The prospective observational clinical study will recruit 50 metastatic nasopharyngeal carcinoma (mNPC) patients, detecting patient's chemosensitivity with the circulating tumor cells (CTCs) from peripheral blood and prdicting patient's treatment efficacy with CTCs dynamic change.
NPC patients with distant metastasis after 3 months of primary radiotherapy, and not suitable for local treatment
At least having one measurable metastatic lesion
All genders，range from 18～70 years old
ECOG score 0 ~ 1
Have or are suffering from other malignant tumors;
Participating in other clinical trials;
Drug or alcohol addition;
Do not have full capacity for civil acts;