Higher peripheral blood CTPC levels were associated with greater BM tumor burden and more abnormal routine laboratory markers in patients with newly diagnosed MM, suggesting CTPC quantification may serve as an adjunctive marker for baseline disease assessment.
Key Findings
Results
CTPC-higher patients had significantly lower hemoglobin levels compared to CTPC-lower patients.
Median hemoglobin was 73.5 g/L in the CTPC-higher group versus 107.0 g/L in the CTPC-lower group.
Difference was statistically significant (P < .001).
This association remained significant after Benjamini-Hochberg false-discovery-rate correction (q ≤ 0.018).
CTPC levels were negatively correlated with hemoglobin levels (ρ = -0.68; P < .001).
The association remained significant in age- and sex-adjusted logistic regression analyses.
Results
CTPC-higher patients had significantly lower albumin levels compared to CTPC-lower patients.
Median albumin was 30.9 g/L in the CTPC-higher group versus 38.2 g/L in the CTPC-lower group.
Difference was statistically significant (P = .006).
This association remained significant after FDR correction (q ≤ 0.018).
Albumin remained associated with CTPC-higher status in age- and sex-adjusted analyses.
Results
CTPC-higher patients had significantly higher β2-microglobulin levels compared to CTPC-lower patients.
Median β2-microglobulin was 6.97 mg/L in the CTPC-higher group versus 3.25 mg/L in the CTPC-lower group.
Difference was statistically significant (P = .004).
This association remained significant after FDR correction (q ≤ 0.018).
β2-microglobulin remained associated with CTPC-higher status in age- and sex-adjusted analyses.
Results
CTPC-higher patients had significantly higher bone marrow plasma cell percentages on smear examination compared to CTPC-lower patients.
Median BM plasma cell percentage was 34.75% in the CTPC-higher group versus 12.00% in the CTPC-lower group.
Difference was statistically significant (P = .005).
This association remained significant after FDR correction (q ≤ 0.018).
BM plasma cell percentage on smear remained associated with CTPC-higher status in age- and sex-adjusted analyses.
Results
CTPC levels were positively correlated with bone marrow plasma cell percentage on smear examination.
This correlation remained significant after Benjamini-Hochberg FDR correction (q ≤ 0.018).
The finding supports CTPCs as a reflection of BM tumor burden.
Correlation was assessed across 41 patients with evaluable CTPC data.
Methods
The study used a 0.07% cutoff to stratify patients into CTPC-higher and CTPC-lower groups.
51 consecutive patients with newly diagnosed MM were included; 41 had evaluable CTPC data.
CTPC-higher group: n = 20; CTPC-lower group: n = 21.
CTPCs were quantified using ten-color multiparameter flow cytometry from peripheral blood.
This was a retrospective single-center study design.
Exploratory logistic regression was adjusted for age and sex.
Conclusions
The study explicitly notes that cross-sectional findings from this limited sample do not establish prognostic value for CTPCs.
The authors state: 'These cross-sectional findings from this limited sample do not establish prognostic value.'
The study was limited to baseline disease assessment correlations.
The authors describe CTPC quantification as potentially serving as 'an adjunctive marker for baseline disease assessment in regional clinical settings.'
The study was retrospective with a sample size of 51 patients (41 evaluable).
What This Means
This research suggests that the number of tumor plasma cells circulating in the blood (called CTPCs) reflects how advanced multiple myeloma is at the time of diagnosis. In a study of 51 newly diagnosed myeloma patients at a single center, patients with higher levels of CTPCs in their blood had more cancerous plasma cells in their bone marrow, lower hemoglobin (indicating more anemia), lower albumin (a protein that reflects nutritional and disease status), and higher β2-microglobulin (a marker associated with more advanced disease). These relationships held up even after statistical corrections for multiple comparisons and adjustments for patient age and sex.
The practical implication is that measuring CTPCs in peripheral blood using a ten-color flow cytometry test could serve as a less invasive way to get a snapshot of how much tumor burden a patient has at diagnosis, complementing traditional bone marrow biopsies. Because blood draws are simpler and less uncomfortable than bone marrow biopsies, CTPC measurement could be a useful additional tool in routine clinical assessment, particularly in settings where advanced diagnostics may be limited.
This research suggests that CTPCs track with standard disease markers in newly diagnosed myeloma, but the authors are careful to note that this small, single-center, cross-sectional study cannot determine whether CTPC levels predict long-term outcomes such as survival or treatment response. Larger prospective studies would be needed to determine whether CTPC levels have prognostic value beyond their association with disease burden at diagnosis.
Du X, Hu D, Fu W, Hu H, Chen W, Xu X, et al.. (2026). Circulating tumor plasma cells correlate with tumor burden and routine laboratory markers in newly diagnosed multiple myeloma: A retrospective single-center study.. Medicine. https://doi.org/10.1097/MD.0000000000051073