Researchers investigated the prognostic value of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) in patients with multiple myeloma (MM)

 

Multiple myelomas (MM) is a major primary bone neoplasm in adults characterized by malignant proliferation of plasma cells in bone marrow (BM), which results in a wide range of bone abnormalities.

Bone lesions and related symptoms or signs are major clinical features of MM, suggesting that evaluation of the whole-body skeleton is essential for the diagnosis, staging, and assessment of treatment response in MM patients.

Radiography

Plain radiography is universally available and relatively inexpensive, and therefore, used as a conventional imaging modality for the skeletal survey in patients with MM.

Subjects were 76 patients with newly diagnosed myeloma and pretreatment with 18F-FDG PET/CT from four hospitals. The PET/CT features were evaluated and the clinical characteristics were reviewed. Prognostic factors related to poor progression-free survival (PFS) and overall survival (OS) were identified using a Cox proportional hazards regression model and a prediction scale was developed based on the identified factors.

Multivariate analysis showed that the presence of 18F-FDG-avid focal bone lesions (≥ 3) was a significant and independent predictor of PFS (hazard ratio [HR] = 3.28, p = 0.007) and OS (HR = 11.78, p = 0.001). The presence of extramedullary disease on PET/CT scan was also a significant predictor of poor PFS (HR = 2.79, p = 0.006) and OS (HR = 3.89, p = 0.003).

A prognostic scale was developed using these two predictors. An increase in score on the scale corresponded to a significantly increased risk of poor OS (p = 0.005). Also, Kaplan-Meier analysis demonstrated that patient survival varied considerably according to the scale (p < 0.001 for OS and p = 0.001 for PFS).

The present study showed that the presence of three or more 18F-FDG-avid focal bone lesions and extramedullary disease were independent parameters associated with poor prognosis in patients with MM. Patients with three or more 18F-FDG-avid lesions and extramedullary illness on PET scan showed significantly shorter OS.

Also, the prognostic scale using these two imaging findings showed significant potential for predicting OS. These findings suggest that the presence of three or more 18F-FDG-avid bone lesions and extramedullary disease may be useful prognostic parameters for identifying high-risk patients.

18F-FDG-avid focal lesions and the presence of extramedullary disease on PET/CT scan are significantly associated with inferior OS in MM patients. The scale developed according to these predictors represents a potential prognostic tool for evaluation of patients with MM.