ACR Appropriateness Criteria® Pancreatic Cyst

Successful EUS-guided pancreatic cyst chemoablation safely allows reduction in the frequency of radiographic surveillance: long-term follow-up of randomized prospective data

BACKGROUND AND AIMS

Endoscopic ultrasound-guided pancreatic cyst chemoablation is safe and effective for appropriately selected patients; however, the proper frequency of radiographic surveillance after successful chemoablation is unknown. Here we report the long-term follow-up of 2 randomized prospective Chemotherapy for Ablation and Resolution of Mucinous Pancreatic Cysts (ChARM) clinical trials. In addition, the performance of a postablation-reduced radiographic surveillance protocol was evaluated according to clinical and economic outcomes and patient experience metrics.

METHODS

Patients who successfully completed 1 of the 2 ChARM randomized control trials were evaluated for durability of response and clinical outcomes. Patients were eligible if 2 years or more of follow-up were available and complete. We calculated economic outcomes according to Medicare allowable costs applicable to endoscopic ultrasound, magnetic resonance imaging, and outpatient clinic visits. We modeled costs of a patient followed by the ChARM Post-treatment Reduced Radiographic Surveillance Protocol compared with a similar patient followed under Fukuoka or American College of Gastroenterology (ACG) guidelines over 5 years. In addition, patients under long-term surveillance in our clinic were interviewed via a 4-question Likert-type questionnaire.

RESULTS

A total of 52 patients were eligible and included in the study. At the most recent follow-up of the 52 patients, 36 (69.2%) achieved complete response, an additional 11 (21.2%) showed partial response, and only 5 (9.6%) showed nonresponse. All patients were successfully reduced to annual or less surveillance without recurrence or the development of cyst-associated malignancy. Compared with Fukukoa or ACG guidelines, a patient treated and followed under the ChARM Post-treatment Reduced Radiographic Surveillance Protocol incurred a Medicare allowable cost of $7200.00 versus $19,437.44 and $12,526.52 if untreated and observed under Fukukoa and ACG guidelines, respectively. The patient experience questionnaire was returned completed by 49 participants.

CONCLUSIONS

The ChARM Post-treatment Reduced Radiographic Surveillance Protocol safely allows a reduction in radiographic surveillance. A reduction in cost associated with cyst management under the ChARM protocol, compared with management following Fukukoa or ACG guidelines, was shown. According to the questionnaire, most patients reported a moderate level of logistical and emotional burden associated with magnetic resonance imaging surveillance, and a majority were in favor of reducing the frequency of radiographic surveillance if it could be done without a marked increase in oncologic risk.

Pancreatic Cyst Surveillance

Pancreatic cysts (PC) are an increasingly common problem facing general gastroenterologists and generalists. They can be divided into 3 groups. First, those that have no risk of developing into pancreatic cancer, such as a pseudocyst or serous cystadenomas (SCAs). Second, mucinous cystic neoplasms (MCNs) and intraductal papillary mucinous neoplasms (IPMNs), which are precursor lesions to high-grade dysplasia and pancreatic cancer. Third, solid cancers of the pancreas, such as neuroendocrine tumors and pancreatic adenocarcinomas, which have undergone cystic degeneration.

State-of-the-Art Update of Pancreatic Cysts

Andrew Canakis.

Fine-needle aspiration of pancreatic cystic lesions: a randomized study with long-term follow-up comparing standard and flexible needles

BACKGROUND

Pancreatic cystic lesions (PCLs) are increasingly found on cross-sectional imaging, with the majority having a low risk for malignancy. The added value of fine-needle aspiration (FNA) in risk stratification remains unclear. We evaluated the impact of three FNA needles on diagnostic accuracy, clinical management, and the ability to accrue fluid for tumor markers.

METHODS

A multicenter prospective trial randomized 250 patients with PCLs ≥ 13 mm 2:1:1 to 19G Flex, 19G, and 22G needles with crossover for repeated FNA procedures. Diagnostic accuracy was established at 2-year follow-up, with the final diagnosis from surgical histopathology or consensus diagnosis by experts based sequentially on clinical presentation, imaging, and aspirate analysis in blinded review.

RESULTS

Enrolled patients (36 % symptomatic) had PCLs in the head (44 %), body (28 %), and tail (26 %). Percentage of cyst volume aspirated was 78 % (72 % - 84 %) for 19G Flex, 74 % (64 % - 84 %) for 22G, and 73 % (63 % - 83 %) for 19G (P = 0.84). Successful FNA was significantly higher for 19G Flex (89 % [82 % - 94 %]) and 22G (82 % [70 % - 90 %]) compared with 19G (75 % [63 % - 85 %]) (P = 0.02). Repeated FNA was required more frequently in head/uncinate lesions than in body and tail (P < 0.01). Diagnostic accuracy of the cyst aspirate was 84 % (73 % - 91 %) against histopathology at 2-year follow-up (n = 79), and 77 % (70 % - 83 %) against consensus diagnosis among nonsurgical cases (n = 171). Related serious adverse events occurred in 1.2 % (0.2 % - 3.5 %) of patients.

CONCLUSIONS

Our study results demonstrate a statistically significant difference among the three needles in the overall success rate for aspiration, but not in the percentage of cyst volume aspirated. Flexible needles may be particularly valuable in sampling cystic PCLs in the pancreatic head/uncinate process.

An abbreviated MRI protocol for surveillance of cystic pancreatic lesions

PURPOSE

Cystic pancreatic lesions (CPLs) are common and increasingly encountered in clinical radiology practice. The appropriate imaging surveillance strategy for lower-risk CPLs (branch duct-intraductal papillary mucinous neoplasms and indeterminant small cystic lesions) has been a topic of intense study and debate in recent years. MRI is considered the investigation of choice for initial characterisation and follow-up of CPLs. Follow-up intervals for CPLs vary from 6 months to 2 years and surveillance may be lifelong or until the patient is no longer considered fit for potential surgical intervention. This creates a significant burden on MRI resources as a standard protocol pancreatic MRI may have an acquisition time of up to 35-50 min. However, the necessity of contrast-enhanced sequences and diffusion weighted imaging (DWI) for routine follow-up of CPLs has been questioned in recent years.

METHODS

We reviewed the available evidence to determine whether an abbreviated MRI (A-MRI) protocol may be safely adopted for surveillance of CPLs, as has been implemented in other clinical scenarios.

RESULTS

A number of recent retrospective studies have indicated that an A-MRI, omitting contrast-enhanced and DWI, may be used for CPL surveillance without any suspicious features or cases of malignancy being missed. Although small number of cases may need to be recalled for additional MR sequences based on the A-MRI findings, there is still a significant overall timesaving.

CONCLUSION

The best available evidence currently suggests that an A-MRI protocol should be considered for routine surveillance of CPLs. Prospective studies are required to ensure the findings reported in these retrospective case studies are backed up in ongoing clinical practice.

Automated Detection of Pancreatic Cystic Lesions on CT Using Deep Learning

Pancreatic cystic lesions (PCL) are a frequent and underreported incidental finding on CT scans and can transform into neoplasms with devastating consequences. We developed and evaluated an algorithm based on a two-step nnU-Net architecture for automated detection of PCL on CTs. A total of 543 cysts on 221 abdominal CTs were manually segmented in 3D by a radiology resident in consensus with a board-certified radiologist specialized in abdominal radiology. This information was used to train a two-step nnU-Net for detection with the performance assessed depending on lesions' volume and location in comparison to three human readers of varying experience. Mean sensitivity was 78.8 ± 0.1%. The sensitivity was highest for large lesions with 87.8% for cysts ≥220 mm³ and for lesions in the distal pancreas with up to 96.2%. The number of false-positive detections for cysts ≥220 mm³ was 0.1 per case. The algorithm's performance was comparable to human readers. To conclude, automated detection of PCL on CTs is feasible. The proposed model could serve radiologists as a second reading tool. All imaging data and code used in this study are freely available online.

Society of Abdominal Radiology Disease Focused Panel Survey on Clinical Utilization of Incidental Pancreatic Cyst Management Recommendations and Template Reporting

OBJECTIVE

To assess current practice patterns with respect to protocols used for incidental pancreatic cyst follow-up, management guidelines, and template reporting.

METHODS

The Society of Abdominal Radiology Disease Focused Panel on intraductal pancreatic neoplasms distributed an anonymous 14-question survey to its members in June 2018 that focused on current utilization of incidental pancreatic cyst guidelines, protocols, and template reporting.

RESULTS

Among the 1,390 email invitations, 323 responded, and 94.7% (306 of 323) completed all questions. Respondents were mainly radiologists (93.8%, 303 of 323) from academic institutions (74.7%, 227 of 304) in North America (93.7%, 286 of 305). Of respondents, 42.5% (136 of 320) preferred 2017 ACR recommendations, 17.8% (57 of 320) homegrown systems, 15.0% (48 of 320) Fukuoka guidelines, and 7.8% (25 of 320) American Gastroenterological Association guidelines. The majority (68.7%, 222 of 323) agreed or strongly agreed that developing a single international consensus recommendation for management was important, and most radiologists preferred to include them in reports (231 of 322, 71.7%); yet only half included recommendations in >75% of reports (161 of 321). MR cholangiopancreatography was the modality of choice for follow-up of <2.5 cm cysts. Intravenous contrast was routinely used by 69.7% (212 of 304). Standardized reporting templates were rarely used in practice (12.8% 39 of 306).

CONCLUSIONS

Nearly 7 of 10 radiologists desire a unified international consensus recommendation for management of incidental cystic pancreatic lesions; ACR 2017 recommendations are most commonly used, followed by homegrown systems and Fukuoka guidelines. The majority of radiologists routinely use MR cholangiopancreatography with intravenous contrast for follow-up of incidental cystic lesions, but template reporting is rarely used.