title: Critical analysis of the stringent complete response in multiple myeloma: contribution of sFLC and bone marrow clonality.
abstract: Stringent complete response (sCR) criteria are used in multiple myeloma as a deeper response category compared with CR, but prospective validation is lacking, it is not always clear how evaluation of clonality is performed, and is it not known what the relative clinical influence is of the serum free light chain ratio (sFLCr) and bone marrow (BM) clonality to define more sCR. To clarify this controversy, we focused on 94 patients that reached CR, of which 69 (73%) also fulfilled the sCR criteria. Patients with sCR displayed slightly longer time to progression (median, 62 vs 53 months, respectively; P = .31). On analyzing this contribution to the prognosis of sFLCr or clonality, it was found that the sFLCr does not identify patients in CR at distinct risk; by contrast, low-sensitive multiparametric flow cytometry (MFC) immunophenotyping (2 colors), which is equivalent to immunohistochemistry, identifies a small number of patients (5 cases) with high residual tumor burden and dismal outcome; nevertheless, using traditional 4-color MFC, persistent clonal BM disease was detectable in 36% of patients, who, compared with minimal residual disease-negative cases, had a significantly inferior outcome. These results show that the current definition of sCR should be revised.
authors.affiliation: Hematology Department, Hospital Universitario 12 de Octubre, Madrid, Spain;
authors.forename: Joaquín
authors.initials: J
authors.lastname: Martínez-López
authors.affiliation: Hematology Department, Clinica Universidad de Navarra, Centro de Investigación Medica Aplicada, Instituto de Investigación Sanitaria de Navarra, Pamplona, Spain;
authors.forename: Bruno
authors.initials: B
authors.lastname: Paiva
authors.affiliation: Hematology Department, Hospital Universitario 12 de Octubre, Madrid, Spain;
authors.forename: Lucía
authors.initials: L
authors.lastname: López-Anglada
authors.affiliation: Hematology Department, Hospital Universitario de Salamanca-Instituto de Investigación Biomédica de Salamanca, Instituto de Biología Molecular y Celular del Cáncer de Salamanca-Centro de Investigación del Cáncer, Salamanca, Spain;
authors.forename: María-Victoria
authors.initials: MV
authors.lastname: Mateos
authors.affiliation: Hematology Department, Hospital Universitario 12 de Octubre, Madrid, Spain;
authors.forename: Teresa
authors.initials: T
authors.lastname: Cedena
authors.affiliation: Hematology Department, Hospital Universitario de Salamanca-Instituto de Investigación Biomédica de Salamanca, Instituto de Biología Molecular y Celular del Cáncer de Salamanca-Centro de Investigación del Cáncer, Salamanca, Spain;
authors.forename: María-Belén
authors.initials: MB
authors.lastname: Vidríales
authors.affiliation: Hematology Department, Hospital Universitario 12 de Octubre, Madrid, Spain;
authors.forename: María Auxiliadora
authors.initials: MA
authors.lastname: Sáez-Gómez
authors.affiliation: Hematology Department, Hospital Universitario de Salamanca-Instituto de Investigación Biomédica de Salamanca, Instituto de Biología Molecular y Celular del Cáncer de Salamanca-Centro de Investigación del Cáncer, Salamanca, Spain;
authors.forename: Teresa
authors.initials: T
authors.lastname: Contreras
authors.affiliation: Hematology Department, Hospital Germans i Trials, Barcelona, Spain;
authors.forename: Albert
authors.initials: A
authors.lastname: Oriol
authors.affiliation: Hematology Department, Hospital Universitario 12 de Octubre, Madrid, Spain;
authors.forename: Inmaculada
authors.initials: I
authors.lastname: Rapado
authors.affiliation: Hematology Department, Hospital Clínico de Valencia, Valencia, Spain;
authors.forename: Ana-Isabel
authors.initials: AI
authors.lastname: Teruel
authors.affiliation: Hematology Department, Hospital La Fe, Valencia, Spain;
authors.forename: Lourdes
authors.initials: L
authors.lastname: Cordón
authors.affiliation: Hematology Department, Hospital Ramon y Cajal, Madrid, Spain;
authors.forename: María Jesús
authors.initials: MJ
authors.lastname: Blanchard
authors.affiliation: Hematology Department, Hospital de Donostia, San Sebastián, Spain;
authors.forename: Enrique
authors.initials: E
authors.lastname: Bengoechea
authors.affiliation: Hematology Department, Hospital Clínico Universitario, Zaragoza, Spain;
authors.forename: Luis
authors.initials: L
authors.lastname: Palomera
authors.affiliation: Hematology Department, Hospital Morales Messeguer, Murcia, Spain;
authors.forename: Felipe
authors.initials: F
authors.lastname: de Arriba
authors.affiliation: Hematology Department, Hospital Universitario 12 de Octubre, Madrid, Spain;
authors.forename: Cecilia
authors.initials: C
authors.lastname: Cueto-Felgueroso
authors.affiliation: Hematology Department, Servicio General de Citometría and Departamento de Medicina, Universidad de Salamanca, Salamanca, Spain; and.
authors.forename: Alberto
authors.initials: A
authors.lastname: Orfao
authors.affiliation: Hematology Department, Hospital Clinic, Institut d'Investigacions Biomédiques August Pi I Sunyer, Barcelona, Spain.
authors.forename: Joan
authors.initials: J
authors.lastname: Bladé
authors.affiliation: Hematology Department, Clinica Universidad de Navarra, Centro de Investigación Medica Aplicada, Instituto de Investigación Sanitaria de Navarra, Pamplona, Spain;
authors.forename: Jesús F
authors.initials: JF
authors.lastname: San Miguel
authors.affiliation: Hematology Department, Hospital Universitario 12 de Octubre, Madrid, Spain;
authors.forename: Juan José
authors.initials: JJ
authors.lastname: Lahuerta
mesh_terms: D001853:Bone Marrow / Q000473:pathology*; D016026:Bone Marrow Transplantation; D018572:Disease-Free Survival; D006801:Humans; D007147:Immunoglobulin Light Chains / Q000097:blood*; D053208:Kaplan-Meier Estimate; D009101:Multiple Myeloma / Q000276:immunology* / Q000473:pathology* / Q000628:therapy; D012074:Remission Induction; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D007147:Immunoglobulin Light Chains