Clinical and Prognostic Relevance of Magnetic Resonance Imaging of the Spine in Newly Diagnosed Multiple Myeloma Patients Receiving Autologous Stem Cell Transplantation.

Magnetic resonance imaging (MRI) of the spine has demonstrated to be a useful tool for correct staging of multiple myeloma (MM), as it is more sensitive than plain x-rays in detecting vertebral lesions. Furthermore, different patterns of bone marrow involvement (focal, diffuse or normal) can be depicted, and this could contribute to better define the prognosis in newly diagnosed patients. In the present study we prospectively evaluated the clinical and prognostic role of spinal MRI in 120 newly diagnosed MM patients (68M, 52F, median age = 56yrs) that subsequently received high-dose chemotherapy and autologous stem cell transplantion, either single (n=28) or double (n=92). Pattern of marrow involvement was focal in 72 cases (60%), diffuse in 29 (24%) and negative in 19 (16%). Patients with a diffuse pattern showed a significantly higher bone marrow plasma cell infiltration (p=0.05) and beta2 microglobulin values (p= 0.04) as compared to patients with a focal pattern; stage III disease according to ISS was observed in 29%, 8% and 1% of patients with a diffuse, focal or negative pattern, respectively. Response rate to treatment program was similar in the three groups of patients, with a stringently defined CR obtained in 34% of patients with a focal pattern, 29% in those with a diffuse pattern and 35% in patients with a negative MRI. Median progression-free survival showed a trend in favor of patients with a negative MRI (54 months) as compared to those with a focal or diffuse pattern (42 and 38 months, respectively). A focal pattern of bone marrow involvement was associated with a significantly higher probability of experiencing an overt vertebral lesion (73% vs 48% in patients with diffuse pattern, p=0.03), including either a compression fracture or a vertebral mass. Consistently with this finding, also extra-spinal bone lesions were more common in patients with a focal pattern (66%) as compared to patients with a diffuse or negative pattern (42% and 6% respectively) (p=0.05). Serum crosslaps were significantly increased in patients with a focal pattern (7032 pmol/L±635SE vs 5431pmol/L±812SE in those with a diffuse pattern, p=0.04). According to our data, a diffuse pattern of bone marrow involvement could be predictive of a more aggressive disease, even though these data needs to be confirmed in a larger series of patients. A focal pattern of bone marrow involvement at diagnosis could help to identify MM patients more prone to develop skeletal complications, so that a careful monitoring and bisphosphonate therapy should be recommended.