Platelet count, GM-CSF, IL-15 predict metastasis in pancreatic ductal adenocarcinoma

Low platelet counts, along with low levels of interleukin (IL)-15 and granulocyte-macrophage colony-stimulating factor (GM-CSF), seem to be good prognostic indicators of metastatic disease in patients with pancreatic ductal adenocarcinoma (PDAC), a recent study has found.

The study included 72 PDAC patients (mean age 60.3 years, 56.9 percent men) from whom blood samples were collected. Commercially available human multiplex screening assays were used to measure the levels of 38 cytokines and angiogenic factors, including platelet count, GM-CSF, IL-15, total bilirubin, and C-reactive protein, among others. The outcome of interest was metastasis.

At baseline, 55.6 percent of participants had locally advanced or advanced cancer, with PDAC stages 3 or 4. In terms of classical risk factors, 12.5 percent of participants were obese while 51.5 percent were smokers. Body mass index differed significantly across TNM stages (p=0.05), while smoking did not (p=0.32).

Biomarkers also correlated with disease prognosis. For instance, significantly lower counts of platelets, though still within the normal range, was associated with advanced-stage PDAC, and in those with vs without metastasis. A similar effect was reported for C-reactive protein, IL-15, CM-CSF, and the vascular endothelial growth factor receptor 2.

Multivariate logistic regression analysis showed that platelet count, IL-15, and GM-CSF were significant and negative predictors of metastasis in PDAC. Setting specific cut-off values for each marker led to stronger risk estimates. The combination of platelet count ≤290×10⁹/L and IL-15 ≤2.4 pg/mL yielded an odds ratio (OR) of 10.0 (95 percent confidence interval [CI], 1.99–54.5; p<0.001), while the inclusion of GM-CSF ≤50 pg/mL improved the OR to 21.0 (95 percent CI, 3.14–221.0; p<0.0001).