The Role of Needle-Based Confocal Laser Endomicroscopy in the Evaluation of Pancreatic Cystic Lesions: A Systematic Review

The prevalence of pancreatic cystic lesions (PCLs) has increased recently due to the increased use of cross-sectional abdominal imaging and the ageing global population. Current diagnostic techniques are inadequate to distinguish between PCLs that require surgery, close surveillance, or expectant management. This has resulted in increased morbidity from both inappropriately aggressive and conservative management strategies. Needle-based confocal laser endomicroscopy (nCLE) has allowed microscopic examination and visual delineation of the surface epithelium of PCLs. Landmark studies in this decade have correlated nCLE and histological findings and identified characteristics differentiating various types of PCLs. Subsequent studies have confirmed the high diagnostic yield of nCLE and its diagnostic utility in PCLs with an equivocal diagnosis. Moreover, nCLE has been shown to improve the diagnostic yield of PCLs. This will help avoid unnecessary pancreatic surgery, which carries significant morbidity and mortality risks. The early detection of high-grade dysplasia in PCLs will provide early surgical treatment and improve outcomes for pancreatic cancer. Despite the high upfront cost of nCLE, the improved diagnostic accuracy and resultant appropriate management have resulted in improved cost effectiveness. Refining the procedure technique and limiting the procedure length have significantly improved the safety of nCLE. A structured training program and device improvements to allow more complete mapping of the pancreatic cyst epithelium will be crucial for the widespread adoption of this promising technology.

Impact of needle-based confocal laser endomicroscopy on the therapeutic management of single pancreatic cystic lesions

Background and aim

The diagnosis and therapeutic management of large single pancreatic cystic lesions (PCLs) represent major issues for clinicians and essentially rely on endoscopic ultrasound fine-needle aspiration (EUS-FNA) findings. Needle-based confocal laser endomicroscopy (nCLE) has high diagnostic performance for PCLs. This study aimed to evaluate the impact of nCLE on the therapeutic management of patients with single PCLs.

Methods

Retrospective and comparative study. Five independent pancreatic disease experts from tertiary hospitals independently reviewed data from a prospective database of 206 patients with single PCL, larger than 2 cm and who underwent EUS-FNA and nCLE. Two evaluations were performed. The first one included the sequential review of clinical information, EUS report and FNA results. The second one included the same data + nCLE report. Participants had to propose a therapeutic management for each case.

Results

The addition of nCLE to EUS-FNA led to significant changes in therapeutic management for 28% of the patients (p < 0.001). nCLE significantly increased the interobserver agreement of 0.28 (p < 0.0001), from 0.36 (CI 95% 0.33–0.49) to 0.64 (CI 95% 0.61–0.67). nCLE improved the rates of full agreement among the five experts of 24% (p < 0.0001), from 30 to 54%. With nCLE, the surveillance rate of benign SCAs fell by 35%, from 40 (28/70) to 5% (4/76).

Conclusion

The addition of nCLE to EUS-FNA significantly improves reliability of PCL diagnosis and could impact the therapeutic management of patients with single PCLs. ClinicalTrials.gov number, NCT01563133.

Electronic supplementary material

The online version of this article (10.1007/s00464-019-07062-9) contains supplementary material, which is available to authorized users.

Appraisal of needle-based confocal laser endomicroscopy in the diagnosis of pancreatic cysts

Nearly 2.5% of cross-sectional imaging studies will report a finding of a cystic pancreatic lesion. Even though most of these are incidental findings, it remains very concerning for both patients and treating clinicians. Differentiating and predicting malignant transformation in pancreatic cystic lesions is clinically challenging. Current evaluation of suspicious cystic lesions includes a combination of radiologic imaging, endoscopic ultrasound (EUS) and cyst fluid analyses. Despite these attempts, precise diagnostic stratification among non-mucinous, mucinous, and malignant cystic lesions is often not possible until surgical resection. EUS-guided needle based confocal laser endomicroscopy (nCLE) for evaluation of pancreatic cysts is emerging as a powerful technique with remarkable potential. Though limited imaging data from 3 large clinical trials (INSPECT, DETECT and CONTACT) are currently the reference standard for nCLE imaging, nonetheless these have not been validated in large studies. The aim of this review article is to review the evolving role of EUS-guided nCLE in management of pancreatic cystic lesions in terms of its significance, adverse events, limitations, and implications.

In vivo characterization of pancreatic cystic lesions by needle-based confocal laser endomicroscopy (nCLE): proposition of a comprehensive nCLE classification confirmed by an external retrospective evaluation. Surg Endosc. 2016;30:2603-2612. [PMID: 26428198 DOI: 10.1007/s00464-015-4510-5]

BACKGROUND AND AIMS

The differential diagnosis of solitary pancreatic cystic lesions is sometimes difficult. Needle-based confocal laser endomicroscopy (nCLE) performed during endoscopic ultrasound-fine-needle aspiration (EUS-FNA) enables real-time imaging of the internal structure of such cysts. Criteria have already been described for serous cystadenoma and intraductal papillary mucinous neoplasm (IPMN). The aims of the study were to determine new nCLE criteria for the diagnosis of pancreatic cystic lesions, to propose a comprehensive nCLE classification for the characterization of those lesions, and to carry out a first external retrospective validation .

METHODS

Thirty-three patients with a lone pancreatic cystic lesion were included (CONTACT 1 study). EUS-FNA was combined with nCLE. Diagnosis was based on either pathology result (Group 1, n = 20) or an adjudication committee consensus (Group 2, n = 13). Six investigators, unblinded, studied cases from Group 1 and identified nCLE criteria for mucinous cystic neoplasm (MCN), pseudocyst (PC), and cystic neuroendocrine neoplasm (NEN). Four external reviewers assessed, blinded, the yield and interobserver agreement for the newly identified (MCN, PC) and previously described (IPMN, SC) criteria in a subset of 31 cases.

RESULTS

New nCLE criteria were described for MCN (thick gray line), PC (field of bright particles), and cystic NEN (black neoplastic cells clusters with white fibrous areas). These criteria correlated with the histological features of the corresponding lesions. In the retrospective validation, a conclusive nCLE result was obtained for 74 % of the cases (87 % "true" and 13 % "false" with respect to the final diagnosis). On this limited case series, the nCLE criteria showed a trend for high diagnostic specificity (>90 % for mucinous cysts, 100 % for non-mucinous cysts).

CONCLUSIONS

Based on this newly completed atlas of interpretation criteria, nCLE could facilitate the diagnosis of pancreatic cystic lesion types.