Spinal lesions in multiple myeloma: Primary bone tumors with distinct prognostic factors

Purpose: Although prognostic factors of spinal multiple myeloma (MM) seem to differ from those of other spine metastases (SpM), the data in the literature remains scarce.

Methods: A prospective population of 361 patients treated for spine MM lesions between January 2014 and 2017.

Results: OS for our series was 59.6 months (SD 6.0 months; CI 95%: 47.7-71.3). Cox multivariate proportional-hazards analysis showed that bone marrow transplant [HR: 0.390, 95% CI 0.264-0.577; p < 0.0001] and light-chain isotype [HR: 0.748, 95% CI 0.318-1.759; p = 0.005] were independent predictors of longer survival. In contrast, age >80 years [HR: 2.7, 95% CI 1.6-4.3; p < 0.0001], ISS III [HR: 2.510, 95% CI 2.01-3.124; p = 0.001], IgA isotype [HR: 1.475, 95% CI 1.031-2.11; p = 0.034] and IgD/M isotype [HR: 2.753, 95% CI 1.230-6.130; p = 0.013] were independent poor prognostic factors. However, ECOG (p = 0.486), spine surgery (p = 0.391), spine radiotherapy (p = 0.260), epidural involvement (p = 0.259), the number of vertebra lesions (p = 0.222), and synchronous/metachronous timeline (p = 0.412) were not significantly associated with improved OS.

Conclusions: Spinal involvement in the context of MM does not influence OS. The main prognostic factors to consider before spinal surgery are the characteristics of the primary MM disease (ISS score, IgG isotype and systemic treatment).