Treatment Modalities and Outcomes of Multiple Myeloma Patients with Spinal Cord Compression: A Single Center Experience

Background: Spinal cord compression (SCC) is a devastating complication of multiple myeloma (MM). Data regarding optimal management are scarce.

Methods: A single center retrospective analysis of MM patients (pts) with SCC. All consecutive MM pts' files from 1.1.2016 to 30.12.2021 were manually screened to identify events with unequivocal radiologic evidence for SCC. The degree of neurological disability was stratified according to the modified spinal cord injury measure (mSCIM) score. Treatment modalities included decompression surgery, urgent radiation and urgent initiation of anti-MM therapy as a measure to improve neurological outcome. Neurological outcome was assessed 30 days and 6 months (mo) after presentation. Favorable neurological outcome was defined as improvement for pts presented with neurological dysfunction and as no deterioration for pts without neurological dysfunction. Treatment related adverse events (AEs) were evaluated 30 days after initiation of therapy for SCC (surgery or medications) or 30 days from end of radiotherapy.

Results: Records of 556 consecutive MM pts diagnosed with MM or solitary plasmacytoma were scanned. 31 events of SCC in 30 pts (5%) were identified. 5 pts had insufficient data for neurological improvement assessment. 25 (83%) pts had multiple myeloma and 5 (17%) pts had solitary plasmacytoma, 2 of them progressed to multiple myeloma later. The median age at the time of the SCC event was 69.7 (range 40-89) years. 21 (68%) were males. 19% had high risk cytogenetics. 17/26 (65%) events happened at the time of MM presentation and 9 (35%) events at relapse, 8 of them while receiving anti myeloma treatment. For relapsed pts, the SCC event happened at the 3^rd relapse (median, range 1-5). The median number of involved vertebrae was 1.5 [range 1-7]. The most common site was the thoracic spine (21/26, 81%). 23/25 (92%) had pain at the time of the event, and 14/24 (58%) evaluable pts had neurological deficit.

Out of 26 SCC events, 12 were treated with urgent radiation (46%), 12 (46%) underwent surgery and 13 (50%) pts were treated with urgent anti-MM therapy. 11 pts were treated with more than 1 modality. 9 pts received proteasome inhibitors (PIs) based therapy (8 bortezomib and 1 carfilzomib), 2 pts received chemotherapy (one combined with PIs), and 1 patient each was treated with daratumumab and belantamab. The median time from onset of neurological symptoms to (any) treatment initiation was 7 (range 0-243) days. There were no differences in pts' age and baseline neurological function between pts treated with surgery, radiation or systemic therapy.

Favorable neurological outcome was observed in 14/22 (63%) of evaluable pts at 30 days and in 14/18 (78%) of evaluable pts at 6 mo. 3 pts without improvement at 30 days improved at 6 mo. None of the pts with favorable outcome at 30 days deteriorated at 6 mo. Age, sex, mSCIM at presentation, modality of treatment and time from neurological symptoms to treatment initiation did not correlate with neurological outcome.

The median follow-up was 56.5 (95% CI 43.6-69.4) mo. The median overall survival time (OS) of the entire cohort from SCC event was 58.5 (95% CI 24.1-93.0) mo. The median OS for pts diagnosed with SCC at initial presentation and at relapse was 86.1 (95% CI not applicable) and 5.0 (95% CI 0-18.86) mo, respectively. SCC had no effect on OS from diagnosis (80.4 mo for pts with SCC vs. 91.7 mo for pts without SCC, p=0.27). Favorable neurological outcome at 6 mo, but not at 30 days, was associated with prolonged OS (median 86.1 vs 34.8 mo, p=0.004).

Grade (Gr)≥3 AEs for pts who underwent surgery (n=11 for evaluable pts) included 2 peri-surgical bleeding and 1 gastrointestinal bleeding. For the anti-MM therapy group (n=12), Gr≥3 AEs included 3 infections (including 1 fatal), 4 cases of neutropenia, 3 cases of thrombocytopenia (Gr≥3), and 1 case each of heart failure, cyto-megalovirus reactivation, mucositis and anemia. No Gr≥3 AEs were recorded in pts (n=11) following radiation.

Conclusions: SCC is a rare but serious complication of MM. Newly diagnosed pts presenting with SCC have similar OS compared with their “non-SCC” counterparts, whereas pts with SCC event at the time of relapse appear to have dismal prognosis. Failure to achieve a favorable neurological outcome is associated with decreased survival, emphasizing the need for larger clinical trials to guide optimal management and decision-making.

Mittelman:Novartis: Research Funding; Abbvie: Research Funding; FibroGen: Other: Speaker; BioConvergence: Consultancy; Dr. Reddy: Consultancy; Roche: Research Funding; CannaLean: Other: Shares; Johnson & Johnson: Research Funding; BMS: Research Funding. Avivi:ABBVIE: Consultancy; NOVARTIS: Consultancy.