Predictors of early stages of histological progression of branch duct IPMN

Systematic review and meta-analysis of observational studies on BD-IPMNS progression to malignancy

BACKGROUND

The vast majority of presumed branch-duct intraductal papillary mucinous neoplasms (BD-IPMNs) of the pancreas are referred to a surveillance program due to the relatively low risk of malignancy. We aim to evaluate all available data from observational studies focused on the risks of BD-IPMN progression and malignancy to provide vital insights into its management in clinical practice.

METHODS

A comprehensive search was conducted at PubMed, Cochrane, Web of Science and Embase for observational studies published before January 1st, 2020. The progression of BD-IPMN was defined as the development of worrisome features (WFs) or high-risk stigmata (HRS) during surveillance. Overall malignancy was defined as all malignancies, such as malignant IPMN, concomitant pancreatic ductal adenocarcinoma (PDAC) and other malignancies, including BD-IPMN with high-grade sec. Baltimore consensus 2015 or BD-IPMN with high-grade dysplasia (carcinoma in situ) sec. WHO 2010. A meta-analysis was performed to investigate the presence of a mural nodule as a possible predictor of malignancy.

RESULTS

Twenty-four studies were included, with a total of 8941 patients with a presumed BD-IPMN. The progression rate was 20.2%, and 11.8% underwent surgery, 29.5% of whom showed malignancy at the final pathology. Of those, 78% had malignant IPMNs, and 22% had concomitant pancreatic cancer. Overall, 0.5% had distant metastasis. The meta-analysis showed that the risk of malignancy in the presence of a mural nodule >5 mm had a RR of 5.457 (95% CI 1.404-21.353), while a nonenhancing mural nodule or an enhancing mural nodule < 5 mm had a RR of 5.286 (95% CI 1.805-15.481) of harboring malignancy.

CONCLUSION

Most presumed BD-IPMNs entering surveillance do not become malignant. Of those submitted to surgery, concomitant PDAC adds to the overall risk of detecting malignancy.

Systematic review, meta-analysis, and a high-volume center experience supporting the new role of mural nodules proposed by the updated 2017 international guidelines on IPMN of the pancreas

BACKGROUND

Mural nodules (MNs) have a predominant role in the 2016 revision of the international guidelines on intraductal papillary mucinous neoplasms (IPMN) of the pancreas. The aim of this study was to evaluate MNs as predictors of invasive cancer (iCa) or high-grade dysplasia (HGD) in IPMNs and to investigate the role of MN size in risk prediction.

METHODS

A PRISMA-compliant systematic review of the literature and meta-analysis on selected studies were conducted. The random effect model was adopted, and the pooled SMD (standardized mean difference) obtained. The surgical series of IPMNs at a single high-volume institution was reviewed.

RESULTS

This review included 70 studies and 2297 resected IPMNs. MNs have a positive predictive value for malignancy of 62.2%. The meta-analysis suggested that MN size has a considerable effect on predicting IPMNs with both iCa or HGD with a mean SMD of 0.79. All studies included in the meta-analysis used contrast-enhanced endosonography (CE-EUS) to assess MNs. Due to the heterogeneity of the proposed thresholds, no reliable MN size cut-off was identified. Of 317 IPMNs resected at our institution, 102 (32.1%) had a preoperative diagnosis of MN. Multivariate analysis showed that MN is the only independent predictor of iCa and HGD for all types of IPMNs.

CONCLUSION

MNs are reliable predictors of iCa and HGD in IPMNs as proposed by the 2016 IAP guidelines. CE-EUS seems to be the best tool for characterizing size and has the best accuracy for predicting malignancy. Further studies should determine potential MN dimensional cut-offs.

Predictive performance of factors associated with malignancy in intraductal papillary mucinous neoplasia of the pancreas

Background

Estimation of the risk of malignancy in intraductal papillary mucinous neoplasia (IPMN) of the pancreas is a clinical challenge. Several routinely used clinical factors form the basis of the current consensus guidelines. This study aimed to determine the predictive values of the most commonly assessed risk factors.

Methods

A meta-analysis of individual risk factors of malignancy in IPMN was performed. Contingency tables were derived from these data, and sensitivity, specificity, negative and positive predictive values, and diagnostic odds ratios (DOR) were determined. Hierarchical summary receiver operating characteristic (HSROC) curves for each factor were calculated and the respective area under the curve (AUC) was assessed.

Results

A total of 3443 studies were screened initially. Analysis of recent literature revealed 60 studies with 13 relevant risk factors including clinical, serological and radiological parameters. The largest area under the HSROC curve was found for weight loss (0·84) and jaundice/raised bilirubin level (0·80), followed by increased carcinoembryonic antigen (CEA) (0·79) or carbohydrate antigen (CA) 19-9 (0·78) levels. The most sensitive factors were patient age (71 per cent) and mural nodules (65 per cent), and jaundice/raised bilirubin level (97 per cent) and increased CEA level (95 per cent) were most specific. None of the analysed factors reached a positive or negative level of prediction beyond 90 per cent.

Conclusion

None of the established criteria safely distinguishes malignant from non-malignant lesions.