Multiparametric Flow Fytometry Is More Useful Than Cytology As a Diagnostic Tool for Endoscopic and Transbronchial Ultrasound-Guided Fine Needle Aspiration Samples in Hematological Malignancies: A Single Center Experience

INTRODUCTION: Endoscopic and transbrochial ultrasound-guided fine needle aspiration techniques facilitate the sample acquisition process from the deep intrathoracic or intra-abdominal lymph nodes and masses, for cytological analysis, without requiring surgical procedures. These techniques minimize patient's discomfort, are cost-saving and can be applicable as the first diagnostic approach. Accurate analysis of the aspirate material is the key to achieve a correct diagnosis and to conduct further management. The aim of our study is to determine the utility of multiparametric flow cytometry (FC) in comparison to that of cytomorphology (CM) in analyzing samples obtained by endoscopic techniques as screening for hematological malignancies. METHODS: We retrospectively analyzed the results of 166 samples routinely submitted to hematology FC laboratory, obtained by transluminal puncture of adenopathies or masses (124 transbronchial and 42 endoscopic fine needle aspirations) for the screening of hematological neoplasia. All the samples were processed within the first four hours after obtainment. Eight-color, well-standardized panel was used for the screening of lymphoproliferative syndrome (B screening: Kappa-FITC/ Lambda-PE / CD5-PerCP-Cy5.5/ CD19-PE-Cy7/ CD10-APC/ CD38-APCH7/ CD20-V450 /CD45-OC515; and T screening CD2-FITC/ CD5-PE / CD8-PerCP-Cy5.5/ CD7-PE-Cy7/ CD56-APC/ CD4-APCH7/ CD3-V450 /CD45-OC515). At least 1x 10(6) events were acquired by FACSCanto II (BD Biosciences, San Jose, USA). The data was analyzed with the Infinicyt software (Cytognos SL, Spain). Meanwhile, cytomorphology analysis was performed independently by the Pathology department on samples obtained from the same procedure at the same time, with additional immunochemical staining depending on the findings. Finally, results of both techniques were compared to each other and also with the final diagnosis based on the availability of a diagnostic biopsy and the information extracted from clinical history. Statistical analyses were performed using SPSS v20.0 (SPSS Inc., IL USA). RESULTS Comparing the number of evaluable samples using both techniques, FC was more reliable, since 90% (150/166) of the total samples could be evaluated by FC, and only 74% (123/166) were considered evaluable by CM (due to necrosis or hemorrhagic cellularity). Using FC hematological neoplasms were identified in 13% of the total series (22/166): 18 Non Hodgkin lymphoma (NHL) and 4 Multiple Myeloma (MM). In most of the samples (71%; 119/166), the FC approach for screening of lymphoproliferative disorders was negative, and in 9 cases (5%) this approach suggested the presence of a non-hematological neoplasia. Considering CM, although this technique was as useful as FC for the identification of plasma cell dyscrasia identification (4 MM cases detected), it was less useful for NHL diagnosis, detecting only 33% (6/18) of the total number of NHL cases that had been detected by FC. However, CM was more useful for the identification of Hodgkin's Lymphoma (3%; 5/166) and non-hematological neoplasms (14% of carcinomas; 24/166), being the rest of the evaluable samples classified as inflammatory yield (50%; 84/166). In order to reach the definitive final diagnosis, in 66 cases (40%; 66/166) another procedure involving surgery (n= 55) or needle biopsy (n=11) was performed. Eleven new NHL cases were identified, and 8 of these 11 cases were considered as not evaluable for the FC analysis performed in the previous sample, due to low cell viability. In addition, 5 new HL and 10 new carcinoma cases were identified, not diagnosed in previous FNA Cytology. CONCLUSION: Our study of showed that multiparametric FC is more sensitive than CM to diagnose of NHL, while CM is more useful to diagnose solid neoplasms in the analysis of the samples obtained from endoscopic and transbrochial ultrasound-guided FNA technique. Therefore, both techniques should be considered as complementary for the evaluation of these deep thoracic and abdominal nodes or masses. In addition, around 40% of cases require a new biopsy to reach definitive diagnosis. Disclosures Martín: Sevier: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria; Gilead: Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees. Del Cañizo:Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Jansen-Cilag: Membership on an entity's Board of Directors or advisory committees, Research Funding; Arry: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding.