Introduction
Pancreatic cyst prevalence is about 2% to 3% in the general population(1,2). It is important to classify them accurately, given the fact that in premalignant lesions surgery could be curative. On the other hand, unnecessary pancreatic surgery could be associated with significant morbidity. The mucinous cysts are considered the premalignant types, traditionally the carcinoembryonic antigen (CEA) has been described as the analysis of cyst fluid to discern them from the non-mucinous. Recently, the cyst glucose value has been described as a better discriminant, however, there are different cut-off levels founds across the studies(3). The distribution of glucose in the body is almost uniform (4), a higher metabolic rate within a cyst translates into lower intracystic glucose, which correlates with high-grade injury (3). Therefore, we decided to explore the diagnostic performance of the glucometry-to-glucometry cyst ratio.
Aims & Methods
We conducted a prospective cohort from January 2021 to October 2022 at the endoscopy department at the National Institute of Medical Sciences and Nutrition “Salvador Zubiran” (INCMNSZ) in Mexico City. We included patients older than 18 years who underwent endoscopic ultrasound with FNA of a pancreatic cyst and had a fluid analysis of glucose, CEA, and amylase. We performed glucometry on-site on the patient and the cyst fluid with a FreeStyle Optium Neo glucometer. Glucometry to glucometry cyst ratio (glucometry patient/glucometry cyst) was calculated for each patient. Follow-up was performed and a final diagnosis was established by a multidisciplinary team, biopsy or surgical specimen. Finally, we performed a 2x2 table and a ROC curve with Youden index to establish the best cut off for diagnostic performance of glucometry-to-glucometry cyst ratio.
Results
24 patients were included 14 with mucinous cyst diagnosis and 10 with non-mucinous diagnosis, the median age was 58.5 (25-84), and 83% were female. CEA mean was 2331.7± 3359.3 ng/mL for mucinous vs 23.8± 62.6 ng/mL for non-mucinous (p= <0.001). The on-site cyst glucometry was 39.3± 22.1mgdL vs 112± 42.9 for the mucinous and non-mucinous respectively (p= 0.001). The glucometry/cyst glucometry relation was 3.30± 0.84 (mucinous) vs 1.13± 0.69 (non-mucinous), p= 0.001. The AUC was 0.971 (0.915 -1.000), 0.948 (0.853 – 1.00), and 0.964 (0.900 – 1.000) for glucose relation, glucometry, and CEA respectively. The sensitivity, specificity, PPV, NPV, and precision for CEA (192ng/dL) was 70%, 92.8%, 87.5%, 81.2%, and 83.3% while glucometry (<50mg/dL) was 80%, 85.7%, 83.3%, 85.7%, and 83.3%. Notably, the glucometry relation (>2.45) found a 90%, 92.8%, 90%, 92.8%, and 91.6% for the same parameters.
Conclusion
The glucometry-to-glucometry cyst relation is a novel, cheap, accessible, and superior diagnostic approach for the classification of mucinous and non-mucinous pancreatic cysts. Further studies with bigger sample sizes are needed to confirm these findings.
References
1. Laffan TA, Horton KM, Klein AP, et al. Prevalence of unsuspected pancreatic cysts on MDCT. AJR Am J Roentgenol 2008;191:802-7.
2. de Jong K, Nio CY, Hermans JJ, et al. High prevalence of pancreatic cysts detected by screening magnetic resonance imaging examinations. Clin Gastroenterol Hepatol 2010;8:806-11
3. Guzman-Calderon E, Md BM, Casellas JA, Aparicio JR. Intracystic Glucose Levels Appear Useful for Diagnosis of Pancreatic Cystic Lesions: A Systematic Review and Meta-Analysis. Dig Dis Sci 2021
4. Zierler K. Whole body glucose metabolism. Am J Physiol 1999;276:E409-26
