Therapeutic options in the management of myeloma bone disease

Impact of Natural Dietary Agents on Multiple Myeloma Prevention and Treatment: Molecular Insights and Potential for Clinical Translation

Chemoprevention is based on the use of non-toxic, pharmacologically active agents to prevent tumor progression. In this regard, natural dietary agents have been described by the most recent literature as promising tools for controlling onset and progression of malignancies. Extensive research has been so far performed to shed light on the effects of natural products on tumor growth and survival, disclosing the most relevant signal transduction pathways targeted by such compounds. Overall, anti-inflammatory, anti-oxidant and cytotoxic effects of dietary agents on tumor cells are supported either by results from epidemiological or animal studies and even by clinical trials. Multiple myeloma is a hematologic malignancy characterized by abnormal proliferation of bone marrow plasma cells and subsequent hypercalcemia, renal dysfunction, anemia, or bone disease, which remains incurable despite novel emerging therapeutic strategies. Notably, increasing evidence supports the capability of dietary natural compounds to antagonize multiple myeloma growth in preclinical models of the disease, underscoring their potential as candidate anti-cancer agents. In this review, we aim at summarizing findings on the anti-tumor activity of dietary natural products, focusing on their molecular mechanisms, which include inhibition of oncogenic signal transduction pathways and/or epigenetic modulating effects, along with their potential clinical applications against multiple myeloma and its related bone disease.

Long-term follow-up of patients with multiple myeloma treated with total body irradiation-Melphalan conditioning

BACKGROUND AND OBJECTIVES

Since a study published in 2002 showed a survival advantage of melphalan-only conditioning for stem cell transplantation (HSCT) over melphalan-total body irradiation (mel-TBI) in patients with multiple myeloma (MM), most centers abandoned mel-TBI. Mel-TBI causes more early toxicity and is more complicated to administer, but we speculated it may result in longer term survival with radiation as an independent treatment modality. Therefore, we analyzed the long-term outcome of patients with MM who received mel-TBI as part of conditioning at our center.

PATIENTS AND METHODS

From 1995 to 2013, 50 patients with MM underwent autologous HSCT at Tulane University Medical Center using mel-TBI conditioning. We used Kaplan-Meier survival analysis and compared our patients with data available from the Louisiana Tumor Registry.

RESULTS

The mean survival of our patients was 70.98 months from time of transplant and 84.2 months from time of initial diagnosis. No differences were observed according to gender, ethnicity, or age at transplant. The expected median survival in a population-based registry (matched for age and year of treatment) was 27 months (P<.001).

CONCLUSIONS

Total body irradiation in conjunction with melphalan as conditioning is feasible and can lead to long-term survival. More research is necessary to determine which patients benefit most. Mel-TBI should also be explored in conjunction with immunotherapy.

Systemic Therapy for Bone Metastases

Background

Accelerated bone loss in patients with cancer is a frequent problem that may result from invasion of the cancer to bone, paraneoplastic tumor proteins, and/or hormonal therapies utilized for cancer treatment. Patients with osteolytic bone disease from multiple myeloma and bone metastases from solid tumors may develop a vicious cycle of bone destruction involving both osteolytic and osteoblastic effects. Consequently, a variety of skeletal-related events (SREs) may occur, including pathological fractures, hypercalcemia, spinal cord compression, and the need for surgical intervention and radiation therapy.

Methods

This article reviews the results of trials that investigated the safety and efficacy of pharmacologic agents, including bisphosphonates and denosumab, for treatment of bone metastases. This analysis is derived from an assessment of the medical literature.

Results

Beneficial systemic therapies for bone metastases have been developed to decrease SREs. Possible antitumor effects of the bisphosphonates are explored. In addition, the utility of markers of bone turnover in relation to response to therapy and survival, the safety and toxicity of bone-targeted therapies, treatment guidelines, and economic considerations are also discussed.

Conclusions

Effective systemic therapies for metastatic bone disease are available. Ongoing and future research projects in this field are also presented.

Increased osteocyte death in multiple myeloma patients: role in myeloma-induced osteoclast formation

The involvement of osteocytes in multiple myeloma (MM)-induced osteoclast (OCL) formation and bone lesions is still unknown. Osteocytes regulate bone remodelling at least partially, as a result of their cell death triggering OCL recruitment. In this study, we found that the number of viable osteocytes was significantly smaller in MM patients than in healthy controls, and negatively correlated with the number of OCLs. Moreover, the MM patients with bone lesions had a significantly smaller number of viable osteocytes than those without, partly because of increased apoptosis. These findings were further confirmed by ultrastructural in vitro analyses of human preosteocyte cells cocultured with MM cells, which showed that MM cells increased preosteocyte death and apoptosis. A micro-array analysis showed that MM cells affect the transcriptional profiles of preosteocytes by upregulating the production of osteoclastogenic cytokines such as interleukin (IL)-11, and increasing their pro-osteoclastogenic properties. Finally, the osteocyte expression of IL-11 was higher in the MM patients with than in those without bone lesions. Our data suggest that MM patients are characterized by a reduced number of viable osteocytes related to the presence of bone lesions, and that this is involved in MM-induced OCL formation.

Three cases of bone metastases in patients with gastrointestinal stromal tumors

Gastrointestinal stromal tumors (GISTs) are rare, but represent the most common mesenchymal neoplasms of the gastrointestinal tract. Tumor resection is the treatment of choice for localized disease. Tyrosine kinase inhibitors (imatinib, sunitinib) are the standard therapy for metastatic or unresectable GISTs. GISTs usually metastasize to the liver and peritoneum. Bone metastases are uncommon. We describe three cases of bone metastases in patients with advanced GISTs: two women (82 and 54 years of age), and one man (62 years of age). Bones metastases involved the spine, pelvis and ribs in one patient, multiple vertebral bodies and pelvis in one, and the spine and iliac wings in the third case. The lesions presented a lytic pattern in all cases. Two patients presented with multiple bone metastases at the time of initial diagnosis and one patient after seven years during the follow-up period. This report describes the diagnosis and treatment of the lesions and may help clinicians to manage bones metastases in GIST patients.