Some studies have suggested that circulating plasma cells (CPCs) might have prognostic value in multiple myeloma (MM), but the findings remain controversial, say researchers from Zhengzhou University in the People’s Republic of China. However, the development of highly sensitive and specific diagnostic methods, such as polymerase chain reaction (PCR) and flow cytometry (FCM), the researchers say, make it possible to explore whether CPCs can serve as a biomarker in MM. To that end, they conducted the first meta-analysis to provide better insight into the prognostic value of CPCs in MM.
The researchers examined findings from 11 studies involving 2,943 patients in 5 countries. Peripheral blood samples were analyzed using FCM, PCR, slide-based immunofluorescence assay (IF), and conventional morphology (CM).
Circulating plasma cell status reflected aggressive disease more than tumor burden, the researchers say. Patients in the CPC-positive groups had more aggressive disease and a worse overall survival (OS) rate compared with patients in the CPC-negative groups. The presence of CPCs was “strikingly” associated with elevated the International Staging System score but not the Durie-Salm staging system (DS) score. This difference may be associated, the researchers suggest, with the fact that the DS stage predominantly reflects tumor burden, which is significantly reduced now by newer therapies.
In subgroup analyses, the patients in the FCM and CM groups had worse prognosis for both disease progression and OS. The PCR subgroup showed prognostic significance for disease progression but not OS, and the IF subgroup for OS but not disease progression.
One question the researchers were also interested in answering was whether it mattered when the sample was taken. However, pooled hazard ratios for OS and disease progression were “fairly stable,” they say, and not influenced by sampling time. Regardless of whether CPCs are detected in an early stage or in relapse patients, the researchers add, CPC status may serve as a useful tool to guide treatment and prognosis.
Source:
Li J, Wang N, Tesfaluul N, Gao X, Liu S, Yue B. PLoS One. 2017;12(7):e0181447.
doi: 10.1371/journal.pone.0181447.
