title: Secondary monoclonal gammopathy of undetermined significance after allogeneic stem cell transplantation in multiple myeloma.
abstract: In the course of multiple myeloma, patients may develop a M-protein band different from the original: secondary monoclonal gammopathy of undetermined significance. In this retrospective single center analysis, we describe the occurrence and clinical relevance of secondary monoclonal gammopathy of undetermined significance after allogeneic stem cell transplantation (post-transplant monoclonal gammopathy of undetermined significance). A total of 138 patients who had undergone 139 allogeneic stem cell transplantations (39.6% in the upfront setting and 60.4% for relapsed multiple myeloma) were included in the study. Sixty-seven (48.2%) patients developed secondary monoclonal gammopathy of undetermined significance, after a median latency of 6.9 months. Secondary monoclonal gammopathy of undetermined significance occurred more often in patients who achieved at least very good partial response after allogeneic stem cell transplantation, compared to partial response or less (54.8% vs. 26.5%; P=0.005). The incidence was also higher in the upfront setting as compared to relapsed disease, or with a sibling donor compared to matched unrelated donor, but less often after T-cell depletion. Importantly, development of post-transplant monoclonal gammopathy of undetermined significance as a time-dependent variable independently predicted for superior progression-free and overall survival (median progression-free survival 37.5 vs. 6.3 months, P<0.001; median overall survival 115.3 vs. 31.0 months, P=0.004). Clinicians should be aware of the benign nature of this phenomenon, and secondary monoclonal gammopathy of undetermined significance should not be confused with relapse or progression of disease. (Trial registered with trialregister.nl; HOVON 108: NTR 2958.).
authors.affiliation: Department of Hematology, University Medical Center Utrecht;
authors.forename: Marian F
authors.initials: MF
authors.lastname: Schmitz
authors.affiliation: Laboratory for Translational Immunology, University Medical Center Utrecht;
authors.forename: Henny G
authors.initials: HG
authors.lastname: Otten
authors.affiliation: Department of Hematology, University Medical Center Utrecht; Department of Hematology, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Laurens E
authors.initials: LE
authors.lastname: Franssen
authors.affiliation: Department of Hematology, University Medical Center Utrecht;
authors.forename: Suzanne
authors.initials: S
authors.lastname: van Dorp
authors.affiliation: Laboratory for Translational Immunology, University Medical Center Utrecht;
authors.forename: Theo
authors.initials: T
authors.lastname: Strooisma
authors.affiliation: Department of Hematology, University Medical Center Utrecht; Department of Hematology, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Henk M
authors.initials: HM
authors.lastname: Lokhorst
authors.affiliation: Department of Hematology, University Medical Center Utrecht; Department of Hematology, VU University Medical Center, Amsterdam, The Netherlands n.vandedonk@vumc.nl.
authors.forename: Niels W C J
authors.initials: NW
authors.lastname: van de Donk
mesh_terms: D000328:Adult; D000368:Aged; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D018380:Hematopoietic Stem Cell Transplantation / Q000009:adverse effects*; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D008998:Monoclonal Gammopathy of Undetermined Significance / Q000453:epidemiology / Q000209:etiology* / Q000401:mortality / Q000473:pathology; D009101:Multiple Myeloma / Q000150:complications* / Q000401:mortality / Q000473:pathology / Q000628:therapy; D009364:Neoplasm Recurrence, Local / Q000401:mortality / Q000473:pathology / Q000628:therapy*; D009367:Neoplasm Staging; D009426:Netherlands / Q000453:epidemiology; D011379:Prognosis; D012189:Retrospective Studies; D015996:Survival Rate; D014184:Transplantation, Homologous