Incidence of and factors associated with discordant pathologic diagnosis in patients with suspected Burkitt Lymphoma treated in a low-resource setting

Abstract

Aim: To determine the frequency of discordant diagnosis of endemic Burkitt Lymphoma at the Uganda Cancer institute and to evaluate different baseline patient characteristics for their association with discordance and its impact on one year overall survival Background: Burkitt Lymphoma is the most common childhood malignancy in many countries of Sub-Saharan Africa. Overall survival rates for this disease in low-resource settings are far below those seen for a similar disease in more affluent countries. Resources for pathology are scarce in many countries where Burkitt Lymphoma is endemic, leading to high rates of inaccurate diagnoses, thereby possibly contributing to the lower overall survival rates. A clinical care project at the Uganda Cancer Institute (UCI) in Kampala, Uganda has been following patients with Burkitt Lymphoma for more than 2 years, with preliminary data showing a high rate of diagnostic discordance. Method: All patients presenting for care at the UCI between July 2012 and July 2014 with suspected BL and two independent histopathologic evaluations of the same tumor biopsy were eligible for this study. Baseline demographic and clinical characteristics were described for the entire cohort and by discordance status. Kappa statistics were calculated to determine the rate of agreement between two pathology labs involved in the project. Poisson regression analysis was used to determine associations of baseline factors with discordance. To determine one year overall survival the Kaplan-Meier Method was used. Findings: 57 patients were eligible for the study. The percentage of discordance for BL vs. “other” was 32%. Older age and central nervous system involvement were associated with a higher frequency of discordant diagnosis. There was a trend towards elevated LDH being associated with discordance, though this was not statistically significant. These associations were attenuated when adjusting for age. Overall survival was 55% for the entire cohort, and 70% and 39% for patients without and with discordance respectively. The difference in survival between the groups did not meet statistical significance. Conclusions: Discordance was a frequent event in our study setting. Baseline factors associated with discordance may be used to guide decisions regarding more extensive diagnostic workup, but need to be confirmed in larger studies. Cheaper and sustainable pathology testing needs to be made available for countries with limited resources.