Multiple Myeloma: Real-world Data on the Clinical Presentation and Outcomes From Oman

There is a paucity of data on multiple myeloma (MM) from Oman and the region. This study reports the clinical presentation and survival outcomes in Omani patients with MM at Sultan Qaboos University Hospital (SQUH), a tertiary care academic center.

This retrospective included all patients diagnosed, treated, and followed up for MM at SQUH between June 2008 and December 2018. Patient demographics, disease characteristics, clinical presentation, prognostic parameters, and survival data were obtained from the patients' electronic medical records. The Kaplan-Meier method was used to estimate the progression-free survival (PFS) and overall survival (OS), and the log-rank test was used to compare survival according to the international staging system (ISS) stage.

Ninety-eight patients were analyzed, 49 (50%) of whom were males. The median age was 61 years (range: 30-88). Immunoglobulin G (IgG) was the most common subtype of myeloma (59.6%), followed by IgA (24.2%) and IgD (4%). Twelve patients (12%) had light chain myeloma. The most common manifestation of myeloma at the time of initial diagnosis was anemia (50%), followed by lytic lesions (41.5%), renal insufficiency (24.2%), and hypercalcemia (23.2%). Forty-three patients (44%) had ISS stage III disease at presentation. Over the study period, patients received different types of induction therapy. Ninety patients received therapy at SQUH and had complete data on first-line treatment. Thirty-six patients (41%) received proteasome inhibitor (PI) based regimens, 23 patients (25%) had immunomodulatory-based (IMID-based) therapy, and 23 patients (25%) had combination PI and IMiD-based induction therapy. For patients with complete data on treatment, responses and outcome (n = 90), after a median follow-up of 76 months (95% confidence interval [CI]: 54-97 m), median PFS was 59 months (95% CI: 20.1-78), with an estimated five year PFS of 41%. Median OS was 109 months (95% CI: 65-173) with a 5-year OS of 61%. ISS stage predicted OS (ISS stage I and stage II: 133 m, 95% CI: 94-173 m, stage III: 36 m, 95% CI: 25-47 m; log-rank p < 0.001) but not PFS.

The median age of our patients is younger than what is published in the literature. Most of our patients presented with advanced-stage disease, which was predictive of survival in our cohort. The lack of uniformity of treatment and the small number of patients precluded concluding the effect of treatment on survival. Collaboration with other centers in Oman and the region to collect retrospective and prospective data on a larger cohort of patients is recommended.

The authors have confirmed that clinical trial registration is not needed for this submission.