The Longitudinal Change of Circulating Tumor Cell During Chemotherapy and Its Correlation with Disease Features, Treatment Response and Survival Profile of Advanced Gallbladder Carcinoma

The current study aimed to investigate the relation of circulating tumor cell (CTC) with clinicopathological features. In addition, its longitudinal change during chemotherapy and its correlation with prognosis in advanced gallbladder carcinoma (GBC) patients were explored. Totally 45 unresectable, locally advanced or metastatic GBC patients who underwent chemotherapy were enrolled in this prospective study. The CTC in 7.5 ml blood was detected at pre-treatment and 3 months post-treatment. CTC was almost detectable in all advanced GBC patients before treatment, whose count was positively correlated with metastatic disease (vs. local advanced disease) (P=0.002), number of organs with metastases (P=0.006), and CA199 level (P=0.002). After treatment, CTC count declined from 4.0 (range: 0.0-83.0) at pre-treatment to 2.0 (range: 0.0-36.0) at post-treatment (P=0.003). Interestingly, pre-treatment CTC count (P=0.270) was of no difference, while post-treatment CTC count was lower (P=0.038) in objective-response patients compared to that in non-objective-response patients; meanwhile, both pre-treatment CTC count (P=0.017) and post-treatment CTC count (P<0.001) were lower in disease-control patients compared with those in non-disease-control patients. Importantly, pre-treatment CTC count ≥2 (versus <2) was only correlated with worse progression-free survival (PFS) (P=0.014) but not overall survival (OS) (P=0.057); while pre-treatment CTC count ≥5 (versus <5), post-treatment CTC count ≥2 (versus <2), post-treatment CTC count ≥5 (versus <5), CTC count up (versus equal/down) were all correlated with poor PFS and OS (all P<0.050). In conclusion, higher CTC count during chemotherapy correlates with worse treatment response, PFS and OS in advanced GBC patients, which implies that CTC measurement may optimize the prognostication and individualized treatment in these patients.