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.

T2 gallbladder cancer shows substantial survival variation between continents and this is not due to histopathologic criteria or pathologic sampling differences.

Published data on survival of T2 gallbladder carcinoma (GBC) from different countries show a wide range of 5-year survival rates from 30-> 70%. Recently, studies have demonstrated substantial variation between countries in terms of their approach to sampling gallbladders, and furthermore, that pathologists from different continents apply highly variable criteria in determining stage of invasion in this organ. These findings raised the question of whether these variations in pathologic evaluation could account for the vastly different survival rates of T2 GBC reported in the literature. In this study, survival of 316 GBCs from three countries (Chile n = 137, South Korea n = 105, USA n = 74), all adequately sampled (with a minimum of five tumor sections examined) and histopathologically verified as pT2 (after consensus examination by expert pathologists from three continents), was analyzed. Chilean patients had a significantly worse prognosis based on 5-year all-cause mortality (HR: 1.89, 95% CI: 1.27-2.83, p = 0.002) and disease-specific mortality (HR: 2.41, 95% CI: 1.51-3.84, p < 0.001), compared to their South Korean counterparts, even when controlled for age and sex. Comparing the USA to South Korea, the survival differences in all-cause mortality (HR: 1.75, 95% CI: 1.12-2.75, p = 0.015) and disease-specific mortality (HR: 1.94, 95% CI: 1.14-3.31, p = 0.015) were also pronounced. The 3-year disease-specific survival rates in South Korea, the USA, and Chile were 75%, 65%, and 55%, respectively, the 5-year disease-specific survival rates were 60%, 50%, and 50%, respectively, and the overall 5-year survival rates were 55%, 45%, and 35%, respectively. In conclusion, the survival of true T2 GBC in properly classified cases is neither as good nor as bad as previously documented in the literature and shows notable geographic differences even in well-sampled cases with consensus histopathologic criteria. Future studies should focus on other potential reasons including biologic, etiopathogenetic, management-related, populational, or healthcare practice-related factors that may influence the survival differences of T2 GBC in different regions.

Natural history and optimal treatment strategy of intraductal papillary mucinous neoplasm of the pancreas: Analysis using a nomogram and Markov decision model.

BACKGROUND/PURPOSE: With the increase in detection of intraductal papillary mucinous neoplasms (IPMN), a tailored approach is needed. This study was aimed at exploring the natural history of IPMN and suggest optimal treatment based on malignancy risk using a nomogram and Markov decision model. METHODS: Patients with IPMN who underwent surveillance or surgery were included. Changes in worrisome features/high-risk stigmata and malignancy conversion rate were assessed. Life expectancy and quality-adjusted life year (QALY) were compared using a nomogram predicting malignancy. RESULTS: Overall, 2006 patients with histologically confirmed or radiologically typical IPMN were enrolled. Of these, 1773 (88.4%), 81 (4.0%), and 152 (7.6%), respectively, had branch duct (BD)-, main duct-, and mixed-type IPMN at initial diagnosis. The cumulative risk of developing worrisome feature or high-risk stigmata was 19.0% and 35.0% at 5- and 10-year follow-up, respectively. The progression of malignancy rate at 10-year follow-up was 79.9% for main and mixed IPMNs and 5.9% for BD-IPMN. Nomogram-based malignancy risk prediction is well correlated with natural history based on pathologic biopsy and shows good stratification of survival. The decision model recommends surgery to maximize survival and QALY especially in those with >35% malignancy risk. CONCLUSIONS: Compared with main duct- and mixed-type IPMN, which have a high risk of malignancy (79.9%), BD-IPMN is very indolent (5.9%). The nomogram-based decision model suggests surgery rather than surveillance for patients with a high malignancy risk. The optimal treatment strategy between surgery and surveillance should consider patients' health status, malignancy risk, and centers' experience.

Assessment of hepatic sinusoidal obstruction syndrome with intravoxel incoherent motion diffusion-weighted imaging: An experimental study in a rat model.

BACKGROUND: Intravoxel incoherent motion (IVIM) diffusion-weighted imaging (DWI) parameters may reflect perfusion and diffusion changes in hepatic sinusoidal obstruction syndrome (SOS). PURPOSE: To investigate the feasibility of IVIM-DWI in the noninvasive assessment of hepatic SOS in an experimental rat model. STUDY TYPE: Animal study. POPULATION/SUBJECTS: Forty-four rats were administered different doses (90 or 160 mg/kg) of monocrotaline by gavage either 48 or 72 hours before MRI to induce different degrees of hepatic SOS, and another 10 rats served as controls. FIELD STRENGTH/SEQUENCE: 3T scanner, IVIM-DWI using nine b values (0-800 sec/mm2 ). ASSESSMENT: Histologically, rats were classified as having none (n = 10), mild (n = 8), moderate (n = 19), or severe SOS (n = 17). The apparent diffusion coefficient (ADC) and IVIM-derived parameters (D: true diffusion coefficient, D*: pseudo-diffusion coefficient, and f: perfusion fraction) of the liver parenchyma were measured. STATISTICAL TESTS: IVIM-DWI parameters were compared according to histologic grades of SOS (none, mild, moderate, and severe), and receiver operating characteristic (ROC) curve analysis was performed to determine the diagnostic accuracy. RESULTS: ADC, D, and f of the liver parenchyma were significantly different according to SOS severity groups (Ps < 0.01) and significantly decreased as SOS severity increased (rho = -0.323, -0.313, and -0.700; P = 0.017, 0.021, and <0.001, respectively). Means of f in none, mild, moderate, and severe SOS were 17.2%, 13.3%, 12.3%, and 11.1%, respectively. Among ADC and IVIM-derived parameters, f provided the highest area under the ROC curves for detecting ≥mild, ≥moderate, and severe SOS (0.991, 0.890, and 0.803, respectively). DATA CONCLUSION: IVIM-DWI may be useful in the diagnosis and severity assessment of hepatic SOS. LEVEL OF EVIDENCE: 2 Technical Efficacy Stage: 2 J. Magn. Reson. Imaging 2020;51:81-89.

Preoperative MDCT Assessment of Resectability in Borderline Resectable Pancreatic Cancer: Effect of Neoadjuvant Chemoradiation Therapy.

OBJECTIVE: The purpose of this study is to evaluate the diagnostic performance of MDCT in assessing tumor resectability in patients with borderline resectable pancreatic cancers after receiving neoadjuvant chemoradiation therapy (CRT) in comparison with those undergoing upfront surgery. SUBJECTS AND METHODS: Thirty-seven patients with borderline resectable pancreatic cancers were randomly allocated to the neoadjuvant CRT group (arm 1; n = 18) or up-front surgery group (arm 2; n = 19). Three radiologists rated the likelihood of local resectability on a 5-point scale at preoperative MDCT in two separate sessions (session 1: post-CRT of arm 1, baseline of arm 2; session 2: using new imaging criteria reflecting the changes during CRT of arm 1). The AUC of each reviewer, as well as sensitivity, specificity, and accuracy based on consensus interpretation, were compared between arms and sessions. RESULTS: For local resectability (n = 30), AUC values at session 1 were 0.664, 0.669, and 0.588 for reviewers 1, 2, and 3, respectively, and were not significantly different between arms 1 (n = 15; 0.759, 0.713, and 0.593) and 2 (n = 15; 0.852, 0.685, and 0.722) (p > 0.05). In arm 1, MDCT sensitivity, specificity, accuracy were 22%, 100%, and 53%, respectively, at session 1 versus 78%, 67%, and 73%, respectively, at session 2 (p > 0.05). CONCLUSION: In patients with borderline resectable pancreatic cancers, neoadjuvant CRT did not significantly decrease the performance of MDCT for the prediction of local resectability. However, by considering post-CRT changes, such as nonprogression in tumor-vascular contact, MDCT may provide better sensitivity for locally resectable disease.

Preoperative Assessment of Pancreatic Cancer with FDG PET/MR Imaging versus FDG PET/CT Plus Contrast-enhanced Multidetector CT: A Prospective Preliminary Study.

Purpose To determine the diagnostic performance of fluorine 18 fluorodeoxyglucose (FDG) positron emission tomography (PET)/magnetic resonance (MR) imaging in the preoperative assessment of pancreatic cancer in comparison with that of FDG PET/computed tomography (CT) plus contrast material-enhanced multidetector CT. Materials and Methods This prospective study was approved by the institutional review board; written informed consent was obtained. Thirty-seven patients with 39 pancreatic tumors underwent preoperative FDG PET/MR imaging, PET/CT, and contrast-enhanced multidetector CT. The authors measured maximal and mean standardized uptake values (SUVmax and SUVmean, respectively) of pancreatic cancer at PET/MR imaging and PET/CT. Two radiologists independently reviewed the two imaging sets (set 1, PET/MR imaging; set 2, PET/CT plus multidetector CT) to determine tumor resectability according to a five-point scale, N stage (N0 or N positive), and M stage (M0 or M1). With use of clinical-surgical-pathologic findings as the standard of reference (n = 20), diagnostic performances of the two imaging sets were compared by using the McNemar test. Results Both SUVmax and SUVmean of pancreatic tumors showed strong correlations between PET/MR imaging and PET/CT (r = 0.897 and 0.890, respectively; P < .001). The diagnostic performance of PET/MR imaging was not significantly different from that of PET/CT plus multidetector CT in the assessment of tumor resectability (area under the receiver operating characteristic curve: 0.891 vs 0.776, respectively, for reviewer 1 [P = .109] and 0.859 vs 0.797 for reviewer 2 [P = .561]), N stage (accuracy: 54% [seven of 13 patients] vs 31% [four of 13 patients]; P = .250 for both reviewers), and M stage (accuracy: 94% [16 of 17 patients] vs 88% [15 of 17 patients] for reviewer 1 [P > .999] and 94% [16 of 17 patients] vs 82% [14 of 17 patients] for reviewer 2 [P = .500]). Conclusion FDG PET/MR imaging showed a diagnostic performance similar to that of PET/CT plus contrast-enhanced multidetector CT in the preoperative evaluation of the resectability and staging of pancreatic tumors. © RSNA, 2016 Online supplemental material is available for this article.

Assessment of Malignant Potential in Intraductal Papillary Mucinous Neoplasms of the Pancreas: Comparison between Multidetector CT and MR Imaging with MR Cholangiopancreatography.

PURPOSE: To compare the diagnostic performance of multidetector computed tomography (CT) and magnetic resonance (MR) imaging with MR cholangiopancreatography (MRCP) in identifying the malignant potential of pancreatic intraductal papillary neoplasms (IPMNs) and evaluate their intermodality agreement. MATERIALS AND METHODS: Institutional review board approval was obtained, and the requirement for informed consent was waived for this retrospective study. In 129 patients with pathologically proved pancreatic IPMNs, three reviewers independently evaluated their preoperative CT and MR imaging with MRCP findings. Intermodality agreement between multidetector CT and MR imaging with MRCP, as well as interobserver agreement of each imaging modality, for depicting high-risk stigmata and worrisome features were assessed. Diagnostic values of other signs of overt malignancy, including the presence of a parenchymal mass and local-regional extension, were analyzed. Diagnostic performance and intermodality agreement were assessed by using receiver operating characteristics (ROC) curve analysis and weighted κ statistics. RESULTS: Overall, multidetector CT and MR imaging with MRCP were similar in their ability to depict signs suspicious or indicative of malignancy in patients with IPMN (area under the ROC curve [AUC] = 0.82 for both), with good intermodality agreement (κ = 0.75) and moderate interobserver agreement (κ = 0.47-0.59) when high-grade dysplasia was used as the cutoff for malignancy. When parenchymal masses and local-regional extensions were also considered as overt signs of malignancy, the ability to identify invasive IPMNs significantly increased (AUC = 0.87 for CT and AUC = 0.88 for MR imaging), with high sensitivity (94.3%), while maintaining specificity (69.1%). CONCLUSION: The diagnostic performance of multidetector CT and MR imaging with MRCP for identifying the malignant potential of pancreatic IPMNs was similar and showed good intermodality agreement, suggesting that follow-up with either modality may be used.