Study On The Application Of Circulating Tumor Cells In The Post-operative Follow-Up Of Early Breast Cancer Patients

Background:Circulating tumor cells(CTCs)that detach from the primary tumor and circulate in the peripheral blood have the potential to form distant metastases.It has been well-documented that the presence of CTCs in early breast cancer is associated with future development of recurrent metastasis 4.Accumulated studies have established the critical role for CTCs in predicting unfavorable survival rates for metastatic breast cancer(MBC)patients 5-8,12.Consistent with these findings,a previous multi-center clinical trial in China(CBCSG004,China Breast Cancer Clinical Study Group)by our group not only confirmed that the presence of>5 CTCs before and after a new line of systemic therapy was significantly associated with shorter progression-free survival(PFS)(hazard ratio(HR)= 1.93;95%confidence interval(Cl)= 1.39-2.69;P<0.001)and overall survival(OS)(HR = 3.76;95%CI=2.35-6.01;P<0.001)but also found that the prognostic value of CTCs varied in different disease subtypes of MBC in Chinese patients12.In keeping with these findings,the prognostic value of CTCs in patients with non-MBC,as assessed at the time of primary diagnosis,has been shown convincingly in a recent large pooled analysis involving 3,173 patients8.This analysis additionally demonstrated that the presence of CTCs was positively associated with a larger tumor size,intensified lymph node involvement and unfavorable histological grade.The SUCCESS trial(EUDRA-CT No.2005-000490-21)first reported the time-related prognostic associations of CTCs in non-MBC patients.The prevalence of CTCs was evaluated after two follow-up periods;CTCs were detected in 18.6%and 8.5%of patients at 2 and 5 years,respectively13.At the 2017 San Antonio Breast Cancer Symposium(SABCS),Sparano et al.presented evidence that the presence of CTCs in peripheral blood,even 5 years after primary diagnosis,was associated with an 18.3-fold increased risk of late recurrence in hormone receptor(HR)-positive breast cancer patients11.This finding underlines the clinical validity of CTC as a prognostic biomarker for late recurrence in HR-positive breast cancer.More importantly,the rate of positive CTC results was 4.8%at five years after diagnosis,and the presence of CTC was not associated with any specific patient characteristics in this study.This finding raised the possibility of tumor dormancy in relapse-free patients-detectable CTCs decreased gradually,and the correlations between CTCs and pathological characteristics weakened over time.Although the prognostic value of CTCs in breast cancer has been well-established,the risk factors associated with the presence of CTCs has not been well-evaluated,especially in long-term follow-up.Diseases related to metabolic dysfunction,such as obesity and hyperglycemia,have recently been considered"emergent hallmarks" of cancer,representing the novel notion that tumor cells could reprogram metabolism to adapt to the active neoplastic proliferative state14.Remarkably,meta-analyses including large numbers of patients have provided evidence that obesity increased the risk of recurrence and mortality rates by approximately 35%-40%15.Herein,to further confirm the predictive value of CTC in patients with early-stage HR positive breast cancer and explore the relevant factors of CTC during the postoperative follow-up,our study is mainly divided into the following two parts.Chapter 1 Clinical application of CTC in early stage HR-positive breast cancer patientsObjective:To investigate the correlation between CTCs and clinicopathological features and analyze the prognostic value of CTC in patients with early ER positive breast cancer.Methods:A total of 221 patients with non-metastatic breast cancer(T1-3N0-3M0)were recruited in Guangdong Provincial People's Hospital from 2009 to 2015.The prevalence and number of CTCs were assessed using the CellSearch System at a mean time of 20.6±16.5 months after surgery.Collect clinical data of all enrolled patients.The correlations between CTCs and the clinicopathological features were analyzed by chi-square test,and Kaplan-Meier survival curve was used to analyze the prognostic value of CTC in early ER positive breast cancer patients.Results:Among the 221 patients,CTCs were detected in 25 patients and the positive rate was 11.3%.We performed a univariate analysis on the basic clinical features of all enrolled patients.The results showed that the positive rate of CTCs in patients with invasive ductal carcinoma was lower than other pathological types(P = 0.003).The presence of CTC was not related to the patient's age,tumor size,histological grade,and HER2 status.Although the patients in this study is still being followed up,the survival data currently available is limited.We still performed a preliminary Kaplan-Meier survival analysis of the collected survival data.The results showed that the disease-free survival(DFS)and overall survival(OS)were significantly better in the CTC-negative group than in the CTC-positive group(P=0.013,P=0.001).Conclusions:In early ER-positive breast cancer patients,the positive rate of CTC was 11.3%,and the presence of CTCs was related to the pathological type.In addition,DFS and OS were significantly better in CTC-negative breast cancer patients than in CTC-positive patients(P=0.013,P=0.001).Chapter 2 The potential related factors of circulating tumor cells in post-operative patients with early stage breast cancerObjective:Although circulating tumor cells(CTCs)have been well-established as promising prognostic biomarkers in both early breast cancer and metastatic settings,little is known regarding the prognostic relevance of CTCs in the long-term postoperative monitoring of patients with non-metastatic breast cancer(non-MBC).Herein,we investigated the associations of CTCs with clinicopathological features and metabolic-related variables such as obesity and hyperglycemia.Methods:We recruited 264 patients with postoperative stage ?-? breast cancer at Guangdong General Hospital from Jan 2009 to Dec 2015.Additionally,this study also screened patients with complete baseline and follow-up metabolic level-related test data.Finally,67 patients treated with Aromatase inhibitors(AIs)and 23 patients without endocrine therapy were enrolled.The prevalence and number of CTCs were assessed using the CellSearch System at a mean time of 21.6 months after surgery(ranged from 0-81 months).The CTC assay results were correlated with the clinicopathological features,metabolic-related variables.A multivariate logistic regression analysis was performed to further determine the independent predictors of CTCs.Results:CTCs were detected in 10.6%of all patients.The positive rate of CTCs in patients with infiltrating ductal carcinoma was lower than that in patients with other pathological types(9%vs.23.3%P=0.020).More importantly,the presence of CTCs was positively correlated with the blood glucose level(p=0.015)and high-density lipoprotein level(p=0.030).No association was observed between CTCs and clinicopathological features,except that the pathological type(OR:1.795,95%CI:1.046-3.081;p=0.034)was an independent predictor of CTCs according to the multivariate logistic regression analysis.Moreover,the multivariate logistic regression analysis showed that the blood glucose level(OR:1.190 95%Cl:1.010-1.402;p=0.037)was also an independent predictor of the presence of CTCs.We also found that Apolipoprotein B100,low-density lipoprotein,was significantly increased in patients treated with letrozole(p = 0.004,p = 0.016)during follow-up.In the anastrozole group,Apolipoprotein A1 had a low baseline level.After a median follow-up of 20 months,Apolipoprotein A1 was significantly elevated in both patients treated with anastrozole and letrozole(p = 0.044,p = 0.034).Aromatase inhibitor therapy does not affect triglycerides,HDL levels.And we did not observe any correlation between CTC and endocrine therapy.Conclusions:This study revealed potential associations between CTCs and metabolic-related factors in Chinese patients with non-MBC and supports a hypothesis that metabolic dysfunction in breast cancer patients might influence the biological activityof metastatic breast cancer,leading to a higher prevalence of CTCs.