Abstract 4: Impact of Immunohistochemistry on Diagnostic Accuracy for Pediatric Cancer in Tanzania

Abstract

Abstract Purpose: The current study evaluates the impact of immunohistochemistry (IHC) on diagnostic accuracy for pediatric cancer in Tanzania, and identifies the most common biomarkers used for diagnostic differentiation in our setting. Methods: Pathology samples for children diagnosed with cancer at Bugando Medical Centre (Mwanza, Tanzania) in 2018 were evaluated using H&E staining. Basic demographic information from histology form was recorded, including patient age, sex, and sample collection, as well as the reported histopathology results from BMC. Additional tissue from histology block was sent to Muhimbili National Hospital for IHC review. The histopathology results were compared for diagnostic agreement, change in diagnosis, and identified which biomarkers were necessary for diagnostic confirmation. Results: One hundred and five (105) pediatric cancer patients were reviewed. 58 (55.2%) were female median age of 6 years (IQR 3-9 years). Most common pediatric diagnoses were Burkitt lymphoma and Non Hodgkin Lymphoma specifically Diffuse Large B-cell lymphoma, anaplastic large cell lymphoma, FL, LL. Overall histology concordance between H&E and IHC was 51.0%. Most common discordant diagnosis was NHL of ALCL (ALK1-negative, CD-45, 30-positivity). Most concordant was Leukemia (BCR-ABL). Diagnostic specificity (example: in Non-Hodgkin Lymphoma) improved for 17.6% (n=18). The most common diagnosis with increased specificity was DLBCL. Among NHL, 39% (n=7) were ALCL, 27% (n=5) DLBCL, 17% (n=3) Lymphoblastic Lymphoma, 17% (n=3) Follicular lymphoma. The use of immunohistochemistry resulted in a change in diagnosis for 31.4% (n=32) of patient. The most common changed diagnosis was Burkitt Lymphoma and Sarcoma. Conclusion: Immunohistochemistry is critically important for accurate diagnosis of pediatric cancer, with over 30% of all cases identified as having treatment changing diagnoses. IHC training is critical and a limited common biomarker panel can successfully be used in low resource countries to improve treatment selection. Citation Format: Jeffer Bhuko, Caroline Minja, Michael McDermott, Maureen Osullivan, Trish Scanlan, Kristin Schroeder. Impact of Immunohistochemistry on Diagnostic Accuracy for Pediatric Cancer in Tanzania [abstract]. In: Proceedings of the 9th Annual Symposium on Global Cancer Research; Global Cancer Research and Control: Looking Back and Charting a Path Forward; 2021 Mar 10-11. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2021;30(7 Suppl):Abstract nr 4.