Purpose: The aim of this study was to evaluate the significance of free light chains ratio (FLC ratio) as a prognostic factor for remission, progression and survival in patients with multiple myeloma (MM) and primary amyloidosis.
Methods: The concentrations of immunoglobulins and FLC ratio were measured using immunonephelometry. A total of 101 patients from 3 different disease groups were investigated during a 7-year period: 1) MM (n=95); 2) nonsecretory multiple myeloma (NSMM) (n=3); and 3) primary amyloidosis (n=3). Reference range for FLC ratio was 0.26-1.65.
Results: According to the International Staging System (ISS) for MM, abnormal serum FLC ratio was < 0.03 or > 32. Patients with MM and highly or intermediately abnormal FLC ratio and a combination of adverse risk factors (56.9%) had median survival of 26 months (range 16-38), as opposed to patients with normal or slightly changed values of FLC ratio without adverse risk factors (43.1%) with median survival of 45 months (range 27-69). Also, all of the patients with NSMM had slightly changed values of FLC ratio corresponding to low risk of disease progression. In patients with primary amyloidosis, 33.3% had slightly changed values of FLC ratio corresponding to low risk of disease progression, as opposed to 66.7% with abnormal FLC ratio, corresponding to high risk.
Conclusion: Abnormal FLC ratio in the examined groups could be an independent risk factor of disease progression and worse prognosis.