Impact of initial FDG-PET/CT and serum-free light chain on transformation of conventionally defined solitary plasmacytoma to multiple myeloma.
OBJECTIVE
Solitary plasmacytoma (SP) is a localized proliferation of monoclonal plasma cells in either bone or soft tissue, without evidence of multiple myeloma (MM), and whose prognosis is marked by a high risk of transformation to MM.


METHODS
We studied the impact of FDG-PET/CT (2[18F]fluoro-2-deoxy-D-glucose positron emission tomography-computed tomography) on the risk of transformation of SP to overt MM among other markers in a series of 43 patients diagnosed with SP.


RESULTS
Median age was 57.5 years; 48% of patients had an abnormal involved serum-free light chain (sFLC) value, and 64% had an abnormal sFLC ratio at diagnosis. Thirty-three percent had two or more hypermetabolic lesions on initial PET/CT, and 20% had two or more focal lesions on initial MRI. With a median follow-up of 50 months, 14 patients transformed to MM with a median time (TTMM) of 71 months. The risk factors that significantly shortened TTMM at diagnosis were two or more hypermetabolic lesions on PET/CT, abnormal sFLC ratio and involved sFLC, and to a lesser extent at completion of treatment, absence of normalized involved sFLC and PET/CT or MRI. In a multivariate analysis, abnormal initial involved sFLC [OR = 10; 95% confidence interval (CI), 1-87; P = 0.008] and PET/CT (OR = 5; 95% CI, 0-9; P = 0.032) independently shortened TTMM.


CONCLUSIONS
An abnormal involved sFLC value and the presence of at least two hypermetabolic lesions on PET/CT at diagnosis of SP were the two predictors of early evolution to myeloma in our series. This data analysis will need confirmation in a larger study, and the study of these two risk factors may lead to a different management of patients with SP in the future. .
Authors' Affiliations: Service des maladies du sang; Médecine nucléaire, Hôpital Huriez, CHRU, Lille; Hématologie, Hôpital Côte de Nacre, CHU, Caen; Hématologie, Hôpital Sud, CHU, Rennes, France.
Guillemette
G
Fouquet
Authors' Affiliations: Service des maladies du sang; Médecine nucléaire, Hôpital Huriez, CHRU, Lille; Hématologie, Hôpital Côte de Nacre, CHU, Caen; Hématologie, Hôpital Sud, CHU, Rennes, France.
Stéphanie
S
Guidez
Authors' Affiliations: Service des maladies du sang; Médecine nucléaire, Hôpital Huriez, CHRU, Lille; Hématologie, Hôpital Côte de Nacre, CHU, Caen; Hématologie, Hôpital Sud, CHU, Rennes, France.
Charles
C
Herbaux
Authors' Affiliations: Service des maladies du sang; Médecine nucléaire, Hôpital Huriez, CHRU, Lille; Hématologie, Hôpital Côte de Nacre, CHU, Caen; Hématologie, Hôpital Sud, CHU, Rennes, France.
Zoé
Z
Van de Wyngaert
Authors' Affiliations: Service des maladies du sang; Médecine nucléaire, Hôpital Huriez, CHRU, Lille; Hématologie, Hôpital Côte de Nacre, CHU, Caen; Hématologie, Hôpital Sud, CHU, Rennes, France.
Sarah
S
Bonnet
Authors' Affiliations: Service des maladies du sang; Médecine nucléaire, Hôpital Huriez, CHRU, Lille; Hématologie, Hôpital Côte de Nacre, CHU, Caen; Hématologie, Hôpital Sud, CHU, Rennes, France.
David
D
Beauvais
Authors' Affiliations: Service des maladies du sang; Médecine nucléaire, Hôpital Huriez, CHRU, Lille; Hématologie, Hôpital Côte de Nacre, CHU, Caen; Hématologie, Hôpital Sud, CHU, Rennes, France.
Hélène
H
Demarquette
Authors' Affiliations: Service des maladies du sang; Médecine nucléaire, Hôpital Huriez, CHRU, Lille; Hématologie, Hôpital Côte de Nacre, CHU, Caen; Hématologie, Hôpital Sud, CHU, Rennes, France.
Salim
S
Adib
Authors' Affiliations: Service des maladies du sang; Médecine nucléaire, Hôpital Huriez, CHRU, Lille; Hématologie, Hôpital Côte de Nacre, CHU, Caen; Hématologie, Hôpital Sud, CHU, Rennes, France.
Bénédicte
B
Hivert
Authors' Affiliations: Service des maladies du sang; Médecine nucléaire, Hôpital Huriez, CHRU, Lille; Hématologie, Hôpital Côte de Nacre, CHU, Caen; Hématologie, Hôpital Sud, CHU, Rennes, France.
Mathieu
M
Wemeau
Authors' Affiliations: Service des maladies du sang; Médecine nucléaire, Hôpital Huriez, CHRU, Lille; Hématologie, Hôpital Côte de Nacre, CHU, Caen; Hématologie, Hôpital Sud, CHU, Rennes, France.
Céline
C
Berthon
Authors' Affiliations: Service des maladies du sang; Médecine nucléaire, Hôpital Huriez, CHRU, Lille; Hématologie, Hôpital Côte de Nacre, CHU, Caen; Hématologie, Hôpital Sud, CHU, Rennes, France.
Louis
L
Terriou
Authors' Affiliations: Service des maladies du sang; Médecine nucléaire, Hôpital Huriez, CHRU, Lille; Hématologie, Hôpital Côte de Nacre, CHU, Caen; Hématologie, Hôpital Sud, CHU, Rennes, France.
Valérie
V
Coiteux
Authors' Affiliations: Service des maladies du sang; Médecine nucléaire, Hôpital Huriez, CHRU, Lille; Hématologie, Hôpital Côte de Nacre, CHU, Caen; Hématologie, Hôpital Sud, CHU, Rennes, France.
Margaret
M
Macro
Authors' Affiliations: Service des maladies du sang; Médecine nucléaire, Hôpital Huriez, CHRU, Lille; Hématologie, Hôpital Côte de Nacre, CHU, Caen; Hématologie, Hôpital Sud, CHU, Rennes, France.
Olivier
O
Decaux
Authors' Affiliations: Service des maladies du sang; Médecine nucléaire, Hôpital Huriez, CHRU, Lille; Hématologie, Hôpital Côte de Nacre, CHU, Caen; Hématologie, Hôpital Sud, CHU, Rennes, France.
Thierry
T
Facon
Authors' Affiliations: Service des maladies du sang; Médecine nucléaire, Hôpital Huriez, CHRU, Lille; Hématologie, Hôpital Côte de Nacre, CHU, Caen; Hématologie, Hôpital Sud, CHU, Rennes, France.
Damien
D
Huglo
Authors' Affiliations: Service des maladies du sang; Médecine nucléaire, Hôpital Huriez, CHRU, Lille; Hématologie, Hôpital Côte de Nacre, CHU, Caen; Hématologie, Hôpital Sud, CHU, Rennes, France xavier.leleu@chru-lille.fr.
Xavier
X
Leleu
D000368:Aged; D014408:Biomarkers, Tumor / Q000032:analysis; D001859:Bone Neoplasms / Q000378:metabolism / Q000401:mortality / Q000473:pathology*; D002471:Cell Transformation, Neoplastic / Q000378:metabolism / Q000473:pathology*; D005260:Female; D019788:Fluorodeoxyglucose F18; D005500:Follow-Up Studies; D006801:Humans; D007147:Immunoglobulin Light Chains / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009101:Multiple Myeloma / Q000378:metabolism / Q000401:mortality / Q000473:pathology*; D009367:Neoplasm Staging; D010954:Plasmacytoma / Q000378:metabolism / Q000401:mortality / Q000473:pathology*; D049268:Positron-Emission Tomography / Q000379:methods*; D011379:Prognosis; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D015996:Survival Rate; D014057:Tomography, X-Ray Computed / Q000379:methods*
D014408:Biomarkers, Tumor; D007147:Immunoglobulin Light Chains; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18