Downloaded from http://journals.lww.com/nuclearmedicinecomm by BhDMf5ePHKbH4TTImqenVNPUfnk57qBdcG27v2203J42Rxq2XIsoZFfmd+FerENmI58hu+YYEw0= on 10/04/2020 Performance of FDG PET/CT in postoperative colorectal cancer patients with a suspected recurrence and a normal CEA level Jai Hyuen Lee a , Seok Gun Park a , Keum Nahn Jee b , Dong Guk Park c , Hwan Namgung c and Il Han Song d Purpose The performance of 2-deoxy-2-[ 18 F]fluoro- D-glucose positron emission tomography/computed tomography (FDG PET/CT) has been not established for the evaluation of recurrent colorectal cancer. The aim of this study was to evaluate the diagnostic value of FDG PET/CT in postoperative colorectal cancer patients with normal carcinoembryonic antigen (CEA) levels. Methods This retrospective study was conducted on 63 FDG PET/CT cases, involving postoperative colorectal cancer patients suspected of having recurrent or metastatic lesions with normal CEA levels. The diagnostic performance of FDG PET/CT was evaluated based on diverse suspected conditions, using physical examination, a conventional imaging work-up, and endoscopy. Histopathology, a clinical imaging work-up (including an FDG PET/CT examination), and determination of tumor marker levels during the follow-up served as the reference standard. Results The sensitivity, specificity, and accuracy for FDG PET/CT were 95, 76.6, and 88.8% for a lesion-by-lesion analysis, and 96.3, 86.1, and 90.5% for a case-by-case analysis, respectively. Three false-negative lesions among 107 suspected recurrent findings were identified as compared with nine false-positive lesions. For radiologically suspected recurrent or metastatic conditions, FDG PET/CT diagnostic performance was superior to radiological image modalities, for both lesion-by-lesion and case-by-case analyses. On follow-up of patients with normal CEA levels, but high CA19-9 levels, the use of FDG PET/CT detected true-positive findings in 63.3% of cases. Conclusion FDG PET/CT is a valuable tool to distinguish recurrence or metachronous tumor from postoperative changes or other benign lesions in postoperative colorectal cancer patients with normal CEA levels and radiologically or clinically suspicious lesions. Nucl Med Commun 31:576–582  c 2010 Wolters Kluwer Health | Lippincott Williams & Wilkins. Nuclear Medicine Communications 2010, 31:576–582 Keywords: CEA, colorectal cancer, recurrence, PET/CT Departments of a Nuclear Medicine, b Radiology, c General Surgery and d Gastroenterology, Dankook University College of Medicine, Cheonan, Korea Correspondence to Dr Jai Hyuen Lee, MD, Department of Nuclear Medicine, Dankook University Medical College, Dongnam-ku, Anseo-dong, Cheonan, 330-715, Korea Tel: + 82 41 550 3297; fax: + 82 41 550 6955; e-mail: jaihyuenlee@dankook.ac.kr Received 8 December 2009 Revised 27 January 2010 Accepted 3 February 2010 Introduction Colorectal cancer (CRC) is the second most common cause of cancer in both men and women in South Korea [1]. Despite effective surgical management, combined with neoadjuvant or adjuvant chemoradiotherapy, the recurrence rate is 40–50% [2,3]. It has been observed that many recurrent CRC patients frequently have a chance of being cured with a sophisticated diagnosis, followed by adequate therapy. Early detection of the recurrent disease, metastases or metachronous CRC have an influence on the patient’s survival and quality of life. For postoperative surveillance, most clinicians use a regular physical examination, determination of levels of tumor markers [including carcinoembryonic antigen (CEA) and cancer antigen (CA) 19-9] [4], endoscopy, and a conventional imaging work-up [including computed tomo- graphy (CT) or magnetic resonance imaging] [5]. Recently, 2-deoxy-2-[ 18 F]fluoro-D-glucose (FDG) positron emission tomography (PET) or PET/CT has been widely used to detect the recurrences or metastases in postoperative CRC patients. On account of the low sensitivity or false positivity of the use of tumor markers to detect early recurrences after surgery or additional radiation therapy, conventional follow-up strategies have some limitations in detecting the recurrences [6–8]. Several published studies have shown that FDG PET or FDG PET/CT are superior to conventional imaging modalities in patients with recur- rent CRC or metastases, but tumor marker levels for these patients have not been documented [9–11]. FDG PET or FDG PET/CT has enormous potential for the evaluation of recurrences or metastases in CRC patients with elevated CEA levels, during follow-up. In 2007, Sarikaya et al. [12] reported that FDG PET showed a high-positive predictive value for the detection of liver metastases in postoperative colorectal patients with normal CEA levels. However, this study had several Original article 0143-3636  c 2010 Wolters Kluwer Health | Lippincott Williams & Wilkins DOI: 10.1097/MNM.0b013e32833845b7 Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.