Endoscopic ultrasonography-guided fine-needle aspiration cytology of surgically confirmed cystic pancreatic neuroendocrine tumors: a Mayo Clinic experience

Endoscopic Ultrasound-Guided Fine Needle Acquisition for Evaluation of Pancreatic Neuroendocrine Tumors: A Meta-Analysis

AIMS

The aim of this meta-analysis was to assess the diagnostic performance of EUS-FNA/B in patients with panNETs.

METHODS

We conducted a computerized search of the MEDLINE and Embase databases to identify relevant articles. The primary outcomes involved grading concordance rate, diagnostic rate, and correlation coefficient (Cohen's κ) for FNA/B samples compared with surgical specimens. Secondary outcomes included sample adequacy, mean number of passes, and adverse events.

RESULTS

Forty-five studies involving 2978 patients were finally included. The pooled concordance rate between EUS-FNA/B and surgical grading was 0.77 (95% CI: 0.73-0.80; I2=48.2%). A significantly higher level of concordance was observed in G1 subgroup (0.88, 95% CI: 0.84-0.91), whereas the G2 subgroup revealed the lowest level of agreement (0.59, 95% CI: 0.52-0.65; P < 0.001). Pooled diagnostic rate for FNA/B sampling was 0.83 (95% CI: 0.79-0.86; I2=63.3%). In addition, FNB outperformed FNA in terms of sample adequacy (0.93 for FNB vs. 0.81 for FNA; P=0.007) and number of needle passes required (2.53 for FNB vs. 3.32 for FNA; P=0.013). Moreover, the overall level of agreement for grading was moderate (κ=0.59, 95% CI: 0.49-0.68; I2=84.5%). There were a limited number of adverse events that had minor influence on patient outcomes (0.03, 95% CI: 0.02-0.05; I2=19.2%).

CONCLUSIONS

EUS-FNA/B is a reliable approach for the diagnosis and preoperative grading of panNET, with FNB demonstrating superior performance compared with FNA.

Diagnostic Concordance of Cytology and Histology in Samples Obtained via Endoscopic Ultrasound-Guided Fine-Needle Biopsy (EUS-FNB)

Introduction Endoscopic ultrasound (EUS)-guided fine-needle aspiration and biopsy (FNA/FNB) to obtain cytological aspirates and histological core samples, respectively, are the standard of care for diagnosing lesions in/adjacent to the upper/lower gastrointestinal tract. Due to the lack of standardization of tissue processing, it is unclear whether core samples should be sent only for histology (formalin) or cytology (CytoLyt), or both. The aim of this study was to investigate the diagnostic concordance rates between cytology and histology on EUS-FNB core samples. Methods A total of 227 patients underwent EUS-FNB between October-2017 and February-2019 by a single therapeutic endoscopist; 44 core-tissue samples (41 patients) were placed alternately in CytoLyt (cytology) and formalin (histology), with equal passes into each, to best achieve a proportionate sample amount. The patient's demographics, medical history, pertinent imaging, EUS indication/findings were reviewed. Main outcomes included concordance rates between cytology-histology and diagnostic accuracy for malignancy. Results Cytology and histology were discordant in five cases (11.5%); four with negative cytology but a definite diagnosis of malignancy achieved with histology. One case was suspected as neoplasm on cytology but further characterized as benign on histology. Cytology failed to sub-characterize an additional four mass-like pancreatic benign entities, due to inadequate tissue architecture assessment in the CytoLyt sample. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of cytology for diagnosis of malignancy were 87.88% (95%CI: 71.8-96.6), 90.91% (95%CI: 58.7-99.7), 96.67% (95%CI: 81.6-99.4), and 71.43% (95%CI: 49.4-86.4). Discussion We observed 11.5% diagnostic discordance between cytology and histology on EUS-FNB core samples, with histology being superior. Future multicenter prospective randomized studies are needed to establish an accurate and cost-effective diagnostic process.

A single-center experience with pancreatic cystic neuroendocrine tumors

BACKGROUND

Pancreatic neuroendocrine tumors (PNET) are rare, with a significant malignant potential. This study aimed to determine outcomes of patients with resected PNETs according to the cystic component and confirm the accuracy of preoperative staging.

METHODS

From 1997 to 2016, 106 patients underwent resection of PNETs, including 73 purely solid (S-PNETs, 69%), 21 mixed (M-PNETs, 20%), and 12 purely cystic lesions (C-PNETs, 11%). To ensure consistent comparisons of overall (OS) and disease-free (DFS) survival outcomes between the 3 groups, the patients were matched according to the World Health Organization (WHO) grade and tumor height.

RESULTS

Overall, the rate of correlation between the preoperative and pathological diagnoses was low in the C-PNET group (33%, P = 0.03). None of the 24 patients (23%) with metastatic disease at the time of surgery were in the C-PNET group. Furthermore, significantly more parenchyma-sparing resections (P = 0.039) and fewer enlarged resections (P = 0.019) were achieved in the C-PNET group. C-PNET group had a significantly lower node invasion rate than the S-PNET and M-PNET groups (8% vs. 41% and 24%, P = 0.004). Although median OS was comparable in all 3 groups before (P = 0.3) and after (P = 0.18) matching, higher median DFS was observed in the C-PNET group than in the other groups after matching (P = 0.038).

CONCLUSION

C-PNET was associated with a better prognosis than PNET with a solid component. The results support a wait-and-see policy in cases wherein a reliable preoperative diagnosis remains challenging.

Endoscopic ultrasound-guided sampling of solid pancreatic masses: the fine needle aspiration or fine needle biopsy dilemma. Is the best needle yet to come?

Fine needle aspiration (FNA) is currently the standard of care for sampling pancreatic solid masses by using endoscopic ultrasound (EUS). The accuracy of the technique is reported to be high, especially if coupled with the rapid on site evaluation (ROSE), and it has a high safety profile. However, FNA presents some limitations, such as the small amount of tissue that can be collected and the inability of obtaining a core tissue with intact histological architecture, which is relevant to perform immunohistochemical analysis, molecular profiling and, therefore, targeted therapies. Moreover, the presence of the ROSE by an expert cytopathologist is very important to maximize the diagnostic yield of FNA technique; however, it is not widely available, especially in small centers. Hence, the introduction of EUS fine needle biopsy (FNB) with a new generation of needles, which show a high safety profile too and a satisfying diagnostic accuracy even in the absence of ROSE, could be the key to overcome the limitations of FNA. However, FNB has not yet shown diagnostic superiority over FNA. Considering all the technical aspects of FNA and FNB, the different types of needle currently available, comparisons in term of diagnostic yield, and the different techniques of sampling, a tailored approach should be used in order to determine the needle that is most appropriate for the different specific scenarios.

Clinicopathological characteristics of non-functioning cystic pancreatic neuroendocrine tumors

BACKGROUND/OBJECTIVES

The biological features of cystic pancreatic neuroendocrine tumors (PNETs) remain unclear. The aim of this study was to clarify the clinicopathological characteristics of non-functioning PNETs (NF-PNETs) with a cystic component.

METHODS

The medical records of 75 patients with NF-PNETs who had undergone resection in our institution were retrospectively reviewed. Clinicopathological factors were compared between PNETs with and without a cystic component. Expression of somatostatin 2 receptor (SSTR-2) was also analyzed.

RESULTS

Cystic PNETs were diagnosed in 14 patients (19%). The proportion of men was significantly higher for cystic than solid PNETs (79% vs. 44%, P < 0.05) and cystic PNETs were significantly larger than solid PNETs (25 mm vs. 17 mm, P < 0.01). However, there were no significant differences in the prevalence of lymph node metastases (14% vs. 10%, P = 0.64), hepatic metastasis (7% vs. 3%, P = 0.54), or disease-free survival rate (both 86%, P = 0.29) between PNETs with and without a cystic component. SSTR-2 expression was more frequently observed in PNETs with a cystic component than in those without (100% vs. 70%, P < 0.01).

CONCLUSIONS

Although cystic PNETs were larger upon diagnosis than solid PNETs in this study, prognosis after surgical resection did not differ significantly between these types of PNET. Somatostatin receptor scintigraphy and somatostatin analogues may be more useful for diagnosing and treating cystic PNETs, respectively.

Cystic pancreatic neuroendocrine tumors (cPNETs): a systematic review and meta-analysis of case series

Cystic pancreatic neuroendocrine tumors represent 13% of all neuroendocrine tumors. The aim of this study is to analyze the phenotype and biologic behavior of resected cystic neuroendocrine tumors. A systematic review and meta-analysis were conducted until September 2016 using a search in Medline, Scopus, and EMBASE with the terms "cystic pancreatic endocrine neoplasm", "cystic islets tumors" and "cystic islets neoplasms". From the 795 citations recovered 80 studies reporting on 431 patients were selected. 87.1% (n = 387) were sporadic tumors and 10.3% (n = 40) corresponded to multiple endocrine neoplasia endocrine type 1. Were diagnosed incidentally 44.6% (n = 135). Cytology was found to have a sensitivity of 78.5%. Were non-functional tumors 85% (n = 338), and among the functional tumors, insulinoma was the most frequent. According to the European Neuroendocrine Tumor Society staging, 87.8% were limited to the pancreas (I-IIb), and 12.2% were advanced (III-IV). Disease-free survival at 5 years in stages (I-IIIa) and (IIIb-IV) was 91.5% and 54.2%, respectively; and was significantly lower (p = 0.0001) in functional tumors. In patients with multiple endocrine neoplasia there was a higher incidence of functional (62.5%) and multifocal (28.1%) tumors. Disease-free survival at 5 and 10 years was 60%. Cystic pancreatic neuroendocrine tumors exhibit phenotypical characteristics which are different to those of solid neuroendocrine tumors.

Neuroendocrine tumors of the pancreas: Degree of cystic component predicts prognosis

BACKGROUND

Although most pancreatic neuroendocrine tumors are solid, approximately 10% are cystic. Some studies have suggested that cystic pancreatic neuroendocrine tumors are associated with a more favorable prognosis.

METHODS

A retrospective review of all patients with pancreatic neuroendocrine tumors who underwent operative resection between 1999 and 2014 at a single academic medical center was performed. Based on cross-sectional imaging performed before operation, pancreatic neuroendocrine tumors were classified according to the size of the cystic component relative to the total tumor size: purely cystic (100%), mostly cystic (≥50%), mostly solid (<50%), and purely solid (0%). Clinicopathologic characteristics and recurrence-free survival were assessed between groups.

RESULTS

In the study, 214 patients met inclusion criteria: 8 with purely cystic tumors, 7 with mostly cystic tumors, 15 with mostly solid tumors, and 184 with purely solid tumors. The groups differed in terms of tumor size (1.5 ± 0.5, 3.0 ± 1.7, 3.7 ± 2.6, and 4.0 ± 3.5 cm), lymph node positivity (0%, 0%, 26.7%, and 34.2%), intermediate or high grade (0%, 16.7%, 20.0%, and 31.0%), synchronous liver metastases (0%, 14.3%, 20.0%, and 26.6%) and need for pancreaticoduodenectomy (0%, 0%, 6.7%, and 25.0%), respectively. No cases of purely cystic pancreatic neuroendocrine tumors were associated with synchronous liver or lymph node metastasis, intermediate/high grade, recurrence, or death due to disease. Among patients presenting without metastatic disease, 10-year recurrence-free survival was 100% in patients with purely and mostly cystic tumors versus 53.0% in patients with purely and mostly solid tumors; however, this difference did not reach statistical significance.

CONCLUSION

Pancreatic neuroendocrine tumors demonstrate a spectrum of biologic behavior with an increasing cystic component being associated with more favorable clinicopathologic features and prognosis. Purely cystic pancreatic neuroendocrine tumors may represent 1 subset that can be safely observed without immediate resection.