[1498] Utility of Karyotype and FISH in Treated Myeloma Patients with No Morphologic Evidence of Disease

Claudio Mosse, Adam Seegmiller, Annette Kim, Megan Kressin. Vanderbilt University Medical Center, Nashville, TN; Tennessee Valley Healthcare Systems VA, Nashville, TN

Background: Karyotype and FISH studies are routinely performed on bone marrow (BM) aspirate specimens from plasma cell myeloma patients during therapy. Although several studies have shown the prognostic utility of cytogenetic aberrations at diagnosis, fewer have shown utility of these data during follow-up. Moreover, the utility of FISH and karyotype to detect residual disease in morphologically negative (MN) follow-up BM is controversial, yet often performed. In this study we assess the utility of protein studies, cytogenetics and FISH to detect clonal plasma cells in MN BM.
Design: We retrospectively collected results of bone marrow morphology, cytogenetic tests, and protein studies (including electrophoresis (SPEP/UPEP), immunofixation (IFE), and free light chain (SFLC/UFLC) analyses) on all myeloma patients that had BM biopsies performed between August 2010 and February 2011. These results were correlated with those from previous and subsequent BM biopsies.
Results: A total of 229 BM biopsies were performed on myeloma patients at VUMC during the 6-month span analyzed. Of these, 115 (50%) were morphologically positive (MP) while 114 (50%) were negative (MN). Karyotype was abnormal in 4% of MN cases and in 17% of MP cases. FISH was abnormal in 4% of MN cases and in 46% of MP cases. In contrast, protein studies in MN cases were positive in 71%. SPEP/IFE was positive in 50%, UPEP/IFE in 30%, SFLC in 30% and UFLC in 37%. In the two MN cases with abnormal karyotype or FISH that were negative for all protein studies, the abnormality was not seen subsequently, likely a transient false positive result. Therefore, there were no MN cases that showed a disease associated karyotype or FISH abnormality that did not also show evidence of clonality by protein studies. However, 65% (74/114) MN cases had positive protein studies but were negative by karyotype or FISH.
Conclusions: In MN BM, karyotype and FISH studies provide no additional benefit to protein studies in the detection of residual myeloma. Amongst protein studies, SPEP with IFE is the most sensitive, although UPEP with IFE and S/UFLC provided additional sensitivity in detecting residual disease. Because Medicare reimbursements for a myeloma FISH panel and karyotype total approximately $1453, eliminating this unnecessary testing in MN patients in this study would have prevented over $330,000 in unnecessary charges.
Category: Hematopathology

Wednesday, March 21, 2012 1:00 PM

Poster Session VI # 225, Wednesday Afternoon

 

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