DLBCL and the 2008 WHO: What Does Subclassification Cost?
AS Chang, C Giudice, D Chang, TS Barry, S Chen, MK Hibbard, R Chen, DP O'Malley. Clarient Inc., Aliso Viejo, CA
Background: The 2008 WHO classification includes 22 separate variants and subtypes of diffuse large B cell lymphoma (DLBCL). Only some have significant impact both on prognosis and therapy. Accurate diagnosis is dependent on an increasingly complex and varied panel of tests. We evaluated a series of DLBCL, aggressive B cell lymphomas (ABL) and Burkitt lymphomas (BL) with a panel of ancillary tests for subclassification. Testing was based on NCCN guidelines and WHO classification. We approached subclassification based on relevance to therapy and prognosis, and cost of additional classification.
Design: We evaluated 100 large cell lymphomas, including cases of DLBCL, Burkitt lymphoma, EBV+ DLBCL, plasmablastic lymphoma, T-cell rich B-cell lymphoma (TCRBCL), and ABL. Cases were evaluated with a panel of antibodies (CD3, CD20, CD5, CD10, BCL2, BCL6, MUM1, Ki67), in situ EBV (EBER) and FISH (C-MYC break-apart, IGH/C-MYC, IGH/BCL2 and BCL6 break-apart). Approximate costs of the studies were based on 2009 Medicare fee schedules for the following tests: IHC per stain – 88342 - $115; paraffin FISH per probe – 88274+88365+88291 - $540; in situ stain – 88365 - $185; surgical pathology – 88305 - $125.
Results: 49% were nodal, with an average age of 67 years and M:F ratio of 1:1. 72 cases (72%) were DLBCL with 7 being EBV+. Of the remaining, there were 13 ABL, 3 TCRBCL, 3 BL, and 2 plasmablastic lymphomas. Of 72 DLBCL cases, 51% were GC, 9% were positive for CMYC, 18% were positive for IGH/BCL2, and 21% were positive for BCL6 rearrangement. Algorithms for diagnosis were evaluated based on: 1) therapeutic differences, 2) prognostic differences and 3) subclassification per 2008 WHO. Costs were calculated for each classification approximating relevant testing in each group.
Conclusions: We evaluated 100 cases of DLBCL and related lymphomas in order to speculate on: the incidence of abnormal findings with ancillary tests, 2) the cost and relevance of testing for these lymphomas. Besides basic diagnostic testing, we found considerable variation in cost between testing “required” by the NCCN ($1045), “useful” per NCCN ($2540), relevant to prognosis ($1770) and associated with therapeutic decisions ($895 conservative, $1335 extended). Our results suggest that both C-MYC FISH and EBV (EBER) should be performed in DLBCL. Further, FISH provided useful diagnostic and prognostic information in 61% of cases and should be considered as a useful adjunct. Other ancillary testing should be considered in the context of diagnosis, prognosis and therapeutic decisions.
Monday, March 22, 2010 2:30 PM
Platform Session: Section B, Monday Afternoon