Published OnlineFirst November 3, 2009; DOI: 10.1158/1078-0432.CCR-09-1095 Published Online First on November 3, 2009 as 10.1158/1078-0432.CCR-09-1095 Imaging, Diagnosis, Prognosis Circulating Tumor Cell as a Diagnostic Marker in Primary Lung Cancer Fumihiro Tanaka,1 Kazue Yoneda,1 Nobuyuki Kondo,1 Masaki Hashimoto,1 Teruhisa Takuwa,1 Seiji Matsumoto,1 Yoshitomo Okumura,1 Shakibur Rahman,1 Noriaki Tsubota,2 Tohru Tsujimura,3 Kozo Kuribayashi,4 Kazuya Fukuoka,4 Takashi Nakano,4 and Seiki Hasegawa1 Abstract Purpose: To investigate the diagnostic performance of circulating tumor cells (CTC) in discrimination between primary lung cancer and nonmalignant diseases as well as in prediction of distant metastasis. Patients and Methods: We prospectively evaluated CTCs in 7.5-mL samples of periph- eral blood sampled from patients with a suspicion or a diagnosis of primary lung can- cer. A semiautomated system was used to capture CTCs with an antibody against epithelial cell adhesion molecule. Results: Of 150 eligible patients, 25 were finally diagnosed as having nonmalignant dis- ease, and 125 were diagnosed as having primary lung cancer with (n = 31) or without (n = 94) distant metastasis. CTCs were detected in 30.6% of lung cancer patients and in 12.0% of nonmalignant patients. CTC count was significantly higher in lung cancer pa- tients than in nonmalignant patients, but a receiver operating characteristic (ROC) curve analysis showed an insufficient capability of the CTC test in discrimination be- tween lung cancer and nonmalignant diseases with an area under ROC curve of 0.598 (95% confidence interval, 0.488-0.708; P = 0.122). Among lung cancer patients, CTC count significantly increased along with tumor progression, especially with devel- opment of distant metastasis. The area under ROC curve for CTC count in prediction of distant metastasis was 0.783(95% confidence interval, 0.679-0.886; P < 0.001). When patients with one or more CTCs were judged as having metastatic disease, sensitivity and specificity of the CTC test were 71.0% and 83.0%, respectively. Conclusions: CTC is a useful surrogate marker of distant metastasis in primary lung cancer. (Clin Cancer Res 2009;15(22):6980–6) Primary lung cancer is the leading cause of cancer death in scanning (1). More importantly, even in patients without clin- most industrialized countries, and its high mortality is mainly ically detectable distant metastasis at the time of initial diagno- caused by frequent occurrence of distant metastasis. In fact, sis, distant metastasis may frequently develop during treatment ∼40% of lung cancer patients have distant metastasis detectable or long-time follow-up. Thus, in most lung cancer patients, tu- with current diagnostic modalities such as whole-body comput- mor cells may circulate in the blood with or without apparent ed tomography (CT) and positron emission tomography (PET) distant metastasis, and detection of such circulating tumor cells (CTC) may contribute to improvement in diagnosis and thera- py of lung cancer patients (2). Authors' Affiliations: Departments of 1Thoracic Surgery, 2Pathology, and However, in spite of many efforts for development of a sen- 3Thoracic Oncology, and 4Division of Respiratory Medicine, Department sitive detection system of CTCs, clinical significance of CTCs of Internal Medicine, Hyogo College of Medicine, Hyogo, Japan had not been established mainly due to lack of reproducibility Received 5/7/09; revised 6/17/09; accepted 6/18/09; published OnlineFirst and accuracy in detection of CTCs (2, 3). The CellSearch Sys- 11/3/09. Grant support: Grants-in-Aid 20390374 (F. Tanaka) for Scientific Research tem (Veridex LLC), a semiautomated system for quantitative (B) from the Japan Society for the Promotion of Science, Japan. evaluation of CTCs, has been recently developed, in which The costs of publication of this article were defrayed in part by the payment CTCs are immunomagnetically captured with an antibody of page charges. This article must therefore be hereby marked advertisement against epithelial cell adhesion molecule (EpCAM; ref. 3). in accordance with 18 U.S.C. Section 1734 solely to indicate this fact. The most important advantage of the CellSearch system is re- Note: Part of this study was presented at the 44th Annual Meeting of the American Society of Clinical Oncology, May 30 to June 3, 2008, Chicago, IL producibility across different laboratories, which is validated and at the 45th Annual Meeting of the American Society of Clinical Oncol- by a prospective multicenter study in metastatic breast cancer ogy, May 29 to June 2, 2009, Orlando, FL. (4). Based on accumulating data supporting the accuracy and Requests for reprints: Fumihiro Tanaka, Department of Thoracic Surgery, Hyogo precision in evaluating CTCs (5–8), the CTC test has been ap- College of Medicine, Mukogawa 1-1, Nishinomiya-city, Hyogo 663-8501, Japan. Phone: 81-798-45-6885; Fax: 81-798-45-6897; E-mail: [email protected]. proved in the United States of America by the Food and Drug F 2009 American Association for Cancer Research. Administration for monitoring of blood from metastatic doi:10.1158/1078-0432.CCR-09-1095 breast and colon cancer patients. In addition, several clinical Clin Cancer Res 2009;15(22) November 15, 20096980 www.aacrjournals.org Downloaded from clincancerres.aacrjournals.org on September 24, 2021. © 2009 American Association for Cancer Research. Published OnlineFirst November 3, 2009; DOI: 10.1158/1078-0432.CCR-09-1095 Circulating Tumor Cell in Primary Lung Cancer Patients and Methods Translational Relevance Study design. Patients who presented with a pathologic diagnosis The present study has revealed that circulating tu- of primary lung cancer or with a suspicion of primary lung cancer on mor cells (CTC) can be found and quantitatively eval- chest radiograph and/or CT at the Department of Thoracic Surgery, uated with a semiautomated system (CellSearch) in Hyogo College of Medicine hospital and agreed to the purpose of the patients with primary lung cancer, and that CTC study were eligible. Patients who have apparent or symptomatic count is useful diagnostic marker to predict develop- distant metastasis before enrollment were excluded from the study. In ment of distant metastasis. When the clinical value addition, patients who had concurrent or prior malignancy treated of the CTC test in diagnosis of distant metastasis is within in the previous 5 y were excluded. All patients provided written established in future clinical studies, CTC count will informed consent before enrollment. A 7.5-mL sample of peripheral blood was collected from each become a practical clinical marker, which can be patient, and was served for the CTC test. A complete clinical data noninvasively and repeatedly performed, not only including history, physical examination, and laboratory and radio- in determining clinical stage but also in monitoring graphic studies were also collected. In some primary lung cancer of therapeutic efficacy and predicting prognosis. In patients who underwent thoracotomy, pulmonary venous blood was addition, the present study has revealed that CTCs also sampled during thoracotomy, and was served for the CTC test are detected even in ∼20% of lung cancer patients for another study (12). without clinically detectable distant metastasis, For all patients enrolled, serum levels of carcinoembryonic antigen which suggests that CTC count is a surrogate marker (CEA) were measured using a commercially available electrochemilu- of micrometastasis. Thus, the CTC test may be po- minescence immunoassay system (Roche Diagnostics K.K.) following tentially marker in decision making of adjuvant che- a manufacturer's instruction; the manufacturer-suggested cutoff point of CEA to discriminate between nonmalignant disease and malignant motherapy following complete resection, which tumor was 5 ng/mL (13, 14). For patients with a suspicion of primary should be examined in future studies. lung cancer, bronchoscopic and/or trans-thoracic needle biopsy was ap- plied to obtain pathologic diagnosis; if failed, video-assisted thoraco- scopic biopsy was done. For lung cancer patients, whole-body CT, studies have revealed that the CTC test is a potentially useful brain CT or magnetic resonance imaging (MRI), and PET scanning were clinical marker in other malignant tumors such as prostate routinely conducted to evaluate tumor progression. Clinical stage (c- cancer (9–11). In lung cancer, however, little has been re- stage) was determined according to the current tumor-node-metastasis ported about the incidence of CTCs (3), and its clinical signif- classification as revised in 1997; for patents undergoing surgery for lung cancer, pathologic stage (p-stage) was also determined. This study icance remains unknown. Thus, we now conducted a was approved by the Institutional Review Board of Hyogo College of prospective study to examine the presence and incidence of Medicine. CTCs in primary lung cancer patients for evaluating its diag- Evaluation of CTCs (the CTC test). CTCs were isolated from nostic performance in discrimination between primary lung peripheral blood using the CellSearch system (Veridex LLC), and cancer and nonmalignant diseases as well as in prediction of the number of CTCs was determined following a manufacturer's distant metastasis. protocol (3). In brief, epithelial cells, which were captured using Fig. 1. Flowchart of diagnosis of patients enrolled in the study. www.aacrjournals.org 6981 Clin Cancer Res 2009;15(22) November 15, 2009