to the identification of potential targets for future cancer therapies.

CT Radiomic Features of Superior Mesenteric Artery Involvement in Pancreatic Ductal Adenocarcinoma: A Pilot Study

Background Current imaging methods for prediction of complete margin resection (R0) in patients with pancreatic ductal adenocarcinoma (PDAC) are not reliable. Purpose To investigate whether tumor-related and perivascular CT radiomic features improve preoperative assessment of arterial involvement in patients with surgically proven PDAC. Materials and Methods This retrospective study included consecutive patients with PDAC who underwent surgery after preoperative CT between 2012 and 2019. A three-dimensional segmentation of PDAC and perivascular tissue surrounding the superior mesenteric artery (SMA) was performed on preoperative CT images with radiomic features extracted to characterize morphology, intensity, texture, and task-based spatial information. The reference standard was the pathologic SMA margin status of the surgical sample: SMA involved (tumor cells ≤1 mm from margin) versus SMA not involved (tumor cells >1 mm from margin). The preoperative assessment of SMA involvement by a fellowship-trained radiologist in multidisciplinary consensus was the comparison. High reproducibility (intraclass correlation coefficient, 0.7) and the Kolmogorov-Smirnov test were used to select features included in the logistic regression model. Results A total of 194 patients (median age, 66 years; interquartile range, 60-71 years; age range, 36-85 years; 99 men) were evaluated. Aside from surgery, 148 patients underwent neoadjuvant therapy. A total of 141 patients' samples did not involve SMA, whereas 53 involved SMA. A total of 1695 CT radiomic features were extracted. The model with five features (maximum hugging angle, maximum diameter, logarithm robust mean absolute deviation, minimum distance, square gray level co-occurrence matrix correlation) showed a better performance compared with the radiologist assessment (model vs radiologist area under the curve, 0.71 [95% CI: 0.62, 0.79] vs 0.54 [95% CI: 0.50, 0.59]; P < .001). The model showed a sensitivity of 62% (33 of 53 patients) (95% CI: 51, 77) and a specificity of 77% (108 of 141 patients) (95% CI: 60, 84). Conclusion A model based on tumor-related and perivascular CT radiomic features improved the detection of superior mesenteric artery involvement in patients with pancreatic ductal adenocarcinoma. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Do and Kambadakone in this issue.

Can a simplified CT response criteria for vascular involvement in pancreatic adenocarcinoma after neoadjuvant therapy predict survival in patients who achieved subsequent R0 resection?

PURPOSE

To investigate if a simplified image based scoring system assessing treatment response after neoadjuvant therapy (NAT) can predict survival in patients with pancreatic ductal adenocarcinoma (PDAC) who achieved subsequent R0 resection.

METHODS

Retrospective analysis of 57 PDAC patients (male = 29, 51%) with mean age of 64 at diagnosis (range 42-79) who received NAT and R0 resection. Post-NAT overall, arterial and venous imaging response was characterized as improved, similar, or worse by 2 readers independently followed by consensus review. Kaplan-Meier Analysis was performed to compare overall survival (OS) with post-NAT overall imaging response. A Multivariable Cox proportional hazards analysis was performed to evaluate the association of the following variables with OS: overall, arterial and venous radiology response, clinical staging, postoperative CA19-9, and patient age.

RESULTS

At study conclusion, 30/57 patients were deceased (53%), 26/57 (46%) alive, and 1 patient unknown. Post-NAT, 39/57 (68.4%) had overall improved disease and 18/57 (31.6%) had similar disease. The median OS was 55.7 months (95% CI 33.4-not reached, NR) for those with improved disease vs. 53.9 months (95% CI 14.3-NR) with similar disease (p = 0.859) after NAT. Among all clinical parameters, only post-operative CA 19-9 level was associated with OS (p = 0.002) and PFS (p = 0.005), respectively.

CONCLUSION

Pancreatic cancer patients who underwent R0 resection showed no difference in survival when comparing those with similar vs improved disease on post-NAT imaging.

Predictors of conversion surgery in patients with pancreatic cancer who underwent neoadjuvant or palliative FOLFIRINOX treatment using baseline and follow-up CT

PURPOSE

We aimed to evaluate the predictive factors of conversion surgery in pancreatic adenocarcinoma (PAC) after neoadjuvant or palliative FOLFIRINOX using baseline and follow-up CT.

METHODS

We retrospectively included 189 patients who had undergone more than 4 cycles of FOLFIRINOX. We reviewed baseline CT (B-CT), 1st follow-up CT (1st-CT), and the preoperative or last follow-up CT (L-CT) and determined tumor size changes according to the Response Evaluation Criteria in Solid Tumors (RECIST 1.1). Extra-pancreatic perineural invasion (EPNI) and resectability using NCCN 2019 guideline were evaluated. Subgroup analysis by baseline resectability was performed.

RESULTS

B-CT included resectable (n = 25, 23.2%), borderline (n = 55, 29.1%), locally advanced (n = 44, 23.3%), and metastatic (n = 65, 34.4%) PAC. Seventy-four patients had undergone surgery (39.2%) with an 83.8% (62/74) R0 resection. For operability, resectable status at L-CT (hazard ratio (HR) 65.5; 95% confidence interval (CI) 5.0-865; P = 0.002), RECIST (partial response) at 1st-CT (HR 3.6; 95% CI 1.1-11.7; P = 0.032), and baseline borderline resectability (HR 8.6; 95% CI 1.6-46.4; P = 0.013) were important predictors. Based on a size reduction cut-off of 22.2%, the area under the receiver operating characteristic (ROC) curve (Az) was 0.761 (sensitivity = 70.3%, specificity = 74.8%). In subgroup analysis, RECIST (partial response) at 1st-CT was a significant predictor of locally advanced PAC (HR 32; 95% CI 4.5-227, P 0.001), and the optimal cut-off was 22.2% (Az = 0.914; sensitivity = 100%, specificity = 75%). Baseline tumor size ([Formula: see text] 4 cm) (HR 5.6, 95% CI 1.3-24.3, P = 0.022) and unresectable status at 1st-CT (HR 4.8, 95% CI 1.1-20.6, P = 0.035) were significantly associated with margin-positive resection.

CONCLUSION

Both baseline and follow-up CT findings are useful to predict conversion surgery for PAC after FOLFIRINOX.

Prediction of prognosis and resectability using MR imaging, clinical, and histopathological findings in patients with perihilar cholangiocarcinoma

PURPOSE

To predict poor overall survival (OS) and risk of residual tumor after surgery using MR imaging, clinical, and histopathological findings in perihilar cholangiocarcinoma.

METHODS

196 patients with perihilar cholangiocarcinoma who underwent preoperative MRI and curative-intent surgery were retrospectively included. MRI findings were assessed by two radiologists. Clinical characteristics and histopathological results such as serum carcinoembryonic antigen (CEA), carbohydrate antigen 19-9 (CA 19-9), T and N stage, and resection status, were also investigated. Cox regression analysis and the Kaplan-Meier method were used to identify prognostic factors for OS. We further analyzed the correlation between MRI features and residual tumors using logistic regression analysis.

RESULTS

The median OS was 25.0 ± 26.6 months. T stage (hazard ratio [HR] 6.26, p = 0.014), N stage (HR 1.86, p = 0.002), CA-19-9 >37 U/mL (HR 2.06, p < 0.001), enlarged LN on MRI (HR 1.69, p = 0.006), and residual tumor (HR 1.52, p = 0.034) were important predictors of poor survival. The 5-year OS of the complete resection group (n = 107) was significantly better than that of the residual tumor group (n = 89) (35.5% vs. 18.8%, p = 0.002). Additionally, peritumoral fat stranding (odds ratio[OR] 2.09, p = 0.027), Bismuth type III/IV (OR 1.95, p = 0.022), and common bile duct (CBD) involvement (OR 2.3, p = 0.008) on MRI were important predictors of residual tumors in univariate analyses. However, absence of peritumoral fat stranding was a significant independent predictor for complete resection (OR 1.99, p = 0.048) and showed the highest sensitivity, at 79.8%.

CONCLUSION

MR imaging, clinical and histopathological results are useful for predicting poor survival after surgery for perihilar cholangiocarcinoma. Furthermore, MRI findings, including peritumoral fat stranding, CBD involvement, and Bismuth type, are important for the prediction of residual tumors.

Real world outcomes of neoadjuvant chemotherapy and radiotherapy for borderline resectable pancreatic cancer: a multicentre observational study

BACKGROUND

Neoadjuvant therapy may increase the likelihood of complete (R0) resection for borderline resectable pancreatic cancer. The optimal approach is unknown and differs amongst treatment centres.

METHODS

We identified patients with biopsy-proven borderline resectable pancreatic adenocarcinoma who commenced neoadjuvant therapy between January 2012 and June 2019 at three centres in Sydney, Australia. Patterns of care and outcomes of varying approaches were examined.

RESULTS

Forty-eight patients were identified. Median age was 66 years (range: 41-84). Staging included endoscopic ultrasound in 98%, PET-CT scan in 77%, laparoscopy in 46%. Neoadjuvant regimens used were a combination of chemotherapy and chemo-radiation (58%), chemotherapy alone (13%) and chemoradiation alone (29%). Radiologic complete or partial response occurred in 33% and progression in 25%. Complete macroscopic surgical resection was achieved in 50%, and R0 resection in 38%. At median follow-up of 15 months, the 1-year and 2-year overall survival was 75% and 63% respectively, and the 1-year and 2-year progression-free survival was 50% and 29% respectively. Significant predictors of macroscopic resectability were radiologic response (p = 0.005) but not addition of radiotherapy to chemotherapy (OR 0.87, p = 0.81). Predictors of overall survival included baseline Ca19.9 level (p = 0.04) and a trend to the use of systemic chemotherapy (HR 0.51, p = 0.07), but not use of radiotherapy (HR 0.70, p = 0.47).

CONCLUSION

There is high variability in staging and neoadjuvant approaches for borderline resectable pancreas cancer. Despite aggressive neoadjuvant therapies, R0 resection and prolonged survival are uncommon. The incremental benefit of neoadjuvant radiotherapy after neoadjuvant chemotherapy was not demonstrated in this observational study.

CT-diagnosed extra-pancreatic extension of pancreatic ductal adenocarcinoma is a more reliable prognostic factor for survival than pathology-diagnosed extension

OBJECTIVES

To determine the correlation between CT-diagnosed extra-pancreatic extension of pancreatic ductal adenocarcinoma (PDAC), pathology-diagnosed extra-pancreatic extension, and survival in patients with PDAC.

METHODS

This retrospective study included 87 patients with resected PDAC. Two radiologists evaluated negative ((i) tumours surrounded by the pancreatic parenchyma and (ii) tumours contacting the pancreatic surface) or positive ((iii) tumours with peri-pancreatic strand appearances and/or with expansive growth) CT-diagnosed extra-pancreatic extension. Clinical, pathological, and CT imaging characteristics predicting disease-free survival (DFS) and overall survival (OS) were assessed using Cox proportional-hazards models. Diagnostic accuracy for pathology-diagnosed extra-pancreatic extension was also assessed.

RESULTS

CT-diagnosed extra-pancreatic extension (42/87 tumours, 48.3%; κ = 0.82) had a higher hazard ratio (HR) for the DFS (HR, 5.30; p < 0.01) and OS (HR, 5.31; p < 0.01) rates than pathology-diagnosed extension in univariable analyses. It was also an independent prognostic factor for the DFS (HR, 4.22; p < 0.01) and OS (HR, 4.38; p < 0.01) rates in multivariable analyses. Of 45 tumours without CT-diagnosed extra-pancreatic extension, pathology-diagnosed extra-pancreatic extension was observed in 2/8 (25.0%) and 32/37 (86.5%) tumours with CT categories (i) and (ii), respectively. However, the differences in the survival rates between patients with CT categories (i) and (ii) were insignificant, although those in the latter category had significantly better survival rates than those with CT-diagnosed extra-pancreatic extension (category (iii)).

CONCLUSIONS

CT-diagnosed extra-pancreatic extension was a better prognostic factor than pathology-diagnosed extension and considered an independent factor for the postoperative DFS and OS rates with reasonable frequency and high reproducibility, despite the low diagnostic accuracy for predicting pathology-diagnosed extra-pancreatic extension.

KEY POINTS

• A CT-diagnosed extra-pancreatic extension had a higher hazard ratio for both disease-free survival and overall survival compared to pathology-diagnosed extension in univariable survival analyses. • A CT-diagnosed extra-pancreatic extension was a significant independent predictor of both disease-free survival and overall survival, as observed in multivariable survival analyses. • Patients with tumours contacting with the pancreatic surface on CT images (CT category (ii)) showed similar survival rates to those whose tumours were surrounded by the pancreatic parenchyma (CT category (i)), although many tumours with CT category (ii) extended pathologically beyond the pancreas.

Assessment of Malignancy Potential in Intraductal Papillary Mucinous Neoplasms of the Pancreas on MDCT

RATIONALE AND OBJECTIVE

To assess the malignancy potential of intraduct papillary mucinous neoplasms (IPMNs) on multidetector-row computerized tomography according to the 2012 International Consensus Guidelines (ICG).

MATERIALS AND METHODS

This study retrospectively collected IPMNs confirmed by surgery from 2016 to 2019. The imaging findings of IPMNs were analyzed. IPMNs were classified as malignancy in the presence of high-grade dysplasia or invasive carcinoma and began in the presence of low- and intermediate-grade dysplasia.

RESULTS

A total of 207 patients (mean age: 63.7 ± 7.9 years) were included, and the prevalence of malignancy was 28.0% (58 of 207). According to the 2012 ICG, the imaging findings of IPMNs were divided into worrisome features (WFs) and high-risk stigmata (HRS). The malignancy of IPMN with only one WF was relatively low (1.4%, 3 of 207). In multivariate regression analyses, the independent factors of IPMNs were enhanced mural nodule ≥5 mm (odds ratio [OR] = 19.5, 95% confidence interval [CI] 6.8-55.4), abrupt change in the main pancreatic duct caliber with distal pancreatic atrophy (OR = 4.6, 95%CI 1.67-12.71), and thickened enhanced cyst walls (OR = 2.9, 95%CI 1.1-8.2). When the presence of more than two WFs or HRS (score ≥ 3) was regarded as indicating the malignancy potential of IPMNs on multidetector-row computerized tomography, the sensitivity, specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) were 89.7%, 75.8%, 79.7%, 59.1%, and 95.0%, respectively.

CONCLUSION

According to the ICG in 2012, patients with IPMNs with only one WF have a low risk for malignancy, and the presence of at least two WFs or any HRS (score ≥3) suggests malignant IPMNs.

Preoperative CT predictors of survival in patients with pancreatic ductal adenocarcinoma undergoing curative intent surgery

PURPOSE

To evaluate the associations between computed tomography (CT) imaging features extracted from the structured American Pancreatic Association (APA)/Society of Abdominal Radiology (SAR) template and overall survival in patients with resected pancreatic ductal adenocarcinoma (PDAC).

METHODS

This retrospective analysis included consecutive patients with PDAC who consented to genomic tumor testing and underwent preoperative imaging and curative intent surgical resection from December 2006 to July 2017. Two radiologists assessed preoperative CT imaging using the APA/SAR PDAC-reporting template. Univariable associations between overall survival and imaging variables were evaluated using Cox proportional hazards regression.

RESULTS

The study included 168 patients (66 years ± 11; 91 women). 126/168 patients (75%) received upfront surgical resection whereas 42/168 (25%) received neoadjuvant therapy prior to surgical resection. In the entire cohort, features associated with decreased overall survival were tumor arterial contact of any kind (hazard ratio (HR) 1.89, 95% CI 1.13-3.14, p = 0.020), tumor contact with the common hepatic artery (HR 2.33, 95% CI 1.35-4.04, p = 0.009), and portal vein deformity (HR 3.22, 95% CI 1.63-6.37, p = 0.003). In the upfront surgical group, larger tumor size was associated with decreased overall survival (HR 2.30, 95% CI 1.19-4.42, p = 0.013). In the neoadjuvant therapy group, the presence of venous collaterals was the only feature associated with decreased overall survival (HR 2.28, 95% CI 1.04-4.99, p = 0.042).

CONCLUSION

The application of the APA/SAR pancreatic adenocarcinoma reporting template may identify predictors of survival that can aid in preoperative stratification of patients.

Preoperative assessment of the resectability of pancreatic ductal adenocarcinoma on CT according to the NCCN Guidelines focusing on SMA/SMV branch invasion

OBJECTIVES

For patients with pancreatic adenocarcinoma (PAC), adequate determination of disease extent is critical for optimal management. We aimed to evaluate diagnostic accuracy of CT in determining the resectability of PAC based on 2020 NCCN Guidelines.

METHODS

We retrospectively enrolled 368 consecutive patients who underwent upfront surgery for PAC and preoperative pancreas protocol CT from January 2012 to December 2017. The resectability of PAC was assessed based on 2020 NCCN Guidelines and compared to 2017 NCCN Guidelines using chi-square tests. Overall survival (OS) was estimated using the Kaplan-Meier method and compared using log-rank test. R0 resection-associated factors were identified using logistic regression analysis.

RESULTS

R0 rates were 80.8% (189/234), 67% (71/106), and 10.7% (3/28) for resectable, borderline resectable, and unresectable PAC according to 2020 NCCN Guidelines, respectively (p < 0.001). The estimated 3-year OS was 28.9% for borderline resectable PAC, which was significantly lower than for resectable PAC (43.6%) (p = 0.004) but significantly higher than for unresectable PAC (0.0%) (p < 0.001). R0 rate was significantly lower in patients with unresectable PAC according to 2020 NCCN Guidelines (10.7%, 3/28) than in those with unresectable PAC according to the previous version (31.7%, 20/63) (p = 0.038). In resectable PAC, tumor size ≥ 3 cm (p = 0.03) and abutment to portal vein (PV) (p = 0.04) were independently associated with margin-positive resection.

CONCLUSIONS

The current NCCN Guidelines are useful for stratifying patients according to prognosis and perform better in R0 prediction in unresectable PAC than the previous version. Larger tumor size and abutment to PV were associated with margin-positive resection in patients with resectable PAC.

KEY POINTS

• The updated 2020 NCCN Guidelines were useful for stratifying patients according to prognosis. • The updated 2020 NCCN Guidelines performed better in the prediction of margin-positive resection in unresectable cases than the previous version. • Tumor size ≥ 3 cm and abutment to the portal vein were associated with margin-positive resection in patients with resectable pancreatic adenocarcinoma.

Preoperative CT-based detection of extrapancreatic perineural invasion in pancreatic cancer

Accuracy for computed tomography (CT) diagnosis of extrapancreatic perineural invasion (EPNI) in pancreatic ductal adenocarcinoma (PDAC), which is a significant cause of recurrence, has not been established. The aim of the study was to evaluate the diagnostic accuracy of CT in detecting EPNI preoperatively in resectable PDAC of the pancreatic head. Retrospective study design was approved by institutional review board. Preoperative CT-series of 46 patients with resectable PDAC were evaluated by two independent observers. Plexus Pancreaticus Capitalis-II (PPC-II) was assessed as this area is more susceptible for EPNI. All patients underwent surgery with dedicated histopathology, which served as the reference standard. Histologically EPNI was confirmed in 63.1%. Sensitivity of MDCT was 93.1% (95% confidence interval (CI) 77.23% to 99.15%), specificity 64.7% (95% CI 38.33% to 85.79%) with area under the curve (AUC) 0.789 for the first observer. Positive predictive value (PPV) was 81.82% (95% CI 70.12% to 89.62%), negative predictive value (NPV-84.62% (95% CI 57.98% to 95.64%) with diagnostic accuracy of 82.61% (95% CI 68.58% to 92.18%). Interobserver agreement showed k-value of 0.893 ([Formula: see text]), which represents very good agreement between observers. Median actual survival in patients without EPNI was 30 months (95% CI 18.284-41.716), in patients with EPNI-13 months (95% CI 12.115-13.885). CT provides sufficient diagnostic information to detect PPC-II invasion in patients with resectable PDAC of the pancreatic head. Preoperative detection of EPNI might be an additional argument to perform neoadjuvant chemotherapy in patients with resectable PDAC. It should be included in preoperative evaluation form of CT-findings.

CT-Radiomic Approach to Predict G1/2 Nonfunctional Pancreatic Neuroendocrine Tumor

RATIONALE AND OBJECTIVES

Tumor grading of nonfunctional pancreatic neuroendocrine tumors (NF-pNETs) determines the choice of clinical treatment and management. The pathological grade of pancreatic neuroendocrine tumors is usually assessed on postoperative specimens. The goal of our study is to establish a tumor grade (G) prediction model for preoperative G1/2 NF-pNETs using radiomics for multislice spiral CT image analysis.

MATERIALS AND METHODS

This retrospective study included a primary cohort of 59 patients and an independent validation cohort of 40 consecutive patients; their multislice spiral CT images were collected from October 2012 to October 2016 and October 2016 to June 2018, respectively. All 99 patients were diagnosed with clinicopathologically confirmed NF-pNETs. Most significant radiomic features were selected using the minimum redundancy and maximum relevance algorithm. Support vector machine classifier with a radial basis function-based predictive model was subsequently developed for clinical use.

RESULTS

A total of 585 radiomics features were extracted from every phase for each patient. Six of these radiomics features were identified as most discriminant features for G1 and G2 tumors and used to construct the tumor grade prediction model. The prediction model resulted in the area under the curve values of 0.968 (95% CI: 0.900-0.991) and 0.876 (95% CI: 0.700-0.963) for the training cohort and validation cohort, respectively. Sensitivity and specificity were 96.4% and 83.9%, and 90.9% and 88.9% for the training and validation cohorts, respectively. The decision curves indicated that if the threshold probability is above 0.1, using the rad-score in the current study on G1/2 NF-pNETs is more beneficial than the treat-all-patients scheme or the treat-none scheme.

CONCLUSION

Radiomics developed with a combination of nonenhanced and portal venous phases can achieve favorable predictive accuracy for histological grade for G1/G2 NF-pNETs.

Important CT and histopathological findings for recurrence and overall survival in patients with pancreatic ductal adenocarcinoma who underwent surgery after neoadjuvant FOLFIRINOX

OBJECTIVES

To investigate important factors for recurrence-free survival (RFS) and overall survival (OS) in patients with pancreatic ductal adenocarcinoma (PDA) who underwent surgery after neoadjuvant FOLFIRINOX using CT and histopathological findings.

MATERIALS AND METHODS

Sixty-nine patients with PDA who underwent surgery after neoadjuvant FOLFIRINOX were retrospectively included. All patients underwent baseline and first follow-up CT. Two reviewers assessed the CT findings and resectability based on the NCCN guideline. They graded extrapancreatic perineural invasion (EPNI) using a 3-point scale focused on 5 routes. Clinical and histopathological results, such as T- and N-stage, tumor regression grade (TRG) using the College of American Pathology (CAP) grading system, and resection status, were also investigated. Kaplan-Meier methods were used for RFS and OS. The Cox proportional hazard model and logistic regression model were used to identify significant predictive factors.

RESULTS

There were 57 patients (82.6%) without residual tumors (R0) and 12 patients (17.4%) with residual tumors (R1 or R2). The median RFS was 13 months (range 0~22 months). For RFS, EPNI on baseline CT (hazard ratio (HR) 2.53, 95% confidence interval (CI) 1.116-5.733, p = 0.026) and TRG (HR 1.76, 95% CI 1.000-3.076, p = 0.046) were important predictors of early recurrence. The mean OS was 48 months (range 11~35 months). For OS, TRG (HR 1.05, 95% CI 1.251-6.559, p = 0.013) was a significant factor. However, there were no independent predictors for residual tumors according to the CT findings.

CONCLUSION

EPNI on baseline CT and TRG were important prognostic factors for tumor recurrence. In addition, TRG was also an important prognostic factor for OS.

KEY POINTS

• CT and histopathological findings are helpful for predicting early recurrence and poor survival. • EPNI on baseline CT (HR 2.53, p = 0.026) is an important predictor of early recurrence. • The TRG is an important prognostic factor for early recurrence (HR 1.76, p = 0.046) and poor survival (HR 1.05, p = 0.013).

New method for the assessment of perineural invasion from perihilar cholangiocarcinoma

PURPOSE

Perineural invasion (PN) is often found in perihilar cholangiocarcinoma. New procedure was developed to assess PN around the right hepatic artery (RHA) using dual-energy computed tomography (DECT).

METHODS

Thirty patients with perihilar cholangiocarcinoma who underwent DECT before biliary drainage were retrospectively reviewed. Mask images, i.e., the periarterial layer (PAL) around the RHA and superior mesenteric artery (SMA), were made from late arterial phase DECT. The mean CT number of the PAL was measured.

RESULTS

Twenty patients with PN around the RHA were classified into the PN (+) group. The remaining 10 patients without PN and other 26 patients with other diseases that are never accompanied with PN were classified into the PN (-) group. The PAL ratio (the CT number of the PAL around the RHA relative to that around the SMA) was calculated. Both the mean CT number of the PAL around the RHA and the PAL ratio were significantly higher in the PN (+) group than in the PN (-) group. According to an ROC analysis, the predictive ability of the PAL ratio was superior. Using the cutoff value of the PAL ratio 1.009, a diagnosis of PN around the RHA was made with approximately 75% accuracy.

CONCLUSIONS

Assessment with CT number of the PAL reconstructed from DECT images is an easy and objective method to diagnose PN.

Imaging and Management of Pancreatic Cancer

Pancreatic cancer is an aggressive disease with rising incidence and high mortality despite advances in imaging and therapeutic options. Surgical resection is currently the only curative treatment, with expanding roles for adjuvant and neoadjuvant chemoradiation. Accurate detection, staging, and post-treatment monitoring of pancreatic cancer are critical to improving survival and imaging plays a central role in the multidisciplinary approach to this disease. This article will provide a broad overview of the imaging and management of pancreatic cancer with a focus on diagnosis and staging, operative and nonoperative treatments, and post-therapeutic appearances after surgery and chemoradiation therapy.

Extrapancreatic Nerve Plexus Invasion on Imaging Predicts Poor Survival After Upfront Surgery for Anatomically Resectable Pancreatic Cancer

OBJECTIVES

This study aimed to analyze the risk factors for poor survival of the patients with anatomically resectable pancreatic ductal adenocarcinoma (PDAC), focusing on detailed computed tomography (CT) findings of tumor extent to the peripancreatic tissue.

METHODS

The study included 192 patients who underwent upfront pancreaticoduodenectomy for anatomically resectable PDAC. Preoperative CT images were rereviewed by an experienced radiologist for the pattern of tumor extension to the surrounding tissue: biliary, duodenal, serosal, retroperitoneal, portal venous, arterial, extrapancreatic nerve plexus, and other-organ invasion. Imaging findings and other clinical data that could be obtained before surgery were evaluated for their association with a shorter disease-specific survival (DSS) and recurrence-free survival (RFS).

RESULTS

Of the 192 anatomically resectable PDAC patients, extrapancreatic nerve plexus invasion was observed on CT in 38 patients (20%), and this finding was independently associated with a shorter DSS (hazard ratio, 2.258; P < 0.001) and RFS (hazard ratio, 2.665; P < 0.001). The median survival of patients with and without extrapancreatic nerve plexus invasion on CT was 19.7 versus 38.5 months (P < 0.001).

CONCLUSIONS

Extrapancreatic nerve plexus invasion was shown as an only CT finding associated with a shorter DSS and RFS after upfront surgery for the patients with anatomically resectable PDAC.

Imaging diagnosis and staging of pancreatic ductal adenocarcinoma: a comprehensive review

Pancreatic ductal adenocarcinoma (PDAC) has continued to have a poor prognosis for the last few decades in spite of recent advances in different imaging modalities mainly due to difficulty in early diagnosis and aggressive biological behavior. Early PDAC can be missed on CT due to similar attenuation relative to the normal pancreas, small size, or hidden location in the uncinate process. Tumor resectability and its contingency on the vascular invasion most commonly assessed with multi-phasic thin-slice CT is a continuously changing concept, particularly in the era of frequent neoadjuvant therapy. Coexistent celiac artery stenosis may affect the surgical plan in patients undergoing pancreaticoduodenectomy. In this review, we discuss the challenges related to the imaging of PDAC. These include radiological and clinical subtleties of the tumor, evolving imaging criteria for tumor resectability, preoperative diagnosis of accompanying celiac artery stenosis, and post-neoadjuvant therapy imaging. For each category, the key imaging features and potential pitfalls on cross-sectional imaging will be discussed. Also, we will describe the imaging discriminators of potential mimickers of PDAC.

Preoperative prediction of futile surgery in patients with radiologically resectable or borderline resectable pancreatic adenocarcinoma

BACKGROUND AND AIM

The aim of this study is to identify the predictive factors for futile surgery in patients with radiologically resectable or borderline resectable pancreatic cancer and to develop a prediction model.

METHODS

This retrospective study included patients who underwent pancreatic surgery for pancreatic cancer between 2006 and 2017. To identify independent risk factors for futile surgery, logistic regression and random forest analyses were performed in the training cohort, based on which a nomogram was established. The predictive accuracy and discriminative ability of the nomogram were validated in the validation cohort.

RESULTS

Of 389 patients who underwent pancreatic surgery, the laparotomy was futile in 40 patients (10.3%). In the training cohort, the univariate and multivariate logistic regression analyses revealed that serum carbohydrate antigen 19-9 level of ≥ 150 U/mL (P = 0.003), the presence of suspicious lymph node (P = 0.013), and more extensive peripancreatic tumor infiltration (P < 0.001) were independent predictive factors for futile surgery. The bootstrap-corrected concordance index of the nomogram was high in the training cohort, 0.826 with a 95% confidence interval of 0.745-0.907. This model also showed a good discriminative performance in the validation cohort, with a concordance index of 0.831.

CONCLUSIONS

We established and validated a novel nomogram that predicts the risk of futile surgery due to occult distant metastasis in patients with radiologically resectable or borderline resectable pancreatic cancer.

Demystifying the mesenteric root lesions

OBJECTIVE

The aim of this article is to describe the normal anatomy of the root of the small bowel mesentery (RSBM) as well as the multidetector computed tomography (MDCT) features of the various primary and secondary lesions that affect the RSBM.

RESULTS

The small bowel mesentery attaches the jejunum and ileum to the posterior abdominal wall, the line of attachment forming the RSBM. Several primary as well as secondary lesions involve the RSBM. The RSBM has anatomical contiguity with the mesocolon and other peritoneal ligaments, which forms a route for the spread of infection, neoplasms as well as several other abdominal pathologies. MDCT plays an important role in the evaluation of mesenteric root lesions.

CONCLUSION

Familiarity with the lesions involving the RSBM and their characteristic appearances on MDCT is important in giving thoughtful differential diagnosis and guiding the treating physician in further management.

Dual-Energy CT of the Pancreas

This article explores the technical background of dual-energy CT (DECT) imaging along with its basic principles, before turning to a review of the various DECT applications specific to pancreatic imaging. In light of the most recent literature, we will review the constellation of DECT applications available for pancreatic imaging in both oncologic and non-oncologic applications. We emphasize the increased lesion conspicuity and the improved tissue characterization available with DECT post-processing tools. Finally, future clinical applications and opportunities for research will be overviewed.

Staging of pancreatic cancer: resectable, borderline resectable, and unresectable disease

Pancreatic ductal adenocarcinoma (PDAC) is a relatively common malignancy that carries an overall poor prognosis, with five-year survival below 10%. Despite ongoing research, surgical resection remains the only potentially curative treatment. Therefore, accurate identification of those patients who would benefit from surgical resection is of paramount importance. High-quality imaging and image interpretation is central to this process. Radiology helps in the determination of whether patients are resectable, borderline resectable, or unresectable and guides treatment planning.

MDCT findings predicting post-operative residual tumor and survival in patients with pancreatic cancer

OBJECTIVES

To predict residual tumor (R) classification and overall survival (OS) on preoperative MDCT in patients who underwent first-line surgery for pancreatic ductal adenocarcinoma (PDA).

METHODS

Three hundred sixteen patients with PDA who underwent MDCT and first-line surgery were included. Patients were divided into a test (n = 216) and a validation group (n = 100). The R classification was categorized into R0 (no residual tumor) and R1/R2 (microscopic/macroscopic residual tumor). We assessed the correlation between the MDCT findings and the R classification. For survival analysis, we used the Kaplan-Meier estimation and Cox proportional hazard model to determine the prognostic factors for OS. Validation of the prediction models for the R classification and OS was performed using C statistics and calibration plot.

RESULTS

Peritumoral fat stranding (odds ratio (OR) 3.826), suspicious distant metastasis (OR 2.916), portal vein involvement (OR 2.795), and tumor size (OR 1.045) were independent predictors for residual tumor (p < .05). On survival analysis, common hepatic artery involvement (hazard ratio (HR) 5.656), R1/R2 stage (HR 2.476), and N1 stage (HR 1.745) were predictors of poor OS (p < .05). C statistics for prediction models for R classification and OS were 0.816 and 0.662, respectively. Calibration plots showed good predictive performance in a high probability of the R1/R2 stage or poor OS.

CONCLUSION

Preoperative MDCT is useful for predicting the R classification using the tumor size, peritumoral fat stranding, portal vein involvement, and suspicious distant metastasis, as well as for anticipating poor OS using the N1 stage, common hepatic artery involvement, and R1/R2 stage in patients with PDA.

KEY POINTS

• Thorough assessment of the involvement of common hepatic artery or portal vein and peritumoral fat stranding is warranted for predicting prognosis in patients with pancreatic ductal adenocarcinoma. • Not only encasement but also abutment of common hepatic artery or portal vein by tumor predicts poor prognosis after upfront surgery. • If residual tumor or poor overall survival is anticipated on preoperative MDCT, neoadjuvant treatment can be performed.

Visualization of the fat planes between the pancreas and the adjacent organs and blood vessels using multi-detector computed tomography

PURPOSE

To explore individual variations in visibility of the fat planes between the pancreatic parenchyma and adjacent organs and blood vessels using the multi-detector-computed tomography (MDCT).

METHODS

Abdominal contrast-enhanced MDCT examinations of 520 consecutive adult individuals were retrospectively analysed by exploring the presence of visible fat planes between the healthy pancreas and the following surrounding structures: stomach, descending duodenum (D2), splenic, portal, superior mesenteric vein (SV, PV, SMV), inferior vena cava (IVC), and coeliac trunk, common hepatic and superior mesenteric artery (CT, HA and SMA). Spearman's rank correlation coefficient (r_S) was used to assess the correlation of individual gender, age, body mass and BMI, and visible fat planes towards particular surrounding structures.

RESULTS

Fat planes between the pancreatic parenchyma and surrounding structures was visible as follows: stomach in 76%, D2 11.7%, SV 51.5%, PV 0%, SMV 28.8%, IVC 80.8%, CT 99.4%, HA 90.4% and SMA in 100% participants. The presence of visible fat planes significantly correlated (p < 0.001) with body mass for stomach (r_S = 0.367), D2 (r_S = 0.247), SV (r_S = 0.355), SMV (r_S = 0.384) and IVC (r_S = 0.259); BMI for stomach (r_S = 0.292), SV (r_S = 0.248), SMV (r_S = 0.290) and IVC (r_S = 0.216); age for D2 (r_S = 0.363), SV (r_S = 0.276) and SMV (r_S = 0.409); and male gender for stomach (r_S = 0.160) and SV (r_S = 0.198).

CONCLUSION

Fat planes around the pancreatic parenchyma in the MDCT scan was almost always visible towards the adjacent magistral visceral arteries and IVC, always invisible towards the PV, and variably visible towards the SV, SMV, stomach and duodenum depending on the individual body mass, BMI, age and gender.

MRI evaluation of pancreatic ductal adenocarcinoma: diagnosis, mimics, and staging

The radiologist's role in the evaluation of pancreatic ductal adenocarcinoma remains critical in the management of this deadly disease. Imaging plays a vital role in the diagnosis and staging of pancreatic cancer. Although CT is more commonly used for staging pancreatic cancer, MR is increasingly playing an important role in this regard. In our institution, all pancreatic malignancies undergo staging with MRI. In this pictoral essay, we illustrate the MR imaging features of pancreatic ductal adenocarcinoma and its mimics, and we also discuss pearls and pitfalls in MR staging of pancreatic carcinoma.

Ping-Pong-Tumor and Host in Pancreatic Cancer Progression

Metastasis is the main cause of high pancreatic cancer (PaCa) mortality and trials dampening PaCa mortality rates are not satisfying. Tumor progression is driven by the crosstalk between tumor cells, predominantly cancer-initiating cells (CIC), and surrounding cells and tissues as well as distant organs, where tumor-derived extracellular vesicles (TEX) are of major importance. A strong stroma reaction, recruitment of immunosuppressive leukocytes, perineural invasion, and early spread toward the peritoneal cavity, liver, and lung are shared with several epithelial cell-derived cancer, but are most prominent in PaCa. Here, we report on the state of knowledge on the PaCIC markers Tspan8, alpha6beta4, CD44v6, CXCR4, LRP5/6, LRG5, claudin7, EpCAM, and CD133, which all, but at different steps, are engaged in the metastatic cascade, frequently via PaCIC-TEX. This includes the contribution of PaCIC markers to TEX biogenesis, targeting, and uptake. We then discuss PaCa-selective features, where feedback loops between stromal elements and tumor cells, including distorted transcription, signal transduction, and metabolic shifts, establish vicious circles. For the latter particularly pancreatic stellate cells (PSC) are responsible, furnishing PaCa to cope with poor angiogenesis-promoted hypoxia by metabolic shifts and direct nutrient transfer via vesicles. Furthermore, nerves including Schwann cells deliver a large range of tumor cell attracting factors and Schwann cells additionally support PaCa cell survival by signaling receptor binding. PSC, tumor-associated macrophages, and components of the dysplastic stroma contribute to perineural invasion with signaling pathway activation including the cholinergic system. Last, PaCa aggressiveness is strongly assisted by the immune system. Although rich in immune cells, only immunosuppressive cells and factors are recovered in proximity to tumor cells and hamper effector immune cells entering the tumor stroma. Besides a paucity of immunostimulatory factors and receptors, immunosuppressive cytokines, myeloid-derived suppressor cells, regulatory T-cells, and M2 macrophages as well as PSC actively inhibit effector cell activation. This accounts for NK cells of the non-adaptive and cytotoxic T-cells of the adaptive immune system. We anticipate further deciphering the molecular background of these recently unraveled intermingled phenomena may turn most lethal PaCa into a curatively treatable disease.

Cinematic rendering of pancreatic neoplasms: preliminary observations and opportunities

Pancreatic cancer is the third most common cause of cancer death and CT is the most commonly used modality for the initial evaluation of suspected pancreatic cancer. Post-processing of CT data into 2D multiplanar and 3D reconstructions has been shown to improve tumor visualization and assessment of tumor resectability compared to axial slices, and is considered the standard of care. Cinematic rendering is a new 3D-rendering technique that produces photorealistic images, and it has the potential to more accurately depict anatomic detail compared to traditional 3D reconstruction techniques. The purpose of this article is to describe the potential application of CR to imaging of pancreatic neoplasms. CR has the potential to improve visualization of subtle pancreatic neoplasms, differentiation of solid and cystic pancreatic neoplasms, assessment of local tumor extension and vascular invasion, and visualization of metastatic disease.

Advances in Diagnostic and Intraoperative Molecular Imaging of Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) has a dismal prognosis. To improve outcomes, there is a critical need for improved tools for detection, accurate staging, and resectability assessment. This could improve patient stratification for the most optimal primary treatment modality. Molecular imaging, used in combination with tumor-specific imaging agents, can improve established imaging methods for PDAC. These novel, tumor-specific imaging agents developed to target specific biomarkers have the potential to specifically differentiate between malignant and benign diseases, such as pancreatitis. When these agents are coupled to various types of labels, this type of molecular imaging can provide integrated diagnostic, noninvasive imaging of PDAC as well as image-guided pancreatic surgery. This review provides a detailed overview of the current clinical imaging applications, upcoming molecular imaging strategies for PDAC, and potential targets for imaging, with an emphasis on intraoperative imaging applications.

Pancreatic Adenocarcinoma Staging in the Era of Preoperative Chemotherapy and Radiation Therapy

Pancreatic ductal adenocarcinoma (PDA) remains among the most challenging malignancies to treat. At diagnosis, the tumor often already extends beyond the confines of the pancreas, spreading to an extent such that primary surgery with curative intent is very rarely feasible. Considerable momentum is now being given to a treatment strategy involving neoadjuvant chemotherapy or chemotherapy and radiation therapy in patients with nonmetastatic PDA. The main advantage of this strategy is better selection of patients likely to benefit from curative-intent surgery through the achievement of negative resection margins. Patients with rapidly progressive disease are identified and are spared ineffective surgery with its attendant morbidity. Neoadjuvant therapy can downstage tumors classified as locally advanced at initial imaging studies to resectable tumors. However, the imaging study evaluation of the response to neoadjuvant therapy is extremely complex. Thus, the diagnostic performance of imaging studies is not sufficient to ensure the accurate selection of patients in whom negative-margin resection is likely to be achieved. More specifically, standard criteria for predicting vascular invasion, based on the amount of tumor-vessel contact, are not valid after neoadjuvant therapy. ^©RSNA, 2018.

Tumor heterogeneity of pancreas head cancer assessed by CT texture analysis: association with survival outcomes after curative resection

The value of image based texture features as a powerful method to predict prognosis and assist clinical management in cancer patients has been established recently. However, texture analysis using histograms and grey-level co-occurrence matrix in pancreas cancer patients has rarely been reported. We aimed to analyze the association of survival outcomes with texture features in pancreas head cancer patients. Eighty-eight pancreas head cancer patients who underwent preoperative CT images followed by curative resection were included. Texture features using different filter values were obtained. The texture features of average, contrast, correlation, and standard deviation with no filter, and fine to medium filter values as well as the presence of nodal metastasis were significantly different between the recurred (n = 70, 79.5%) and non-recurred group (n = 18, 20.5%). In the multivariate Cox regression analysis, lower standard deviation and contrast and higher correlation with lower average value representing homogenous texture were significantly associated with poorer DFS (disease free survival), along with the presence of lymph node metastasis. Texture parameters from routinely performed pre-operative CT images could be used as an independent imaging tool for predicting the prognosis in pancreas head cancer patients who underwent curative resection.

Management of Borderline Resectable Pancreatic Cancer

With the rapid development of imaging modalities and surgical techniques, the clinical entity representing tumors that are intermediate between resectable and unresectable pancreatic adenocarcinoma has been identified has been termed "borderline resectable" (BR). These tumors are generally amenable for resection but portend an increased risk for positive margins after surgery and commonly necessitate vascular resection and reconstruction. Although there is a lack of consensus regarding the appropriate definition of what constitutes a BR pancreatic tumor, it has been demonstrated that this intermediate category carries a particular prognosis that is in between resectable and unresectable disease. In order to downstage the tumor and increase the probability of clear surgical margins, neoadjuvant therapy is being increasingly utilized and studied. There is a lack of high-level evidence to establish the optimal treatment regimen for BR tumors. When resection with negative margins is achieved after neoadjuvant therapy, the prognosis for BR tumors approaches and even exceeds that for resectable disease. This review presents the current definitions, different treatment approaches, and the clinical outcomes of BR pancreatic cancer.

Duodenal invasion by pancreatic adenocarcinoma: MDCT diagnosis of an aggressive imaging phenotype and its clinical implications

Despite advances in oncologic and imaging technology, pancreatic ductal adenocarcinoma remains a highly deadly disease. The only curative option, pancreaticoduodenectomy or pancreatectomy, carries a significant morbidity. Current imaging plays a role in pre-operative staging to determine the probability of achieve disease-free margins. However, a small but not insignificant number of pancreatic cancers have a relatively higher aggressive biology, despite being resectable based on traditional criteria. Recently, imaging biomarkers that serve as a surrogate for tumors with such aggressive phenotype have been described. These include duodenal invasion and extrapancreatic perineural invasion. This review will focus on the former highlighting the summary of literature supporting duodenal invasion as a surrogate for aggressive disease as well as review its MDCT imaging features.

Extrapancreatic perineural invasion in pancreatic adenocarcinoma

Pancreatic ductal adenocarcinoma continues to be a highly lethal disease, despite advances in modern medicine. Curative surgical options continue to carry significant morbidity and offer little improvement in overall 5-year survival. Currently, imaging plays an essential role in the pre-operative evaluation of patients who are undergoing evaluation for resection. However, some pancreatic cancers have particularly aggressive biology, despite appearing resectable by conventional imaging criteria. Imaging biomarkers that serve as surrogates for tumors with such aggressive phenotype have been recently described, namely duodenal invasion and extrapancreatic perineural invasion. In this pictorial review, we will summarize key concepts of extrapancreatic perineural invasion, describe its association with a poor prognosis, and highlight the role of imaging in its detection.

'Trident sign' in pelvis: sinister sign with poor prognosis

The perineural spread of the cancer through the lumbosacral plexus gives an appearance of 'trident sign' on contrast-enhanced CT scan and MRI. It is associated with adverse survival rates and carries a poor prognostic value.

Novel Diagnostic and Predictive Biomarkers in Pancreatic Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal disease for a multitude of reasons including very late diagnosis. This in part is due to the lack of understanding of the biological behavior of PDAC and the ineffective screening for this disease. Significant efforts have been dedicated to finding the appropriate serum and imaging biomarkers to help early detection and predict response to treatment of PDAC. Carbohydrate antigen 19-9 (CA 19-9) has been the most validated serum marker and has the highest positive predictive value as a stand-alone marker. When combined with carcinoembryonic antigen (CEA) and carbohydrate antigen 125 (CA 125), CA 19-9 can help predict the outcome of patients to surgery and chemotherapy. A slew of novel serum markers including multimarker panels as well as genetic and epigenetic materials have potential for early detection of pancreatic cancer, although these remain to be validated in larger trials. Imaging studies may not correlate with elevated serum markers. Critical features for determining PDAC include the presence of a mass, dilated pancreatic duct, and a duct cut-off sign. Features that are indicative of early metastasis includes neurovascular bundle involvement, duodenal invasion, and greater post contrast enhancement. 18-F-fluorodeoxyglucose (18-FDG) radiotracer uptake and changes following treatment may predict patient overall survival following treatment. Similarly, pretreatment apparent diffusion coefficient (ADC) values may predict prognosis with lower ADC lesions having worse outcome. Although these markers have provided significant improvement in the care of pancreatic cancer patients, further advancements can be made with perhaps better combination of markers or discovery of unique marker(s) to pancreatic cancer.