The Role of Circulating Tumor Cells in the Prognosis of Local Recurrence and Local Residual Nasopharyngeal Carcinoma Undergoing Endoscopic Resection

Abstract

Purpose. To investigate the role of circulating tumor cells in the prognosis of local recurrence and local residual nasopharyngeal carcinoma undergoing endoscopic surgery. Methods. A total of 56 patients with locally residual nasopharyngeal carcinoma (NPC) who underwent nasal endoscopic surgery from August 2018 to December 2021 were included. The status of circulating tumor cells (CTC) before and after surgery was detected, and its relationship with clinical characteristics and postoperative survival was analyzed. Results. After nasal endoscopy, the positive rates of CTC and mesenchymal CTC (MCTC) detected in patients with nasopharyngeal carcinoma were significantly lower than those before treatment ( $P=0.0376$ ; $P=0.0212$ ). Before nasal endoscopy, the status of CTC and MCTC was significantly correlated with the T stage ( $P<0.05$ ). After nasal endoscopy, the status of CTC and MCTC was significantly correlated with the TNM stage, T stage, and first radiotherapy mode ( $P<0.05$ ). The PFS of patients with different clinical characteristics was analyzed, and the results showed that the PFS of NPC patients with CTC (+) was significantly shorter than that of CTC (−) patients (18.71 vs. 22.47, $P<0.05$ ) and the PFS of NPC patients with MCTC (+) was significantly shorter than that of MCTC (−) patients (18.22 vs. 22.30, $P<0.05$ ). The PFS of NPC patients in TNM stage (I-II) was significantly longer than that in TNM stage (III) patients (22.53 vs. 18.57, $P<0.05$ ). The PFS of NPC patients whose first radiotherapy mode was conventional was significantly longer than that of patients whose first radiotherapy mode was enhanced (22.14 vs. 16.85, $P<0.05$ ). The COX analysis showed that MCTC and TNM stages were independent risk factors affecting the prognosis of local recurrence or local residual nasopharyngeal carcinoma after endoscopic resection ( $P<0.05$ ). Conclusion. The detection of CTC is helpful for the prognosis evaluation of local recurrence or local residual NPC after endoscopic resection of NPC. The MCTC is an important factor affecting the prognosis of NPC patients.