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The predictive value of serum myeloma protein in solitary plasmacytoma
Won Ick Chang1, Hyeon Kang Koh2, Sung-Soo Yoon3
1Department of Radiation Oncology, Seoul National University College of Medicine, Seoul, Korea.
Purpose:
To identify the clinical usefulness of serum M protein and to establish a rationale for regular follow-up with serum protein electrophoresis in solitary plasmacytoma.
Materials And Methods:
Sixty-nine patients with solitary plasmacytoma and solitary plasmacytoma with minimal marrow involvement according to the International Myeloma Working Group criteria were retrospectively reviewed.
Results:
At a median follow-up of 6.2 years, 5-year local control (LC), 5-year multiple myeloma-free survival (MMFS), 5-year failure-free survival (FFS), and 5-year overall survival (OS) were 82.6%, 44.1%, 41.8%, and 85.1%, respectively. Among the patients whose initial serum M protein was present or not evaluated, 37.3% of patients showed disappearance of serum M protein after various treatment. MMFS of these patients were comparable to non-secretory plasmacytoma with undetectable levels of M protein, and significantly better than patients with persistent M protein. Increase of serum M protein ≥0.1 g/dL was most predictive of treatment failure with area under the curve of 0.731.
Conclusion:
Patients who eventually showed persistence of serum M protein after treatment showed worse MMFS and FFS compared to those whose serum M protein disappeared or who had initially non-secretory disease. The increase of serum M protein level ≥0.1 g/dL from current nadir was predictive of treatment failure. Therefore, regular follow-up with serum M protein is highly recommended especially unless the patient had initially non-secretory disease.
Insights
Serum M protein monitoring is crucial for solitary plasmacytoma patients. Persistence or increase of M protein predicts worse outcomes, highlighting the need for regular serum protein electrophoresis follow-up.
Area of Science:
- Hematology
- Oncology
- Clinical Chemistry
Background:
- Solitary plasmacytoma is a plasma cell disorder.
- Serum M protein is a key biomarker in plasma cell disorders.
- Understanding M protein dynamics is vital for treatment monitoring.
Purpose of the Study:
- To assess the clinical utility of serum M protein in solitary plasmacytoma.
- To establish the rationale for routine serum protein electrophoresis (SPEP) follow-up.
- To correlate M protein levels with patient outcomes.
Main Methods:
- Retrospective review of 69 patients with solitary plasmacytoma.
- Analysis of clinical data including local control, multiple myeloma-free survival (MMFS), failure-free survival (FFS), and overall survival (OS).
- Evaluation of serum M protein levels pre- and post-treatment.
Main Results:
- Five-year survival rates: LC 82.6%, MMFS 44.1%, FFS 41.8%, OS 85.1%.
- 37.3% of patients achieved M protein disappearance post-treatment, showing comparable MMFS to non-secretory cases.
- Persistent M protein correlated with worse MMFS and FFS; an increase ≥0.1 g/dL predicted treatment failure (AUC 0.731).
Conclusions:
- Persistence of serum M protein post-treatment is associated with poorer MMFS and FFS.
- An increase in serum M protein level ≥0.1 g/dL is a predictor of treatment failure.
- Regular serum M protein monitoring via SPEP is recommended for solitary plasmacytoma patients, except those with initially non-secretory disease.
