Urinary N-telopeptide levels in multiple myeloma patients, correlation with Tc-99m-sestaMIBI scintigraphy and other biochemical markers of disease activity

Consensus on the utility of bone markers in the malignant bone disease setting

Biochemical markers of bone turnover provide insight into ongoing rates of skeletal metabolism and tumor-bone interactions in patients with malignant bone disease. This article reviews the available recent evidence assessing the potential of bone markers for detecting and monitoring malignant bone lesions in patients with advanced cancers, and for assessing overall skeletal health and response to antiresorptive therapies in patients at all stages of cancer progression. Most data thus far are for urinary N-terminal cross-linked telopeptide of type I collagen (NTX) in predicting risks of skeletal morbidity and death and monitoring response to zoledronic acid in patients with bone metastases. Ongoing studies are evaluating such correlations for other markers and therapies. Emerging evidence suggests that bone markers may help identify patients at high risk for bone metastasis or bone lesion progression, thereby allowing improved follow-up. Results from ongoing clinical trials evaluating such potential applications of bone markers are awaited.

Technetium-99m sestamibi scintigraphy is sensitive and specific for the staging and the follow-up of patients with multiple myeloma: a multicentre study on 397 scans

We evaluated the additional benefit of Technetium(99)-sestamibi (99mTc-MIBI) scanning in comparison with standard X-ray techniques for multiple myeloma patients either at diagnosis or during follow-up. Between February 2001 and January 2005, 397 whole body scans were acquired. On 229 scans performed at diagnosis, 146 (64%) were positive and 81 cases have discordant X-ray results. The sensitivity of 99mTc-MIBI and X-ray were 77% and 45% respectively. As a result of 99mTc-MIBI, 40% of asymptomatic myeloma patients were up-staged. The positivity of 99mTc-MIBI correlated significantly with all of the most relevant clinical and biological parameters. Multivariate analysis selected only high reactive C protein (P = 0.0005), bone marrow infiltration (P = 0.02) and bone pain (P = 0.002) as factors affecting 99mTc-MIBI pattern. In 22 patients with solitary myeloma, 99mTc-MIBI was positive in 86% of cases and detected more disease sites than X-ray. Among 168 scans performed during follow-up, 99mTc-MIBI presented high specificity in patients showing a complete response (CR; 86%), and correlated with myeloma activity and with response to therapy. At multivariate analysis, a positive pattern correlated with bone marrow infiltration (P = 0.002) and disease status other than CR (P = 0.03). We conclude that 99mTc-MIBI scanning is an additional diagnostic tool with a high specificity for the staging and the follow-up of multiple myeloma patients.

Relationship between serum levels of vascular endothelial growth factor, hepatocyte growth factor and matrix metalloproteinase-9 with biochemical markers of bone disease in multiple myeloma

BACKGROUND

Multiple myeloma is characterized by accumulation of plasma cells in the bone marrow, with osteolysis and increased marrow angiogenesis. We studied molecules involved in angiogenesis (MMP-9, HGF, VEGF) in relation to disease stage, extent of bone destruction, and markers of bone turnover (Ntx and PICP).

METHODS

MMP-9, HGF, VEGF were measured in the serum of 42 newly diagnosed myeloma patients and 24 controls with commercial ELISA kits. Urinary levels of Ntx were measured by ELISA, and serum PICP with RIA. Extent of radiological bone disease was graded into low and high score. Stage was estimated according to the Durie-Salmon criteria.

RESULTS

HGF, VEGF and Ntx were higher in patients than controls (p<0.001). MMP-9 and PICP did not differ between patients and controls. HGF, VEGF, MMP-9 and Ntx increased significantly with disease stage (I to III, p<0.001) and PICP decreased significantly with advancing stage (p<0.05). There was a positive correlation between HGF and MMP-9 (r: 0.36, p<0.01), VEGF and MMP-9 (r: 0.38, p<0.01), Ntx and MMP-9 (r: 0.39, p<0.01) and an inverse correlation between PICP and MMP-9 (r: -0.66, p<0.0001).

CONCLUSIONS

Angiogenesis and bone destruction are closely interrelated in myeloma, and cytokine levels (MMP-9, VEGF and HGF) may be useful in monitoring progression.

Treatment for Myeloma Bone Disease: Table 1

Multiple myeloma (MM) is a B cell malignancy characterized by enhanced bone loss commonly associated with diffuse osteopenia, focal lytic lesions, pathologic fractures, hypercalcemia, and bony pain. Bone destruction in MM results from asynchronous bone turnover wherein increased osteoclastic bone resorption is not accompanied by a comparable increase in bone formation. Consequently, patients with MM frequently require radiation therapy, surgery, and analgesic medications. The recent development of minimally invasive surgical procedures such as kyphoplasty allows patients with myeloma with vertebral compression fractures to have immediate improvement in their quality of life with shorter hospital stays. Bisphosphonates are specific inhibitors of osteoclastic activity, and these agents have been evaluated in patients with MM with bone disease during the past 15 years. Monthly i.v. infusions of either pamidronate or zoledronic acid have reduced the skeletal complications among patients with MM and are now a mainstay of myeloma therapy. Orally administered bisphosphonates, in contrast, have shown little ability to slow the development of skeletal complications in these patients. Although preclinical studies suggest that nitrogen-containing bisphosphonates have potent antitumor effects, clinical trials will be necessary, probably at higher doses given more slowly, to establish their possible antitumor effects clinically. Moreover, recent advances in the use of bone-seeking radiopharmaceuticals make these attractive therapeutic candidates to combine with bisphosphonates or radiosensitizing drugs (e.g., bortezomib) to achieve a synergistic effect. As our understanding of the pathophysiology of myeloma bone disease continues to grow, new target therapies will continue to emerge, offering new and more advanced options for the management of myeloma bone disease.

Myeloma bone disease

The major clinical manifestation of multiple myeloma is related to the osteolytic bone destruction. The bone disease can lead to pathologic fractures, spinal cord compression, hypercalcemia, and pain. It is also a major cause of morbidity and mortality in these patients. These patients frequently require radiation therapy, surgery and analgesic medications. Bisphosphonates are specific inhibitors of osteoclastic activity, and these agents have been evaluated in myeloma patients with bone disease during the past 15 years. Several large randomized trials have been conducted in myeloma patients also receiving chemotherapy. Orally administered bisphosphonates have shown little ability to slow the development of skeletal complications in these patients. In contrast, more potent intravenous monthly infusions of either pamidronate or zoledronic acid have reduced the skeletal complications among these patients and are now a mainstay of myeloma therapy. A number of other types of new anti-bone-resorptive agents are also in early clinical development.

The role of markers of bone remodeling in multiple myeloma

Osteolytic bone disease is a frequent complication of multiple myeloma, resulting in skeletal complications that are a significant cause of morbidity and mortality. A characteristic feature of myeloma bone disease is that the lesions rarely heal and bone scans are often negative in myeloma patients who have extensive lytic lesions, offering very little in the follow-up of bone disease. X-rays are also of limited value in monitoring bone destruction during anti-myeloma or anti-resorptive treatment. Biochemical markers of bone turnover, such as N- and C-terminal cross-linking telopeptide of type I collagen (NTX, CTX/ICTP, respectively), and newer ones such as the tartrate resistant acid phosphatase isoform 5b, provide information on bone dynamics that in turn may reflect disease activity in bone. Several studies have shown bone markers to be elevated in myeloma patients and reflect the extent of bone disease, while in some of them bone resorption markers correlate with survival. These markers may also be helpful in identifying those patients likely to respond to bisphosphonate treatment, and monitoring the effectiveness of bisphosphonate therapy in the management of myeloma bone disease. This review attempts to summarize the existing data for the role of markers of bone remodeling in assessing the extent of bone destruction in myeloma and monitoring bone turnover during specific anti-myeloma treatment. We also discuss some novel markers that may be of particular interest in the near future.

Systemic levels of interleukin-6 and matrix metalloproteinase-9 in patients with multiple myeloma may be useful as prognostic indexes of bone disease

Multiple myeloma is characterized by accelerated production of the proteolytic enzyme matrix metalloproteinase (MMP)-9. We hypothesized that myeloma-produced MMP-9 may influence the rate of bone turnover in a paracrine manner. Thus, we examined the correlations of MMP-9 levels, disease severity, and bone turnover rate as evaluated by markers of bone formation and resorption.

Thirty-seven newly diagnosed multiple myeloma patients (nine of Durie-Salmon stage I, 12 of stage II and 16 of stage III) and 12 age-matched controls were studied. Serum MMP-9 levels were significantly higher at stage II compared to stage I (188.78±91.27 vs. 59.25±33.09 ng/mL, p<0.004). Additionally, free urine pyridinolines (F-Pyd), free urine deoxy-pyridinolines (F-Dpd) and urine N-telopeptide fragment (NTx) were elevated, their level correlating with disease stage (p<0.001, p<0.03, p<0.001, respectively), as were bone marrow infiltration and serum interleukin-6 (IL-6) levels (p<0.0001, p<0.01, respectively). MMP-9 levels were lower in patients compared with controls (p<0.001), whereas IL-6 and bone resorption marker levels were higher in patients than in controls (p<0.001 in all cases). Significant correlation was found between infiltration, MMP-9, free urine pyd, free urine dpd and NTx for each stage of the disease (p<0.03, p<0.003, p<0.002, p<0.003 and p<0.001, respectively). Levels of MMP-9 and of IL-6 in multiple myeloma correlate well with bone turnover rate and may be useful in disease evaluation.