Immune cell changes following chemotherapy in advanced pancreatic cancer with variations based on gender.

To explore the changes in blood inflammatory cells (neutrophils, monocytes, platelets) and adaptive immune cells (lymphocytes) during chemotherapy, we retrospectively analysed medical records from 66 patients with unresectable Pancreatic Ductal Adenocarcinoma (PDAC) treated with the Gemcitabine-nab-Paclitaxel (GnP) regimen. Evaluations were conducted at baseline (pre-GnP, TA), after the first cycle (TB), and after the third cycle (TC) of treatment. In metastatic PDAC (mPDAC), the monocyte-to-lymphocyte ratio significantly increased at both TB and TC compared to TA, whereas no such change was observed in locally advanced PDAC (laPDAC) (interaction: p = 0.006). Platelet levels rose over time in both phenotypes, with a more pronounced increase in mPDAC (intergroup: p = 0.008). When stratified by gender, males with mPDAC showed an increase in monocyte percentages among total white blood cells (intergroup: p = 0.018), while both phenotypes exhibited rising platelet-to-lymphocyte ratios over time. In females, the platelet-to-lymphocyte ratio increased more significantly in laPDAC than in mPDAC (interaction: p = 0.046). GnP treatment notably increased circulating inflammatory cells and their relationships with lymphocytes in a manner dependent on both disease phenotype and gender. Pretreatment factors such as monocyte counts < 0.6 × 10/µl, lymphocyte counts > 1 × 10/µl, and a monocyte-to-lymphocyte ratio < 0.43 were identified as independent predictors of survival.