The clinical value of detecting circulating tumour cells in the peripheral blood of nasopharyngeal carcinoma patients

The aim of the present study as to analyse the associations between circulating tumour cells (CTCs) and the clinical parameters of nasopharyngeal carcinoma (NPC). Peripheral blood (7.5 ml) from 68 first-diagnosed NPC patients was collected to detect and identify CTCs by cluster of differentiation (CD)45 immunomagnetic separation. Immunofluorescent staining of cytokeratin-18, CD45 and DAPI, and fluorescence in situ hybridization were combined with the centromere of chromosome 8 (CEP8) probe method to analyse the associations between CTCs and clinical parameters. One-year follow-up of the NPC patients who received standardized treatment was also performed to analyse the associations between CTCs, tumour development and the treatment effect. The detection rate of CTCs in the 68 NPC patients was 98.5% and the positive rate of CTCs was 60.3%. The positive rates of CTCs in the I–III and IV stage patients were 51.1 and 78.3%, respectively; the rate was 90.0% in the M(1) stage and 55.2% in the M(0) stage. The differences were statistically significant (P<0.05). The mean CTC counts were 3.86±2.36 and 5.70±2.91 in the M(0) and M(1) stages, respectively, which was significantly different (P=0.031). The 12-month follow-up record suggested tumour progression for 17 patients, and the one-year progress free survival rate was 74.6%. Among the CTC-positive stages III–IV patients, the disease progression rate of the patients who had received treatment including chemotherapy/intensity-modulated radiation therapy (IMRT) was 83.3%, which was higher than that of the patients who received treatment including chemotherapy/IMRT/chemotherapy, and the difference was statistically significant (P<0.05). The results of the present study suggested that CTCs were closely associated with the stages of NPC. The later clinical stages may have higher CTC-positive rates for NPC. Treatment with chemotherapy/IMRT/chemotherapy may be more effective for CTC-positive patients in stages III–IV than the use of chemotherapy/IMRT.