The incidence of venous thromboembolism (VTE) is more than 1 per thousand annually in the general population and increases further in cancer patients. The risk of VTE is higher in multiple myeloma (MM) patients who receive thalidomide or lenalidomide, especially in combination with dexamethasone or chemotherapy. Various VTE prophylaxis strategies, such as low-molecular-weight heparin (LMWH), warfarin or aspirin, have been investigated in small, uncontrolled clinical studies. This manuscript summarizes the available evidence and recommends a prophylaxis strategy according to a risk-assessment model. Individual risk factors for thrombosis associated with thalidomide/lenalidomide-based therapy include age, history of VTE, central venous catheter, comorbidities (infections, diabetes, cardiac disease), immobilization, surgery and inherited thrombophilia. Myeloma-related risk factors include diagnosis and hyperviscosity. VTE is very high in patients who receive high-dose dexamethasone, doxorubicin or multiagent chemotherapy in combination with thalidomide or lenalidomide, but not with bortezomib. The panel recommends aspirin for patients with < or = 1 risk factor for VTE. LMWH (equivalent to enoxaparin 40 mg per day) is recommended for those with two or more individual/myeloma-related risk factors. LMWH is also recommended for all patients receiving concurrent high-dose dexamethasone or doxorubicin. Full-dose warfarin targeting a therapeutic INR of 2-3 is an alternative to LMWH, although there are limited data in the literature with this strategy. In the absence of clear data from randomized studies as a foundation for recommendations, many of the following proposed strategies are the results of common sense or derive from the extrapolation of data from many studies not specifically designed to answer these questions. Further investigation is needed to define the best VTE prophylaxis.

No reports of the incidence rates for primary systemic amyloidosis (AL) have come to our attention. Records of all residents of Olmstead County, Minnesota, with a diagnosis of amyloidosis were obtained from the Mayo Clinic and its affiliated hospitals, as well as other medical groups that might have seen local patients for the period January 1, 1950 to December 31, 1989. Twenty-one patients fulfilled the criteria for the diagnosis of AL. The median age was 73.5 years, and 62% were men. In all but one patient the diagnosis was made ante mortem. The clinical data of the 21 patients were similar to those referral patients with AL seen at Mayo Clinic. Immunohistochemical stains were positive for monoclonal light chains in the amyloid deposits in 15 of the 21 cases. In six cases, tissue was not available for immunohistochemical studies. Three of the six patients without immunohistochemical stains had a free monoclonal lambda light chain in the urine, and the other three had a monoclonal serum protein. Immunoelectrophoresis/immunofixation detected a monoclonal (M)-protein in the serum of 16 of 17 patients tested. A monoclonal light chain was found in the urine of 10 of 15 patients. The overall sex- and age- adjusted rate per million person-years was 6.1 from 1950 to 1969 and 10.5 from 1970 to 1989. The similarity of these rates suggests no significant increase over time.

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We classified 100 cases of myeloma before chemotherapy as mature (28), intermediate (38), immature (19), or plasmablastic (15). The plasmablastic group had an estimated median survival (Kaplan-Meier method) of ten months, compared to 35 months for the other types (P less than .05). Decreased survival in the plasmablastic group was due to more frequent deaths in the first six months. There were no significant differences in survival among the mature, intermediate, and immature groups or among patients with different morphological grade or asynchrony scores. The plasmablastic myeloma group had more frequent renal insufficiency and higher plasma cell labeling indices, which may have contributed to the shorter survival.

The blood of most patients with active multiple myeloma (MM) contains cells related to the bone marrow tumor. However, identifying clonal cells in the blood of patients with monoclonal gammopathy of undetermined significance (MGUS) has been difficult. In this study, we analyzed blood mononuclear cells (BMNCs) from 16 patients with MGUS, 2 with amyloidosis, 8 with smoldering MM (SMM), 2 with indolent MM (IMM), and 15 with active MM using three different methods to detect and quantitate clonal cells, ie, immunofluorescence microscopy (IM) for monoclonal plasma cells, three-color flow cytometry (FC) for CD38(+)CD45- CD45(dim) cells, and the allele-specific oligonucleotide polymerase chain reaction (ASO-PCR). Using ASO-PCR, we were able to detect clonal cells in the blood in 13 of 16 patients with MGUS, 2 of 2 with amyloid, 6 of 8 with SMM, 2 of 2 with IMM, and 13 of 15 with MM. In 9 of the 13 patients with MGUS with blood involvement, the number of clonal cells was very small ( < 0.04% of the BMNCs). The median percentage of clonal cells as determined by ASO-PCR was 0.02 for MGUS, 0.02 for SMM, and 0.24 for MM. Clonal plasma cells or CD38+CD45- CD45(dim) cells were identified by IM or FC in 6 of 16 MGUS patients, 4 of 8 with SMM, and 11 of 15 with MM. In all cases in which IM or FC detected clonal cells, the ASO-PCR was positive. This study shows that, by using ASO-PCR, clonal cells can be found at very low levels in the blood in most patients with MGUS. However, the number of clonal cells in the blood of MGUS patients is less than those with overt MM (P = .006). In contrast to MGUS, patients with active MM are more likely to have identifiable clonal circulating plasma cells (P = .05).