Lack of survival improvement with novel anti-myeloma agents for patients with multiple myeloma and central nervous system involvement: the Greek Myeloma Study Group experience

Involvement of the central nervous system (CNS) is a rare complication of multiple myeloma (MM). Herein, we have described the incidence, characteristics, prognostic factors for post CNS-MM survival, and outcome of CNS-MM and explored the efficacy of novel agents (NA) (thalidomide, bortezomib, lenalidomide) in this setting. Between 2000 and 2013, 31 (0.9 %) out of 3408 newly diagnosed symptomatic MM patients, consecutively diagnosed and treated during the same period in 12 Greek centers, developed CNS-MM (M/F 15/16, median age 59 years, range 20-96 years; newly diagnosed/relapsed-refractory 2/29; median time to CNS-MM diagnosis 29 months). Clinical and laboratory characteristics were retrospectively recorded. Twenty-six percent of patients had circulating plasma cells (PCs) or plasma cell leukemia (PCL) at CNS-MM and 39 % had skull-derived plasmacytomas, suggesting hematological and contiguous spread. Treatment for CNS-MM was offered in 29/31 patients and 11/29 responded (NA 18/29, additional radiotherapy 9/28, intrathecal chemotherapy 13/29). The median post CNS-MM survival was 3 months (95 % CI 1.9-4.1) and did not differ between patients treated with NA and/or radiotherapy vs. others. In the multivariate analysis, prior treatment of MM with NA, extramedullary disease (EMD) during MM course (i.e., plasmacytomas, circulating PCs, or documented PCL) and abnormally high LDH at MM diagnosis were independent prognostic factors, whereas treatment of CNS-MM with NA did not predict for post CNS-MM survival. Despite the relatively limited number of patients due to the rarity of CNS-MM, our results suggest that NA do not seem to improve post CNS-MM survival. Patients with EMD display shortened post CNS-MM survival and should be followed thoroughly.