Staging monoclonal plasma cell disease: comparison of the Durie-Salmon and the Durie-Salmon PLUS staging systems.

PURPOSE: To investigate the concordance of the Durie-Salmon staging system with the Durie-Salmon PLUS staging system in monoclonal plasma cell disease.

MATERIALS AND

METHODS

Institutional review board approval was obtained, with waiver of informed consent. Lesions in 403 untreated patients (age range, 21-83 years) with monoclonal gammopathy of undetermined significance (MGUS) (n = 84), solitary plasmacytoma (n = 17), amyloid light-chain amyloidosis (n = 12), and multiple myeloma (MM) (n = 290) were first staged on the basis of the classic Durie-Salmon staging system, which included conventional radiography. After examination with whole-body (WB) magnetic resonance (MR) imaging, lesions in these patients were, in addition, staged by using the Durie-Salmon PLUS staging system. Bone marrow infiltration pattern and focal lesions described as intramedullary, transcortical, and soft-tissue lesions, were assessed. The staging levels of both systems were compared.

RESULTS

Of 84 patients with MGUS, lesions in 33 (39%) would have been staged differently with Durie-Salmon PLUS staging system when compared with Durie-Salmon staging system (stage I MM [37%], stage II MM [0%], and stage III MM [2%]). All 17 patients with plasmacytoma showed additional focal lesions or a diffuse infiltration leading to a classification as stage I MM (76%), stage II MM (12%), or stage III MM (12%) with Durie-Salmon PLUS. Of the 149 patients with stage I MM, lesions in 81 (54%) would have been staged differently with the Durie-Salmon PLUS staging system. Of the 21 patients with stage II MM, lesions in 19 (91%) would have been staged differently with Durie-Salmon PLUS staging system when compared with the Durie-Salmon staging system. Of the 120 patients with stage III MM, lesions in 72 (60%) would have been staged differently with the Durie-Salmon PLUS staging system.

CONCLUSION

Given the fact that the Durie-Salmon and Durie-Salmon PLUS staging systems were concordant in only 45% of all examined patients with monoclonal plasma cell disease, in most cases, treatment decisions depend on the staging system used and, thus, remain a matter of debate.