Difference in Clinical Behavior of the Pancreatic Adenocarcinomas versus Pancreatic Neuroendocrine Tumors (PNETs) - A Systematic Review and Meta-Analysis

Abstract

Introduction: The pancreatic adenocarcinomas and pancreatic neuroendocrine tumors (PNETs) are two distinct type of cancers and it is critical to understand the difference in clinical course, diagnostic and treatment patterns. This study aims to determine the difference in clinical behavior of pancreatic adenocarcinoma vs PNETs. Methods: A comprehensive literature search was performed using different search engines. A total of 26 studies on adenocarcinoma and 53 studies on PNET were included in the analysis. The information extracted was only focused on the variables describing clinical behavior (signs or symptoms). The weighted mean estimates with corresponding 95% confidence intervals were obtained between the adeno and non-adeno groups separately, along with each study within the two groups. Mean differences were also obtained across the corresponding variables. SAS version 9.4 was used. Results: A total of 5493 patients were identified with 4373 having adenocarcinoma. The weighted percentage was reported for age, gender, anatomical location and cancer subtypes as shown in Figure. 1. Comparison of the most common manifestations:: As seen in Figure 2A, the top 9 most common manifestations are described for each particular category of cancer. The abdominal pain was the most common variable reported in both categories. Comparison of the overlapping common manifestations: Among the nine most common symptoms, adenocarcinoma and PNET overlapped in the 4 manifestations as shown in 2B. The average mean difference was reported to compare the rate of different variables as seen in table.1. PNETs category was found to have more percentage of males, smoking, the location of the tumor in body and tail, weight loss, diarrhea, diarrhea, and fever. Similarly, adenocarcinoma was associated with more female population, tumor location in the head, abdominal pain, jaundice, fatigue, anemia, and nausea.107_A Figure 1. Age, gender, anatomical location and classification of pancreatic cancer in the literature.107_B Figure 2. Top 9 signs and symptoms. Figure 2B: Comparison between the common manifestations in adenocarcinoma and PNETPNETs subtypes manifestation: Based on the analyses of specific PNET subtypes, we found the most frequently reported manifestations by reported prevalence are: weight loss in Glucagonoma (74.19%), weight gain in Insulinoma (36.71%), diarrhea in VIPoma (100%), abdominal pain in somatostatinoma (45.45%), ZES (75.50%) and nonfunctional tumor (40.00%). Conclusion: The clinical manifestations vary depending upon the type of pancreatic cancer. Our study results will help decipher the clinical pattern of the particular type of pancreatic cancer. However, studies need to be done to further delineate the exact pattern.107_C Figure 3. Differences between Non-Adenocarcinoma vs Adenocarcinoma