Clinical Outcomes of Intraductal Papillary Mucinous Neoplasms With Dilatation of the Main Pancreatic Duct

The Revised Kyoto Criteria and Risk of Malignancy Among Patients With Intraductal Papillary Mucinous Neoplasms

BACKGROUND & AIMS

The revised Kyoto guidelines have a new catalog of high-risk stigmata and worrisome features for the risk stratification of intraductal papillary mucinous neoplasms (IPMNs). We aimed to validate the stratification system in terms of short- and long-term risks of pancreatic carcinoma.

METHODS

We included 3336 patients diagnosed with IPMNs in 2000-2021 and examined short-term (≤6 months) and long-term risks of pancreatic carcinoma diagnosis. We used the multivariable competing-risks proportional hazards regression model to calculate subdistribution hazard ratios for long-term incidence of pancreatic carcinoma with adjustment for potential confounders.

RESULTS

In short-term analyses, pancreatic carcinomas were prevalent predominantly in IPMNs with high-risk stigmata (49% vs 1.3% and 0.05% in IPMNs with worrisome features and no risk factors, respectively). In long-term analyses of worrisome features, the main pancreatic duct diameter of 5-9.9 mm, acute pancreatitis, and IPMN growth rate of 2.5 mm/y were associated with a high incidence with multivariable subdistribution hazard ratios of 3.46 (95% confidence interval [CI], 2.04-5.89), 5.65 (95% CI, 1.86-17.2), and 3.83 (95% CI, 2.14-6.86), respectively. An increasing number of worrisome features at baseline was associated with a higher prevalence and incidence of pancreatic carcinoma (Ptrend < .001). Patients with 1, 2, and 3-4 worrisome features had multivariable subdistribution hazard ratios for pancreatic cancer incidence of 1.43 (95% CI, 0.93-2.19), 2.17 (95% CI, 1.17-4.05), and 10.1 (95% CI, 4.20-24.5), respectively (vs no positive feature).

CONCLUSIONS

The revised Kyoto criteria stratify IPMN patients well in terms of the short- and long-term risks of pancreatic carcinoma diagnosis, potentially informing personalized patient management.

Abdominal ultrasound in the characterization of branch-duct intraductal papillary mucinous neoplasms: A new tool for surveillance of low-risk patients?

BACKGROUND

Magnetic resonance imaging (MRI) is regarded as gold-standard for intraductal papillary mucinous neoplasms (IPMNs) follow-up. Given the low risk of transformation and the increasing population under surveillance, there is growing interest in identifying optimal follow-up strategies.

AIM

To evaluate reliability of abdominal ultrasound (US) for characterization of low-risk IPMN, compared to MRI.

METHODS

Prospective monocentric study among 79 consecutive patients with a suspected BD-IPMN on US. Each patient underwent confirmatory MRI. We evaluated Cohen's kappa statistic and concordance rate (CR) between MRI and US.

RESULTS

Of 79 suspected IPMNs on US, MRI confirmed 71 BD-IPMNs. There was high agreement for cyst location and number (CR and kappa of 77.5 % and 81.7 % and 0.66±0.08 and 0.62±0.11 respectively). We found high agreement for cyst size (CR=96.5 %, kappa=0.93±0.05) and main pancreatic duct (MPD) dilatation (CR=100 %, kappa=1). There was a good agreement for thickened septa (CR=80.3 %, kappa=0.38±0.12). US seems inferior to MRI for the identification of mural nodules < 5 mm (CR=97.2 %, kappa=0).

CONCLUSIONS

In a cohort of low-risk BD-IPMN, US presented high agreement rate with MRI regarding location, number, and size. There was a good agreement for MPD dilatation and thickened septa, while US underperform for detection of mural nodules < 5 mm.

Optimal age to discontinue long-term surveillance of intraductal papillary mucinous neoplasms: comparative cost-effectiveness of surveillance by age

OBJECTIVE

Current guidelines recommend long-term image-based surveillance for patients with low-risk intraductal papillary mucinous neoplasms (IPMNs). This simulation study aimed to examine the comparative cost-effectiveness of continued versus discontinued surveillance at different ages and define the optimal age to stop surveillance.

DESIGN

We constructed a Markov model with a lifetime horizon to simulate the clinical course of patients with IPMNs receiving imaging-based surveillance. We calculated incremental cost-effectiveness ratios (ICERs) for continued versus discontinued surveillance at different ages to stop surveillance, stratified by sex and IPMN types (branch-duct vs mixed-type). We determined the optimal age to stop surveillance as the lowest age at which the ICER exceeded the willingness-to-pay threshold of US$100 000 per quality-adjusted life year. To estimate model parameters, we used a clinical cohort of 3000 patients with IPMNs and a national database including 40 166 patients with pancreatic cancer receiving pancreatectomy as well as published data.

RESULTS

In male patients, the optimal age to stop surveillance was 76-78 years irrespective of the IPMN types, compared with 70, 73, 81, and 84 years for female patients with branch-duct IPMNs <20 mm, =20-29 mm, ≥30 mm and mixed-type IPMNs, respectively. The suggested ages became younger according to an increasing level of comorbidities. In cases with high comorbidity burden, the ICERs were above the willingness-to-pay threshold irrespective of sex and the size of branch-duct IPMNs.

CONCLUSIONS

The cost-effectiveness of long-term IPMN surveillance depended on sex, IPMN types, and comorbidity levels, suggesting the potential to personalise patient management from the health economic perspective.

Correlation between main pancreatic duct diameter measurements: Special pancreatic ultrasonography versus magnetic resonance cholangiopancreatography

Main pancreatic duct (MPD) dilatation is reported to be a risk factor for pancreatic cancer (PC). Although magnetic resonance cholangiopancreatography (MRCP) and ultrasonographic modalities are valuable for monitoring the pancreas, there is limited information on the efficacy of different imaging modalities in measuring MPD diameter. To improve pancreatic imaging, we developed a specialized ultrasound approach focusing on the pancreas (special pancreatic US). We aimed to examine the correlation between MPD diameter measurements using special pancreatic US versus MRCP. We retrospectively reviewed the clinical data of patients with MPD dilation (≥2.5 mm) via special pancreatic US used for screening at our institution between January 2020 and October 2022 and included patients who underwent magnetic resonance imaging 2 months before and after pancreatic US. The MPD diameter on MRCP was measured at the pancreatic locus, where the maximum MPD diameter was obtained on special pancreatic US. This study included 96 patients, with a median interval of 8.5 days between the date of special pancreatic US and the date of undergoing MRCP. MPD dilatation and/or pancreatic cysts were diagnosed in 86 patients, PC in 5 patients, and other diseases in 5 patients. The median MPD diameter, measured using special pancreatic US, was 3.4 mm (interquartile range: 2.9-4.9 mm), whereas it was 3.5 mm using MRCP (interquartile range: 2.8-4.5 mm). There were strong positive correlations between MPD diameter measured on special pancreatic US and that measured on MRCP (R = 0.925, P < .001). This study revealed strong positive correlations between the MPD diameter measurements using special pancreatic US and MRCP. MPD diameter measurements from each imaging method can be helpful during follow-up in individuals at a high risk of PC.

Giant dilatation of pancreatic duct associated with congenital anomaly of the pancreatic ductal system and small neuroendocrine tumor

Dilatation of the main pancreatic duct (MPD) ˃50 mm is a rare phenomenon. We present the case of successful surgical treatment a 63-year-old female patient who presented epigastric pain and weight loss of 10 kg in 6 months. Based on preoperative examination, the dilatation of MPD was 75 mm. The preliminary diagnosis was main duct intraductal papillary mucinous neoplasm. Extended pylorus-preserving pancreatoduodenectomy with resection of the body of the pancreas was performed. According to the results of pathological and immunohistochemical studies, performed by independent experts, the final diagnosis of congenital anomaly of the ductal system and neuroendocrine tumor of the accessory pancreatic duct was made.

Co-occurring IPMN and pancreatic cancer: the same or different? An overview from histology to molecular pathology

Intraductal papillary mucinous neoplasm (IPMN) of the pancreas is one of the most well-established precursors of pancreatic cancer. Its progression to acquire invasiveness is a complex process, based on the accumulation of morphological and genetic alterations. Recent advances in DNA sequencing also showed that co-occurring IPMNs and pancreatic cancers could be totally independent, further complicating our understanding of this complex scenario. The distinction between IPMN and related pancreatic cancer vs IPMN and co-occurring-but not related-pancreatic cancer is a challenging task in routine diagnostic activity, but may have important implications for precision oncology. Of note, recent multiregional sequencing-based studies focused not only on IPMN multi-step tumourigenesis, but also on the divergent intratumoural heterogeneity of this neoplasm. Globally considered, there are three different situations in which co-occurring IPMNs and invasive carcinomas can be found in the same pancreata, indicated with different terminologies: (1) IPMN-associated carcinoma: this definition indicates a carcinoma arising from an IPMN and can be also defined as IPMN-derived carcinoma, sequential or likely related; (2) independent IPMN and invasive carcinoma: the two lesions are not related, and this situation is defined as concomitant, de novo or likely independent; (3) branch-off pathway, where an invasive carcinoma and an adjacent IPMN develop divergently in a forked fashion from a common ancestral clone. In this review, we aim at clarifying the most important nomenclature/definitions of these different situations, also providing an overview of the molecular state-of-the-art and of the clinical implications of this complex landscape.