Branch Duct Intraductal Papillary Mucinous Neoplasms: Recommendations for Follow-Up and Surgery

Are the screening guidelines for branch duct intraductal papillary mucinous neoplasms cost-effective in an Australian setting?

BACKGROUNDS

Intraductal papillary mucinous neoplasms (IPMN) are cystic neoplasms of the pancreatic ductal system. These incidental cystic lesions are increasingly found on radiological imaging and screened for malignant transformation. The Fukuoka consensus guidelines recommend screening with computed tomography, magnetic resonance imaging or endoscopic ultrasound. Branch duct IPMN (BD-IPMN) have significantly lower malignancy and mortality rates compared to main duct IPMN. Our aim was to assess the cost-effectiveness of guideline's recommendations for BD-IPMN screening of cysts between 2 and 3 cm in an Australian context.

METHODS

Markov model decision analysis was used to calculate the incremental cost-effectiveness ratio (ICER) of screening. The ICER was compared to a willingness to pay (WTP) threshold of $50 000. We performed scenario analysis to examine the effect of cyst size and non-linearity of malignancy rate on ICER. Probabilistic sensitivity analyses (PSA) were performed on our input parameters.

RESULTS

Screening resulted in 586 quality adjusted life years gained and a net present value of $20 379 939, resulting in a base-case ICER of $34 758. After scenario analysis for non-linearity of malignancy rate the ICER increases to $64 555, which is above the WTP threshold. PSA indicates that ICER is most susceptible to the pre-test malignancy rate.

CONCLUSION

This cost analysis demonstrates that screening of 2-3 cm BD-IPMN according to current guidelines is unlikely to be cost-effective in an Australian context. To determine the true ICER, a cost analysis on real-world data is required.

Nomogram to predict malignancy in branch duct type intraductal papillary mucinous neoplasms

Prediction of malignancy in branch duct (BD)-type intraductal papillary mucinous neoplasms (BD-IPMNs) is difficult. In this retrospective study, we showed the performance of imaging biomarker and biochemical biomarker in identifying the malignant BD-IPMNs. A total of 97 patients with pathological proved BD-IPMNs were included in this study. Imaging data were collected from magnetic resonance imaging (MRI). Malignant BD-IPMNs were defined as those with high grade dysplasia and invasive carcinoma. There were 10 patients with malignant BD-IPMNs (10.3%). Significant difference was found in prevalence of mural nodule and tumor size >3.0 cm between patients with and without malignant BD-IPMNs (44.4% vs 3.1%, P < .01; 80.0% vs 33.3%, P < .01). Significant differences were observed in mural nodule and elevated carbohydrate antigen 19-9 (CA19-9) between patients with and without invasive carcinoma (40.0% vs 7.6, P = .05; 60% vs 15.3%, P = .04). Mural nodule and tumor size >3.0 cm were the independent associated factor for malignant BD-IPMNs. The odds ratio (OR) was 5.22 (95% confidence interval [CI]: 1.04-31.16) for mural nodule and was 6.80 (95% CI: 1.16-39.71) for cyst size >3.0 cm. The combined model of mural nodule and tumor size showed good performance in identifying malignant BD-IPMNs (area under the curve [AUC] = 0.82, 95%CI: 0.67-0.97). Our data show that mural nodule and cystic size can be used as predictor of malignancy in BD-IPMN. The predictive performance is acceptable.

A retrospective study of intraductal papillary neoplasia of the pancreas (IPMN) under surveillance

BACKGROUND AND OBJECTIVE

The growing number of identified intraductal papillary mucinous neoplasm (IPMN) patients places greater pressure on healthcare systems. Only a minority of patients have IPMN-related symptoms. Thus, more precise surveillance is required.

METHODS

In this retrospective single-center cross-sectional study, patients with an active diagnosis of branch duct IPMN (BD-IPMN) and >6 months of surveillance were classified as follows: presence/absence of worrisome features (WF) or high-risk stigmata (HRS), newly developed WF/HRS, under/over 15 mm cyst, growing/not growing <15 mm cyst, and elevated serum carbohydrate antigen 19-9 (CA 19-9).

RESULTS

In all, 377 patients with BD-IPMN were followed for a median of 5.4 years, 28% with WF at diagnosis, and 14% who developed WF/HRS during surveillance. Half had a <15 mm primary cyst, 40% of which did not grow during surveillance. CA 19-9 was elevated in 12%. None of the patients with normal CA 19-9 levels developed cancer or high-grade dysplasia (HGD).

CONCLUSIONS

No carcinomas or HGDs appeared with normal CA 19-9 levels. Patients with <15 mm cysts that do not grow and have no WF/HRS could undergo imaging less frequently.

[Intraductal neoplasms of the pancreas]

The latest WHO classification of tumors of the digestive system (2019) has introduced new concepts for the stratification of intraductal neoplasms of the pancreas, mostly based on molecular genetics and malignant potential. Among them, pancreatic intraepithelial neoplasias (PanINs) and intraductal papillary mucinous neoplasms (IPMN) are both precursors of pancreatic ductal adenocarcinoma, whereas intraductal oncocytic papillary neoplasms (IOPN) and intraductal tubulopapillary neoplasms (ITPN) are usually associated with less aggressive subtypes of pancreatic cancer and therefore have a much better prognosis. Hence, it is of utmost importance to correctly classify these lesions and to distinguish them from each other as well as from other nonductal types of neoplasms, which can rarely display an intraductal growth, such as neuroendocrine tumors and acinar cell carcinomas. PanIN are microscopic lesions with limited clinical significance. In contrast, all other intraductal neoplasms can be identified as cystic processes and/or solid tumors by means of imaging, thereby setting an indication for a potential surgical resection. This review presents diagnostically relevant aspects of intraductal neoplasms of the pancreas, which are instrumental for the discussion within interdisciplinary tumor boards (resection vs. watch-and-wait strategies) as well as to determine the extent of resection intraoperatively.