Neoplastic Plasma Cells Are Demonstrable at Bone Marrow Sites Distant to Solitary Plasmacytoma of Bone and Predict for Progression to Multiple Myeloma.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 3512-3512 ◽  
Author(s):  
Quentin A. Hill ◽  
Ruth M. de Tute ◽  
J. Anthony Child ◽  
Andy C. Rawstron ◽  
Roger G. Owen

Abstract Solitary plasmacytoma of bone (SPB) typically present as single destructive lesions within the spinal column or long bones. Local radiotherapy is the treatment of choice but approximately 50% of patients progress to myeloma. Many patients have a monoclonal protein detectable in their serum and/or urine at diagnosis and persistence of this for greater than 1 year after radiotherapy predicts for progression to myeloma. Identification of high risk patients at the time of diagnosis is clearly desirable as it would enable risk stratification and more careful monitoring of patients. Although prophylactic adjunctive chemotherapy has not definitively been shown to benefit unselected patients with SPB, future therapeutic advances might be targeted on patients with a high risk of progression. Interestingly it has recently been shown that patients positive for serum free light chains are at greater risk of progression to myeloma. We and others have previously demonstrated that neoplastic bone marrow plasma cells are distinguishable from their normal counterparts by virtue of their lack of CD19 expression and/or their aberrant expression of CD56. We have developed a multiparameter flow cytometry assay which predicts outcome following autologous transplantation in myeloma patients and risk of progression in patients with MGUS. In this study we have applied this assay to assess the staging bone marrow specimens from patients with biopsy proven SPB for the presence of occult disease at sites distant to the primary lesion. 52 patients were included in this analysis (31 male, 21 female; median age 65) and in each case the staging bone marrow aspirate and trephine biopsy (obtained from a site distant from the SPB, typically the right iliac crest) was not indicative of myeloma (<10% plasma cells). Plasma cells comprised a median of 0.6% (0.05–6.2%) of bone marrow leucocytes while distinct populations with a neoplastic immunophenotype (>30% CD19− and/or CD56+ as per convention) were demonstrable in 35/52 (67%). Neoplastic plasma cells when present comprised a median of 70% (35–100%) of bone marrow plasma cells. 21 patients (40%) developed myeloma with a median time to progression of 476 days (range 18–1632). Progression occurred in 18 of the 35 (51%) patients with neoplastic plasma cells in their staging marrows and in 3/17 (18%) patients with a normal phenotypic profile. The difference was significant using Chi-square analysis with Yates’ correction for continuity (p=0.04). The overall risk of progression was similar in patients with a “myeloma pattern” in which >90% of bone marrow plasma cells had a neoplastic phenotype (5/12, 42%) and those with an MGUS or mixed pattern in which distinct populations of both normal and neoplastic cells are demonstrable (13/23, 57%). We would conclude that neoplastic plasma cells are frequently found at bone marrow sites distant to SPB and that their presence predicts for progression to multiple myeloma. Trials of adjuvant systemic therapy are warranted in this group.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 2804-2804
Author(s):  
AndrÉs Jerez ◽  
Francisco Ortuño ◽  
María del Mar Osma ◽  
Ignacio Español ◽  
Ana Gonzalez ◽  
...  

Abstract Abstract 2804 Poster Board II-780 Background: Monoclonal gammopathy of undetermined significance (MGUS) progresses to plasma cell dyscrasia, mainly multiple myeloma (MM), at a rate of approximately 1% per year. Moreover, recent studies have shown that MM is nearly always preceded by MGUS, encouraging investigators to find better predictors for MM development in order to implement strategies to prevent or delay progression. In addition, a high prevalence of MGUS has been noted in a series of patients with immune disorders or chronic infections. Multiparameter flow cytometry allows the identification and quantification of both monoclonal and polyclonal plasma cells. This study analyses the relationship between monoclonal and polyclonal bone marrow plasma cells (BMPC), studied by means of flow cytometry, and its association with either immune or infectious disorders, or the development of MM in newly diagnosed MGUS patients. Methods: We conducted a retrospective cohort study to analyse the prognostic value of the aberrant (CD38++ CD138+ CD19– CD45weak) to normal (CD38++ CD138+ CD19+ CD45+) phenotype bone marrow plasma cells ratio (A/N ratio) and another 13 variables at baseline for the development of a plasma cell dyscrasia. We also performed a cross-sectional study to evaluate the association of those variables at baseline with the presence of a chronic immune response disorder. In each patient, the following variables were examined: age, sex, hemoglobin, serum creatinine, serum calcium, B2-Microglobulin, type and size of the serum monoclonal component (MC), isotype of the MC immunoglobulin, presence of urine MC, quantification of serum immunoglobulin levels, erythrocyte sedimentation rate, BMPC percentage and presence of atypical plasma cells on light microscopy, and aberrant and normal phenotype BMPC percentages. The effect of variables on progression was calculated using a Cox proportional hazards regression model. To identify variables at baseline associated with immune or chronic infectious disorders. a series of univariate and multivariate analyses was fitted using a binary logistic regression strategy. Results: Between March 1997 and April 2008, flow cytometry analysis on bone-marrow samples was performed on 322 patients with newly diagnosed MGUS. Median patient age was 71 years (interquartile range (IQR) 63-78 years) with a slightly male predominance (51%). Median follow-up was 46 months (IQR 23-58 months). During the period of observation, in 23 (7.1%) patients a transformation was registered into: MM (n=22), and primary amyloidosis (n=1). A total of 24 (7.4%) patients had a diagnosis of autoimmune disorder, and 18 (5.6%) patients of a chronic infection. Multivariate analysis for progression to MM revealed an increased A/N ratio as the main independent prognostic variable. In addition, our study found a significant association between a reduced A/N ratio and the diagnosis of a chronic immune response related condition. Using receiver-operating characteristic analysis we created an A/N ratio range from 4 to 0.20. Values of 4 or higher define a group of MGUS patients at high risk of progression (OR, 10.7; 95% confidence interval 4.2-39), whereas A/N ratio values of 0.20 or lower are associated with immune disorders or chronic infections (OR, 20.9; 95% confidence interval 8.5-51.1). A total of 282 patients had an A/N ratio below 4, and 42 had values equal to or above the cut-off. Patients with an A/N ratio ≥ 4 had a cumulative probability of transformation of 35% at 5 years, compared with 3% for those with an A/N ratio < 4. Conclusions: Extreme values of the A/N ratio at diagnosis seem to be related with two different conditions: high risk MGUS, likely to progress to MM, and immune condition related MGUS. Our findings further support the routine use of phenotypic characterization of bone marrow plasma cells in patients with MGUS at diagnosis. Disclosures: No relevant conflicts of interest to declare.


Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 3926-3926
Author(s):  
Efstathios Kastritis ◽  
Lia A Moulopoulos ◽  
Maria Gkotzamanidou ◽  
Dimitra Gika ◽  
Maria Roussou ◽  
...  

Abstract Abstract 3926 Asymptomatic/smoldering multiple myeloma (SMM) is a proliferative plasma cell disorder characterized by a substantial risk of progression to symptomatic myeloma. According to current recommendations, patients with SMM should be followed without treatment until they develop symptomatic disease. However, the risk of progression to symptomatic myeloma varies between different series and for individual patients; thus, significant effort is needed in order to identify factors that could discriminate those who are at high risk for progression. Such patients should be followed closer and should be considered candidates for clinical trials. In order to evaluate previously recognized risk factors and study patterns of progression we analyzed our series of patients with SMM, who have been diagnosed and followed in the Department of Clinical Therapeutics in Athens, Greece. SMM was defined as serum monoclonal (M) protein (IgG or IgA) level of ≥3 g/dL and/or bone marrow plasma cells ≥10%, absence of end-organ damage, such as lytic bone lesions, anemia, hypercalcemia, or renal failure, that can attributed to a plasma cell proliferative disorder (IMWG criteria, Br J Haematol 2003;121:749–57). Progression to symptomatic myeloma was defined as per the IMWG proposed criteria. We analyzed 95 patients with SMM, 53% of whom were females, 70% had IgG heavy chain, 22% had IgA, 5% had a biclonal SMM and 3% had light chain only SMM, while 65% had a kappa light chain and 35% a lambda light chain. Median infiltration by clonal plasma cells in BM trephine biopsy was 20% (range 10–90%), 10% of patients had ≥60% clonal plasma cells in BM biopsy. Fifty patients had MRI of the spine at the time of diagnosis of SMM and 19.5% had an abnormal pattern of BM infiltration (diffuse, focal or variegated pattern). In patients with available bone marrow immunohistochemistry data, 61% had clonal plasma positive for CD56, 17% for CD20 and 19% for cyclin D1. The median follow up of the cohort was 27 months (range 1–253 months) and 23 (24%) patients have progressed to symptomatic myeloma. The one-year, 2-year and 3-year cumulative probability of progression was 7%, 12% and 20% respectively. Nine patients (9.5%) progressed within the first two years from the diagnosis of SMM. All these patients had an M-protein of ≥1 g/dl (10 g/L), 67% had bone marrow plasma cells >60% and 80% had an abnormal MRI pattern of BM infiltration. The 3-year probability of progression to symptomatic myeloma was 4%, 18% and 87% for patients with <20%, 20–59% and ≥60% clonal plasma cells in bone marrow biopsy (P<0.001). The 2-year probability of progression to symptomatic myeloma was 0%, 13% and 60% for patients with <20%, 20–59% and ≥60% clonal plasma cells in BM biopsy (P<0.001). Patients with significantly abnormal free light chain ratio (either kappa/lambda ≥8 or kappa/lambda ≤0.125, according to Dispenzieri et al, Blood 2008;111:785–9) had a 3-year probability of progression to symptomatic MM of 41% vs. 15% (p=0.07). There was no significant difference in the risk of progression to symptomatic MM for patients with IgA vs. IgG myeloma. In multivariate analysis, abnormal FLC ratio less than 0.125 or more than 8 (HR: 6.4, 95% CI 1.3–34.5 p=0.032) and BM clonal plasma cells infiltration ≥60% (HR: 23, 95% CI 5–125, p<0.001) were independent risk factors for progression to symptomatic myeloma. Progression to symptomatic MM was manifested by the development of anemia in 52% of patients who progressed to symptomatic MM, development of lytic bone lesions or pathologic fracture in 48%, an increase of serum creatinine to ≥2 mg/dl in 13%, development of a soft tissue plasmacytoma in 4% and development of hypercalcemia in 4%. In conclusion, in our series of patients the 3-year probability of progression to symptomatic myeloma is about 20%, but there is a subgroup of patients with extensive bone marrow infiltration (≥60%) and highly abnormal FLC ratio, who have a substantial risk of progression to symptomatic disease within the first two years from the diagnosis of SMM. These high risk patients may also have other features such as abnormal MRI of the spine. Patients at high risk for progression should be considered for clinical trials evaluating the role of treatment before the development of symptomatic disease, which in most cases is manifested with anemia and/or lytic bone disease or pathologic fractures. Disclosures: No relevant conflicts of interest to declare.


Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 3369-3369 ◽  
Author(s):  
Veronica Gonzalez de la Calle ◽  
Ramon Garcia-Sanz ◽  
Eduardo Sobejano ◽  
Enrique M. Ocio ◽  
Noemi Puig ◽  
...  

Abstract BACKGROUND Smoldering multiple myeloma (SMM) is a plasma cell proliferative disorder with no related organ or tissue impairment. It is associated with a risk of progression to symptomatic multiple myeloma (MM) of approximately 10% per year. Several prognostic factors for the progression to active disease have been identified, such as those defined by the Mayo Clinic including the proportion of bone marrow plasma cells, the serum monoclonal protein level at diagnosis and the serum immunoglobulin free light chain ratio (FLC); or those defined by the Spanish Group including the proportion of bone marrow aberrant plasma cells assessed by flow cytometry plus immunoparesis. The presence of Bence Jones (BJ) proteinuria is a myeloma feature associated with renal function and tumor burden as well. There is lack of evidence about the role of BJ proteinuria in SMM as predictor marker of progression to symptomatic disease. AIMS The goal of the present study was to investigate the role of the presence of Bence Jones proteinuria at diagnosis in SMM as predictor of progression to symptomatic disease. METHODS We reviewed 147 medical records of SMM patients from area of Castilla y León (Spain), diagnosed between 1983 and 2013, according to the criteria of the International Myeloma Working Group. The primary endpoint was time to progression to active multiple myeloma (hypercalcemia, renal insufficiency, anemia or bone lesions). RESULTS 147 patients with SMM were included in the analysis. The median age at diagnosis was 69 years-old (range: 34-90).The serum M-protein at diagnosis ranged from 1 to 26 g/l (median,25). 70% of SMM were Ig G subtype. The proportion of bone marrow plasma cells ranged from 1% to 55% (median, 14). In 64 % of SMM, the percentage of aberrant plasma cells assessed by flow cytometry was superior to 95% and 51% had immunoparesis. Bence Jones proteinuria was detected at diagnosis in 40 patients (27%) and the average amount of urinary monoclonal light chain was 236 mg per 24h. Of those patients, 58% had a monoclonal kappa light chain. The FLC ratio was assessed in 18 patients and it was abnormal (<0.26 or >1.65) in 83% of them. The median level of involved Immunoglobulin was 88.5 mg/l (range, 13-1200) and the median ratio of involved to uninvolved was 10.8 (range, 2.2-3360). In 4 patients, FLC ratio was greater than 100. At a median follow-up of 54 months, progression to active disease occurred in 49%. Anemia was the most common CRAB feature at the time of progression. Median time to progression (TTP) to symptomatic disease in the whole series was 63 months. SMM with BJ proteinuria had a significantly shorter median TTP to active disease as compared with patients without BJ proteinuria (21.7 months vs 82.9 months ;HR: 2.44, IC 95%: 1.48-4.02; p<0.001). The progression risk at 2 years in the BJ group of SMM was 53%. Multivariate analysis selected BJ proteinuria at diagnosis as an independent variable for progression to symptomatic MM (HR: 2.47, IC 95%: 1.32-4.63; P=0.005). Using this independent variable, we identified 4 risk categories according to amount of urinary monoclonal light chain: 0 mg per 24h; 1-250 mg/24h; 251-500 mg/24h ; or more than 500 mg/24h, with a median TTP of 83, 37, 16 and 7 months, respectively; p <0.001. CONCLUSIONS The presence of Bence Jones proteinuria at diagnosis in SMM patients is associated with significantly higher risk of progression to active MM (53% risk of progression at 2 years). Moreover, the presence of more than 500 mg of BJ proteinuria can be considered as a marker for the identification of ultra high risk SMM. Disclosures No relevant conflicts of interest to declare.


Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 1487-1487 ◽  
Author(s):  
Angela Dispenzieri ◽  
Robert A. Kyle ◽  
Jerry A. Katzmann ◽  
Dirk Larson ◽  
Joanne Benson ◽  
...  

Abstract Background: Smoldering multiple myeloma (SMM) is an asymptomatic plasma cell proliferative disorder with a high risk of progression to symptomatic multiple myeloma. Identification of risk factors that predict progression of SMM to symptomatic MM could identify higher risk patients who might benefit from chemoprevention or more intensive surveillance. We hypothesized that increased monoclonal free kappa or lambda immunoglobulin light chains in smoldering myeloma (SMM), as detected by the serum free light chain (FLC) assay, indicates an increased the risk of progression to active myeloma. Methods: Of 276 pathologically confirmed SMM patients seen at the Mayo Clinic from 1970 to 1995, baseline serum samples obtained within 30 days of diagnosis were available in 273. Results: At a median follow-up of surviving patients of 12.4 years, transformation to active disease has occurred in 161 (59%) patients. An abnormal FLC ratio was present at baseline in 90% of patients. The best break-point for predicting risk of progression was a FLC ratio less than or equal to 0.125 or greater than or equal to 8 (hazard ratio, 2.3; 95% CI, 1.6–3.2) [Figure 1]. The extent of abnormality of FLC ratio was independent of SMM risk categories defined by number of plasma cells in the bone marrow and size of serum M-proteins (bone marrow plasma cells ≥ 10% and serum M protein ≥ 3 g/dL; bone marrow plasma cells ≥ 10% but serum M protein &lt; 3 g/dL; and serum M protein ≥ 3 g/dL but bone marrow plasma cells &lt; 10%). Incorporating the FLC ratio into the risk model, the division of patients into high-, intermediate-, and low-risk groups is 28, 42, and 30% with 5 year progression rates of 76, 51, and 25%, respectively [Figure 2]. Conclusions: The serum immunoglobulin FLC ratio is an important additional determinant of clinical outcome in patients with SMM. Figure Figure Figure Figure


Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 1649-1649
Author(s):  
Omar Nadeem ◽  
Robert A. Redd ◽  
Michael Z. Koontz ◽  
Jeffrey V. Matous ◽  
Andrew J. Yee ◽  
...  

Abstract Introduction : Daratumumab (Dara) is an anti-CD38 monoclonal antibody that is approved for use in patients with newly diagnosed and relapsed multiple myeloma (MM). We hypothesized that early therapeutic intervention with Dara in patients with high-risk MGUS (HR-MGUS) or low-risk SMM (LR-SMM) would lead to eradication of the tumor clone by achieving deep responses, resulting in prevention of progression to MM. We present results of our phase II, single arm study of Dara in HR-MGUS and LR-SMM. Methods : Patients enrolled on this study met eligibility for either HR-MGUS or LR-SMM. HR-MGUS is defined as &lt;10% bone marrow plasma cells and &lt;3g/dL M protein and at least 2 of the following 3 high-risk criteria: Abnormal serum free light chain ratio (SFLC) of &lt;0.26 or &gt;1.65, M protein ≥ 1.5g/dL or non-IgG M protein. LR-SMM is defined by one of the following 3 criteria: M protein ≥3g/dL, ≥10% bone marrow plasma cells, SFLC ratio &lt;0.125 or &gt;8. Dara (16mg/kg) was administered intravenously on a weekly schedule for cycles 1-2, every other week cycles 3-6, and monthly during cycles 7-20. The primary objective of this study was to determine the proportion of patients who achieve very good partial response (VGPR) or greater after 20 cycles of Dara. Secondary objectives included duration of response, safety, and rates of minimal residual disease (MRD)-negativity in VGPR or greater patients. Correlative studies included assessing changes in immune microenvironment, evaluating clonal heterogeneity using deep sequencing, and determining association of genomic aberrations correlating with either response to therapy or progression of disease. Results : At the time of data cutoff, a total of 42 patients were enrolled on this study from 2018 to 2020 with participation of 5 sites. The median age for all patients at enrolment was 60 years (range 38 to 76), with 22 males (52.4%) and 20 females (47.6%). Majority of patients enrolled were classified as LR-SMM (n = 37, 88.1%) and the remaining 5 patients had HR-MGUS (11.9%). 41 patients have started treatment and are included in toxicity assessment, and 40 patients have at least completed 16 cycles (range 6-20). Grade 3 toxicities were rare and only experienced in 5/41 patients including diarrhea (n =1/41; 2%), flu like symptoms (n = 1/41; 2%), headache (n=1/41; 2%), and hypertension (n=2/41; 5%). Most common toxicities of any grade included fatigue (n = 24/41, 51%), cough (n = 19/41, 46%), nasal congestion (n = 18/41, 44%), headache (n = 14/41, 34%), hypertension (n = 11/41, 27%), nausea (n = 13/41, 32%), and leukopenia (n = 13/41, 32%). No patients have discontinued therapy due to toxicity. Minimal response or better was observed in 82.9% of patients (34/41) and PR or better was observed in 51.2% of patients (21/41). This included overall CR (n = 4, 9.8%), VGPR (n = 1, 2.4%), PR (n = 16, 39.0%), MR (n = 13, 31.7%), and SD (n = 7, 17.1%). In the 40 patients who completed at least 16 cycles, response rates were as follows: MR or better 85% (34/40), PR or better 52.5% (21/40) and VGPR or better 12.5% (5/40). Median time to VGPR was 7 months. Median overall survival and progression-free survival have not been reached and no patients have progressed to overt multiple myeloma while on study. Conclusion : Dara is very well tolerated among patients with HR-MGUS and LR-SMM with minimal toxicities. Responses are seen in majority of patients. Early therapeutic intervention in this precursor patient population appears promising but longer follow up is required to define the role of single agent Dara in preventing progression to MM, therefore avoiding more toxic interventions in this low-risk patient population. Disclosures Nadeem: Karyopharm: Membership on an entity's Board of Directors or advisory committees; GSK: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; Adaptive Biotechnologies: Membership on an entity's Board of Directors or advisory committees; BMS: Membership on an entity's Board of Directors or advisory committees. Yee: GSK: Consultancy; Oncopeptides: Consultancy; Janssen: Consultancy; Amgen: Consultancy; Sanofi: Consultancy; Bristol Myers Squibb: Consultancy; Adaptive: Consultancy; Takeda: Consultancy; Karyopharm: Consultancy. Zonder: Caelum Biosciences: Consultancy; Amgen: Consultancy; BMS: Consultancy, Research Funding; Intellia: Consultancy; Alnylam: Consultancy; Janssen: Consultancy; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees; Regeneron: Consultancy. Rosenblatt: Attivare Therapeutics: Consultancy; Imaging Endpoints: Consultancy; Parexel: Consultancy; Karyopharm: Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Research Funding; Wolters Kluwer Health: Consultancy, Patents & Royalties. Mo: AbbVIE: Consultancy; BMS: Membership on an entity's Board of Directors or advisory committees; Eli Lilly: Consultancy; Epizyme: Consultancy; GSK: Consultancy, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria; Karyopharm: Honoraria, Membership on an entity's Board of Directors or advisory committees; Sanofi: Honoraria, Membership on an entity's Board of Directors or advisory committees. Sperling: Adaptive: Consultancy. Richardson: Karyopharm: Consultancy, Research Funding; AstraZeneca: Consultancy; AbbVie: Consultancy; Takeda: Consultancy, Research Funding; Celgene/BMS: Consultancy, Research Funding; Janssen: Consultancy; GlaxoSmithKline: Consultancy; Protocol Intelligence: Consultancy; Secura Bio: Consultancy; Regeneron: Consultancy; Sanofi: Consultancy; Oncopeptides: Consultancy, Research Funding; Jazz Pharmaceuticals: Consultancy, Research Funding. Ghobrial: AbbVie, Adaptive, Aptitude Health, BMS, Cellectar, Curio Science, Genetch, Janssen, Janssen Central American and Caribbean, Karyopharm, Medscape, Oncopeptides, Sanofi, Takeda, The Binding Site, GNS, GSK: Consultancy.


Blood ◽  
1984 ◽  
Vol 64 (2) ◽  
pp. 352-356
Author(s):  
GJ Ruiz-Arguelles ◽  
JA Katzmann ◽  
PR Greipp ◽  
NJ Gonchoroff ◽  
JP Garton ◽  
...  

The bone marrow and peripheral blood of 14 patients with multiple myeloma were studied with murine monoclonal antibodies that identify antigens on plasma cells (R1–3 and OKT10). Peripheral blood lymphocytes expressing plasma cell antigens were found in six cases. Five of these cases expressed the same antigens that were present on the plasma cells in the bone marrow. Patients that showed such peripheral blood involvement were found to have a larger tumor burden and higher bone marrow plasma cell proliferative activity. In some patients, antigens normally found at earlier stages of B cell differentiation (B1, B2, and J5) were expressed by peripheral blood lymphocytes and/or bone marrow plasma cells.


2014 ◽  
Author(s):  
Maria Gkotzamanidou ◽  
Masood Shammas ◽  
Evangelos Terpos ◽  
Sathees C. Raghavan ◽  
Kenneth C. Anderson ◽  
...  

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Byung-Hyun Lee ◽  
Yong Park ◽  
Ji Hye Kim ◽  
Ka-Won Kang ◽  
Seung Jin Lee ◽  
...  

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 5080-5080 ◽  
Author(s):  
David Dingli ◽  
Robert A. Kyle ◽  
Vincent S. Rajkumar ◽  
Grzegorz S. Nowakowski ◽  
Dirk R. Larson ◽  
...  

Abstract Background: Solitary plasmacytoma of bone (SBP) is a localized collection of monoclonal plasma cells that is potentially curable with local radiation therapy but associated with a high risk of progression to multiple myeloma. We hypothesized that an abnormal immunoglobulin free light (FLC) ratio at diagnosis may be a prognostic indicator of transformation risk. Methods: We identified a cohort of 133 patients with SBP for whom stored serum taken at the time of diagnosis was available. The diagnosis was ascertained and serum FLC determined in 126 patients. Results: From this cohort, 48 patients have progressed to myeloma and the median time to progression among those who progressed was 1.9 years. On univariate analysis, age (p&lt;0.001), gender (p=0.035), abnormal FLC ratio at diagnosis (p=0.009) and persistence of serum or urine M-protein after therapy (p=0.0070 were all associated with a shorter overall survival (OS) and time to progression to multiple myeloma. Progression by Normal FLC(0.26–1.65) Progression by Normal FLC(0.26–1.65) On multivariate analysis, an abnormal FLC ratio retained its independence in a model that includes age at diagnosis but lost its significance when combined with persistence of the serum or urine M-protein. However, serum or urine M-proteins are not detectable in a significant number of patients with SBP and therefore not informative. Conclusion: The FLC ratio at the time of diagnosis of SBP is a powerful predictor of risk and a useful aid to management of patients with this condition.


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