Combining radiomic features with a miRNA classifier may improve prediction of malignant pathology for pancreatic intraductal papillary mucinous neoplasms

Intraductal papillary mucinous neoplasms (IPMNs) are pancreatic cancer precursors incidentally discovered by cross-sectional imaging. Consensus guidelines for IPMN management rely on standard radiologic features to predict pathology, but they lack accuracy. Using a retrospective cohort of 38 surgically-resected, pathologically-confirmed IPMNs (20 benign; 18 malignant) with preoperative computed tomography (CT) images and matched plasma-based ‘miRNA genomic classifier (MGC)’ data, we determined whether quantitative ‘radiomic’ CT features (+/- the MGC) can more accurately predict IPMN pathology than standard radiologic features ‘high-risk’ or ‘worrisome’ for malignancy. Logistic regression, principal component analyses, and cross-validation were used to examine associations. Sensitivity, specificity, positive and negative predictive value (PPV, NPV) were estimated. The MGC, ‘high-risk,’ and ‘worrisome’ radiologic features had area under the receiver operating characteristic curve (AUC) values of 0.83, 0.84, and 0.54, respectively. Fourteen radiomic features differentiated malignant from benign IPMNs (p<0.05) and collectively had an AUC=0.77. Combining radiomic features with the MGC revealed an AUC=0.92 and superior sensitivity (83%), specificity (89%), PPV (88%), and NPV (85%) than other models. Evaluation of uncertainty by 10-fold cross-validation retained an AUC>0.80 (0.87 (95% CI:0.84-0.89)). This proof-of-concept study suggests a noninvasive radiogenomic approach may more accurately predict IPMN pathology than ‘worrisome’ radiologic features considered in consensus guidelines.

Case report: Irreversible electroporation for locally advanced pancreatic cancer

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Locally advanced pancreas cancer (LAPC) has minimal options for local control.

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Irreversible electroporation (IRE) can potentially improve local control for LAPC.

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We present a case of IRE with literature review and risks and benefits of IRE.

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Future studies are needed to clarify which patients may benefit most from IRE.

Introduction

For patients with pancreatic adenocarcinoma who are not candidates for surgical resection, long-term survival is poor, even with currently available systemic and radiation therapy options. However, for those with locally advanced disease who do not have distant metastasis, locoregional control of the tumor has the potential to improve long-term outcomes. A newly developed technology, irreversible electroporation, has advantages over traditional thermal ablation with unresectable cancers in this location.

Presentation of case

In our case report, we describe the first patient treated with irreversible electroporation at our institution for locally advanced pancreatic cancer. The patient is a 63-year-old man who had a partial response to standard chemotherapy and radiation, but was found on operative assessment to have persistently unresectable disease. He therefore underwent irreversible electroporation to the pancreatic mass. His postoperative course was complicated by delayed gastric emptying and wound infection. Three months after surgery, he had no evidence of distant or recurrent disease.

Discussion

Irreversible electroporation for locally advanced pancreatic cancer is an emerging technique which attempts to improve local control of locally advanced, non-metastatic pancreatic cancer. Early data have demonstrated the potential for improved long-term survival in these patients, although further studies are needed to confirm safety and efficacy of this technique.

Conclusion

While there is a positive outlook for the use of irreversible electroporation for locally advanced pancreas cancer, there remain some uncertainties surrounding this therapy, which underscores the importance of future research in this area.

Abstract 970A: Using a radiogenomic approach to classify pancreatic cancer precursors

Background: Intraductal papillary mucinous neoplasms (IPMNs) are cystic pancreatic cancer precursors incidentally detected by imaging in more than 75,000 Americans each year. There is an unmet need to discover noninvasive approaches to differentiate ‘benign’ IPMNs that can be monitored from ‘malignant’ IPMNs that warrant surgery. We previously developed a blood-based ‘miRNA genomic classifier (MGC)’ that helps predict malignant IPMN pathology. The goal of this study was to evaluate whether novel radiomic features from preoperative computed tomography (CT) scans may improve prediction of IPMN pathology beyond that provided by standard radiologic features, either alone or in combination with the MGC.

Methods: Preoperative CT images were obtained for 37 surgically-resected, pathologically-confirmed IPMN cases with matched preoperative miRNA expression data. Images were reviewed for standard radiologic features characterized to be ‘high-risk’ or ‘worrisome’ for malignancy according to consensus guidelines. The region of interest within the pancreas was identified and segmented using a semi-automated algorithm. A total of 112 two-dimensional (2D) quantitative texture features (which measure tumor size, shape, and location) and non-texture features (which measure smoothness, coarseness, and regularity) were extracted. Logistic regression models were used to explore associations between non-redundant radiomic features and IPMN pathology. Principal component analysis was also performed to generate an index score (defined by the first principal component of the most promising radiomic features) that was evaluated for its association with malignant pathology. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of the new radiomic features individually and in combination with the MGC were estimated and compared to values obtained for standard radiologic features.

Results: The MGC and standard ‘high-risk’ and ‘worrisome’ radiologic features had area under the receiver operating characteristic curve (AUC) values of 0.83, 0.84, and 0.54, respectively. Analysis of 112 extracted preoperative radiomic CT features revealed 14 textural and non-textural features that differentiated malignant from benign IPMNs (P&lt;0.05). Collectively, the 14 radiomic features had an AUC = 0.77. A model that combined radiomic features and the MGC had an AUC = 0.92 and estimates of sensitivity (83%), specificity (89%), PPV (88%), and NPV (85%) that were superior to models not based on these novel data types.

Conclusions: Our preliminary findings suggest that clinical decision-making models that integrate novel quantitative radiomic features with a blood-based miRNA classifier may more accurately predict IPMN pathology than models that rely on standard clinical data or worrisome radiologic features alone. Larger, prospective, multi-center studies are planned to explore this topic further.

Citation Format: Jennifer B. Permuth, Jung Choi, Yoganand Balarunathan, Jongphil Kim, Dung-Tsa Chen, Kun Jiang, Sonia Orcutt, Lu Chen, Kimberly Quinn, Rodrigo Carvajal, Guillermo Gonzalez-Calderon, Michelle Fournier, Mahmoud Abdalla, Alberto Garcia, Amber Bouton, Danny Yakoub, Suzanne Lechner, Jose Trevino, Nipun Merchant, Robert Gillies, Mokenge Malafa. Using a radiogenomic approach to classify pancreatic cancer precursors. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 970A.

Impact of postoperative nadir hemoglobin and blood transfusion on outcomes after operations for atherosclerotic vascular disease

OBJECTIVE

Controversy surrounds the topic of transfusion policy after noncardiac operations. This study assessed the combined impact of postoperative nadir hemoglobin (nHb) levels and blood transfusion on adverse events after open surgical intervention in patients who undergo operative intervention for atherosclerotic vascular disease.

METHODS

Consecutive patients who underwent peripheral arterial disease (PAD)-related operations were balanced on baseline characteristics by inverse weighting on propensity score calculated as their probability to have nHb greater than 10 gm/dL on the basis of operation type, demographics, and comorbidities, including the revised cardiac risk index. A multivariate generalized estimating equation analysis was performed to investigate associations between nHb, transfusion, and a composite outcome of perioperative death and myocardial infarction. Logistic and Cox proportional hazards regressions were used to assess the impact of nHb and transfusion on respiratory and wound complications; and a composite end point (CE) of death, myocardial infarction during a 2-year follow-up. Level of statistical significance was set at alpha of 0.0125 to adjust for the increased probability of type I error attributable to multiple comparisons.

RESULTS

The analysis cohort included 880 patients (1074 operations). After adjusting for nHb level, the number of units transfused was not associated with the perioperative occurrence of the CE (odds ratio [OR], 1.13; P = .025). Adjusted for the number of units transfused, nHb had no impact on the perioperative CE (OR, 0.62; P = .22). An interaction term between transfusion and nHb level remained nonsignificant (P = .312), indicating that the impact of blood transfusion was the same regardless of the nHb level. Perioperative respiratory complications were more likely in patients receiving transfusions (OR, 1.22; P = .009), and perioperative wound infections were less common in patients with nHb >10 gm/dL (OR, 0.65; P = .01). During an average follow-up of 24 months, transfused patients were more likely to develop the CE (hazard ratio [HR], 1.15, P = .009), whereas nHb level did not impact the long-term adverse event rate (HR, 0.78; P = .373). The above associations persisted even after adjusting the Cox regression model for the occurrence of perioperative cardiac events.

CONCLUSIONS

Although nHb less than 10 gm/dL is not associated with death or ACS after PAD-related operations, maintaining nHb greater than 10 gm/dL appears to decrease the risk of wound infection. Blood transfusion is associated with increased risk of perioperative respiratory complications. Until a randomized trial settles this issue definitively, a restrictive transfusion strategy is justified in patients undergoing operations for atherosclerotic vascular disease.