Circulating tumor cells: A promising marker of predicting tumor response in rectal cancer patients receiving neoadjuvant chemo-radiation therapy.

Wenjie Sun,Zhen Zhang,Ji Zhu,Weiqi Shen,Juefeng Wan,Guichao Li

doi:10.18632/oncotarget.10875

Abstract

PurposeThe aim of this study was to investigate the role of circulating tumor cells (CTCs) in assessing and predicting tumor response to neoadjuvant chemoradiotherapy (CRT) for patients with locally advanced rectal cancer (LARC).MethodsA total of 115 patients with T3-4 and/or N+ rectal cancer were enrolled. All patients received neoadjuvant CRT followed by radical surgery after 6-8 weeks. The pathological results after surgery were evaluated according to tumor regression grade (TRG) classification.ResultsBased on TRG score, patients were classified as responders (TRG3-4) and non-responders (TRG0-2). The baseline CTC counts of responders were significantly higher than those of non-responders (44.50±11.94 vs. 37.67±15.45, P=0.012). By contrast, the post-CRT CTC counts of responders were significantly lower than those of non-responders (3.61±2.90 vs. 12.08±7.40, P<0.001). According to ROC analysis, Δ%CTC (percentage difference in CTC counts between baseline and post-CRT) was identified as the stronger predictor to discriminate responders from non-responders (AUC: 0.860). The results of multivariate analysis also indicated that post-CRT CTC counts and Δ%CTC were significantly and independently associated with tumor response to CRT.ConclusionsThe detection of CTCs is a powerful and promising tool for evaluating and predicting responses to neoadjuvant CRT in LARC patients.

Highlights

Nowadays neoadjuvant chemoradiation therapy (CRT) combined with radical surgery has become the standard strategy in patients with locally advanced rectal cancer (LARC) [1,2,3,4,5]
A wide range of treatment responses has been shown after neoadjuvant CRT: some cases obtain complete disappearing of tumor after CRT but others have no response to therapy [6,7]
By use of receiver operating characteristic (ROC) analysis, we found that Circulating tumor cells (CTCs) was a good marker to distinguish cancer patients from healthy people

Summary

Introduction

Nowadays neoadjuvant chemoradiation therapy (CRT) combined with radical surgery has become the standard strategy in patients with locally advanced rectal cancer (LARC) [1,2,3,4,5]. A wide range of treatment responses has been shown after neoadjuvant CRT: some cases obtain complete disappearing of tumor after CRT but others have no response to therapy [6,7]. It’s very essential to predict accurately the responses to neoadjuvant CRT in order to carry out individualized therapy. Detecting and analyzing these tumor cells is very helpful for investigating the intrinsic characteristics of tumors and performing individualized treatment. Many techniques with different theories have been performed to detect CTCs [13,14,15,16,17]. Immunomagnetic bead separation based on antibodies for tumor cell surface antigens(e.g. CellSearch system) is one of the most prevalent methods employed to detect CTCs in the clinical settings. The CellSearch system, approved by US www.impactjournals.com/oncotarget

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