Diagnostic relevance of 2-[18 F]-FDG PET/CT in patients recently diagnosed with monoclonal gammopathy of undetermined significance.

2-[18 F]-FDG PET/CT is a useful diagnostic technique to assess bone and soft tissue disease in multiple myeloma (MM) but is not recommended by the International Myeloma Working Group for the evaluation of monoclonal gammopathy of undetermined significance (MGUS). The objective of this study was to evaluate the role of 2-[18 F]-FDG PET/CT in the management of these patients. An observational retrospective study was conducted on 338 patients with MGUS who underwent 2-[18 F]-FDG PET/CT. The mean age was 70.80 ± 11.84 years, and 69.2% of patients had cardiovascular risk factors. Patients were classified according to their progression risk (Mayo Clinic). The mean post-diagnosis follow-up was 8.35 ± 14.46 months. Pathological findings were recorded in 49 patients: 30 with myeloma bone lesions (15 in the initial study and 15 in follow-up) and 19 with other neoplastic (n = 13) or pathologically significant findings (n = 6). Body mass index, monoclonal component rate (MCR) > 1 g/dL and ≥1 risk factors for MM were significant in univariate logistic regression analyses. The MCR emerged as the main predictor of a positive 2-[18 F]-FDG PET/CT in adjusted multivariate regression analysis, with an area under the receiver operating characteristic curve of 0.785 and cutoff for optimal sensitivity/specificity of 1.0 ng/mL (71.4% sensitivity, 71.2% specificity). 2-[18 F]-FDG PET/CT results correctly classify patients with MGUS and could improve the detection of bone lesions over existing techniques, with the additional possibility of detecting neoplastic processes. The best parameter to predict a positive 2-[18 F]-FDG PET/CT was the MCR.

Impact of bone events on survival in solitary bone plasmacytoma.

BACKGROUND: Although much studied in multiple myeloma, bone events (BE) can also cause important morbidity in bone plasmacytoma patients. To our knowledge, the effect of BE on overall survival (OS) and progression to multiple myeloma free-survival (MPFS) also has never been studied. PATIENTS AND METHODS: Fifty-nine patients treated from 2008 to 2017 were retrospectively assessed. All patients had histological proof of disease and were treated with radical radiotherapy (RT). Available clinical information for at least 6 months follow-up or until death had to be available. BE were described as one of the following events in the index bone: fractures, osteomyelitis, chronic pain, surgery or loss of limb function after RT. RESULTS: Mean age at diagnosis was 57.3 years (18-80); most male (67.8%). Mean OS, bone event free-survival (BEFS), local progression-free survival (LPFS) and MPFS were 41, 36, 37 and 19 months, respectively. There were 15 deaths. BEFS (p = 0.008) and age>55y (p = 0.044) were associated with MPFS. Only BEFS correlated with OS (p = 0.029). BE was independently associated with both MPFS and OS in multivariate analysis. CONCLUSION: BE and survival end-points were correlated. BE should be investigated in prospective trials.

Clinical features and prognostic factors in solitary plasmacytoma.

This study aimed to review the clinical features and outcome of 53 patients with solitary plasmacytoma managed at our Institution between 1976 and 2012. Thirty-five patients had bone solitary plasmacytoma and 18 extramedullary solitary plasmacytoma. Tumour sizes were larger in patients with bone involvement (P = 0·003). Treatment consisted of local radiotherapy (n = 26), radiotherapy + chemotherapy (n = 15), surgery (n = 4) and chemotherapy (n = 8); the local control rate was 94·3%. Progression to multiple myeloma was recorded in 20/35 (57·1%) patients with bone involvement and in 1/18 (5·5%) patients with extramedullary disease (P = 0·0003). The 5-year overall survival (OS) rate was 78·4%; bone solitary plasmacytoma patients had a significantly worse OS (71·9% vs. 88·2%, respectively; P = 0·029) and 5-year progression-free survival (PFS; 53·0% vs. 88·5%; P = 0·0003) compared to extramedullary solitary plasmacytoma patients. On univariate analysis, bone disease and size (≥5 cm) impacted negatively on PFS (P = 0·0027 and P = 0·04, respectively). Bone disease also affected OS (P = 0·04). In multivariate analysis bone location was the only independent prognostic factor for PFS (P = 0·0041) and OS (P = 0·021). Patients with bone solitary plasmacytoma have a significantly worse prognosis than extramedullary solitary plasmacytoma cases.