Prognostic Value Of ¹⁸F-FDG PET/CT Imaging In Newly Diagnosed Multiple Myeloma And Construction Of A Novel Prognostic Model

Objective:Multiple myeloma（MM）is characterized by abnormal bone marrow plasma cell proliferation,which can secrete a large number of monoclonal immunoglobulins or their fragments,and bone disease is one of the main symptoms of MM,affecting the quality of life of patients.The detection of bone disease can help the diagnosis and risk stratification of MM,early identification of patients,so as to carry out effective intervention treatment.PET/CT is a novel imaging technique that is increasingly used in MM.In this paper,we mainly investigated the correlation between ¹⁸F-FDG PET/CT and the general data and laboratory data of newly diagnosed multiple myeloma（NDMM）patients and assessed its value in prognosis,and based on ¹⁸F-FDG PET/CT,a novel prognostic risk model was established,which can be used to predict progression-free survival（PFS）and overall survival（OS）in newly diagnosed MM patients.Method:The clinical data of 98 MM patients who underwent ¹⁸F-FDG PET/CT at the initial diagnosis and were clinically and pathologically diagnosed from January 1,2015to December 31,2020 in Second Hospital of Anhui Medical University were retrospectively analyzed,including general data,laboratory data,and PET/CT data of the patients,and the patients were followed up until June 30,2021.In this study,SPSS25.0 software was selected for statistical processing,the chi-square test was selected for measurement data analysis,non-parametric test was selected for grade data analysis,and receiver operating characteristic curve（ROC）was used to determine the optimal cutoff value.Survival curves were plotted using Kaplan-Meier,and univariate and multivariate analyses were performed for the analysis of prognostic factors to select independent affecting independent prognostic factors associated with prognosis,with P<0.05 considered statistically significant,and a novel prognostic risk model was constructed according to the influencing factors affecting OS of patients.Results:Of the 98 newly diagnosed MM patients,66（67.3%）were males and 32（32.7%）were females,with a male to female ratio of 2.06:1,the age was 66 years（42–89 years）.M protein typing was the most common Ig G type in 55 patients（56.1%）,followed by Ig A type in 25 patients（25.5%）.The distribution of patients with International Staging System（ISS）stage was 5 patients（5.1%）in stage I,35 patients（35.7%）in stage II,and 58 patients（59.2%）in stage III.After ¹⁸F-FDG PET/CT examination,bone destruction lesions were distributed throughout the body,and the most common site was the spine in 71 patients（72.4%）,and the incidence of extramedullary lesions was 17.3%.The presence of extramedullary lesions correlated with creatinine levels andβ2-microglobulin levels（P<0.05）.Statistical analysis revealed that the number of focal lesions≥3 was associated with DS stage,creatinine level,serum calcium and higher RCRP level（P<0.05）.Maximum standardized uptake value（SUVmax）≥7.85 had a correlation with ISS stage,creatinine level,andβ2-microglobulin（P<0.05）.In univariate Cox regression analysis,platelet,creatinine level,lactate dehydrogenase level,β2-microglobulin level,plasma cell ratio,number of focal lesions,extramedullary lesions,and SUVmax were factors predictive of PFS;creatinine,lactate dehydrogenase,extramedullary lesions,and SUVmax was factors predictive of OS.In multivariate Cox analysis,thrombocytopenia,elevated lactate dehydrogenase level,number of focal lesions≥3,and SUVmax≥7.85 were independent poor prognostic factors for PFS,and elevated lactate dehydrogenase level,elevatedβ2-microglobulin level,presence of extramedullary disease,and SUVmax≥7.85 were independent poor prognostic factors for OS.Four factors that were independently prognostic for OS:SUVmax,extramedullary disease,LDH,andβ2-microglobulin were included in the construction of a prognostic risk model to predict OS and PFS.98 patients were re-divided into two groups according to the hazard ratio score:high-risk group（36,36.7%）and low-risk group（62,63.3%）,and the OS and PFS of the high-risk group was found to be significantly shorter than those of the low-risk group by analysis（P<0.05）.The ability of this model to predict PFS and OS was better than that of DS stage,ISS stage,age and gender（P<0.05）.Conclusion:¹⁸F-FDG PET/CT can reflect the disease characteristics of MM,and its parameters SUVmax and the presence of extramedullary disease are closely related to the poor prognosis of patients with NDMM.The prognostic risk model constructed based on the combination of the two clinical parameters:β2-microglobulin and lactate dehydrogenase can effectively predict OS and PFS in NDMM and may be a potential prognostic tool for evaluating patients with MM.