(PA-369) Prior Plasma Cell Dyscrasia Is Associated with Lower Odds of Severe Myeloma-defining Events at Diagnosis

Introduction: Clinical guidelines recommend indefinite monitoring of patients with asymptomatic precursor plasma cell disorders (MGUS or smoldering multiple myeloma [SMM]), yet this practice is not grounded in high-quality evidence. Whether such surveillance meaningfully influences clinical outcomes at the time of multiple myeloma (MM) diagnosis remains uncertain. The primary aim of this study was to evaluate differences in symptom burden and healthcare utilization at MM diagnosis between patients with and without a known prior plasma cell disorder (pPCD).

Methods: We retrospectively reviewed all patients diagnosed with multiple myeloma (MM) between January 2019 and July 2024 at our institution. Patients with a known prior plasma cell disorder (pPCD)—MGUS, smoldering MM, or solitary plasmacytoma—diagnosed ≥3 months before MM were identified. Those with systemic AL amyloidosis or prior plasma cell–directed therapy were excluded. Myeloma-defining events (MDEs) included IMWG 2014 CRAB and SLiM criteria. Healthcare utilization, time from symptom onset to diagnosis, and emergency visits were captured through manual chart review. Logistic regression models were adjusted for age and sex, and descriptive statistics were used to compare the MDE at diagnosis.

Results: Among 424 patients, 104 had pPCD (n=71 MGUS, n=25 smoldering MM, n=8 solitary plasmacytoma) and 320 had MM without a known pPCD (nPCD). Median time from pPCD to MM diagnosis was 4.6 years. Patients with pPCD had fewer CRAB features at diagnosis (71% vs 92%) and shorter time from symptom onset to diagnosis (4.8 vs 7.6 months, p< 0.001). Anemia (38% vs 65%), renal failure (11% vs 23%), bone lesions (44% vs 59%), and PRBC transfusions (16% vs 39%) were less frequent in the pPCD group compared to nPCD. ER visits within 3 months of diagnosis were also lower in pPCD patients (36% vs 64%).

On multivariable analysis, pPCD significantly reduced the odds of presenting with a composite adverse outcome—dialysis, fracture, hospital admission, cord compression, hypercalcemia treatment, or transfusion—by 73% (OR 0.27, 95% CI 0.16–0.43, p< 0.001). This association persisted after excluding patients without hematology follow-up within 1 year of presentation.

Conclusions:

This study demonstrates that patients with a prior PCD present with fewer MDE and lower acute healthcare utilization at the time of MM diagnosis. While our findings do not define optimal follow-up intervals, they support the clinical value of ongoing surveillance in patients with pPCD. These results contribute to the growing body of evidence suggesting that early recognition and monitoring may attenuate disease-related morbidity at presentation. Ongoing prospective studies such as iSTOP-MM will be critical in determining the broader impact of MGUS screening and longitudinal follow-up.