Influence of 5-hydroxytryptamine and platelet count in peripheral blood on the prognosis of patients with hepatocellular carcinoma

Objective To investigate the association of platelet and its endogenous 5-hydroxytryptamine( 5-HT) with the prognosis of patients with hepatocellular carcinoma( HCC). Methods A retrospective analysis was performed for the clinical data of 210 patients with HCC who were treated in The First Affiliated Hospital of Xi'an Jiaotong University from January 2004 to December 2012,and according to platelet count,the patients were divided into low platelet group and high platelet group. Related factors and prognosis were compared between two groups. Peripheral blood samples were collected from 20 patients with recurrent/metastatic liver cancer and 32 patients with non-recurrent/metastatic liver cancer; ELISA was used to measure the serum level of 5-HT,and the platelet aggregation instrument was used to measure platelet aggregation rate. The chi-square test was used to investigate the association between platelet count and the clinicopathological characteristics of liver cancer,and the Mann-Whitney U test was used to compare platelet count,platelet aggregation rate,and 5-HT level in peripheral blood between groups. A univariate linear regression analysis was used to investigate the association between platelet count and survival time,as well as the association of 5-HT level with platelet count and platelet aggregation rate. The Kaplan-Meier method was used to analyze survival rate and recurrence rate,the log-rank test was used for comparison between groups,and a Cox regression analysis was used to investigate the influencing factors for the prognosis of HCC patients. Results There were significant differences between the patients with different platelet counts in age( χ2= 32. 304,P = 0. 044),tumor size( χ2= 35. 201,P = 0. 001),number of tumors( χ2=31. 304,P = 0. 032),Child class( χ2= 31. 250,P = 0. 036),and TNM stage( χ2= 35. 201,P = 0. 001). The multivariate Cox regression analysis showed that age,alpha-fetoprotein( AFP) level on admission,platelet count on admission,and treatment modality were independent risk factors associated with overall survival( all P < 0. 05),while age,AFP level on admission,tumor size,platelet count on admission,and treatment modality were risk factors associated with recurrence-free survival( all P < 0. 05). The survival analysis showed that compared with the low platelet group,the high platelet group had a significantly lower overall survival rate( χ2= 34. 060,P < 0. 001) and a significantly higher recurrence rate( χ2= 31. 030,P < 0. 001). With the increase in platelet count,overall survival and recurrence-free survival tended to decrease( R2 OS= 0. 034,POS= 0. 007; R2 DFS= 0. 045,PDFS= 0. 002). Compared with the non-recurrent/metastatic liver cancer group,the recurrent/metastatic liver cancer group had significantly higher platelet count( U = 2. 950,P = 0. 041),platelet aggregation rate( U = 2. 363,P = 0. 043),and serum free 5-HT level( U = 3. 082,P = 0. 048). The correlation analysis showed that serum 5-HT level was positively correlated with platelet count and maximum platelet aggregation rate in peripheral blood( both P < 0. 05). Conclusion Platelet count is an independent risk factor for overall survival and recurrence/metastasis in patients with HCC. Peripheral 5-HT level is positively correlated with platelet count and platelet aggregation rate and may be one of the potential indices for predicting the prognosis of HCC patients.