[The relationship between extend types and distant metastasis of nasopharyngeal carcinoma]

To explore the relationship between extend types and distant metastasis of nasopharyngeal carcinoma (NPC).

Retrospective analyze 260 patients with nasopharyngeal carcinoma, among which 162 cases were distant metastasis (metastasis group) and 98 cases were neither distant metastasis nor recurrence (disease-free group) over 5 years after radiotherapy. All these patients were staged depending on CT or MRI image before treatment and divided into local-regional type(T(1-2)N(0-1)) for 36 cases and upward invasion type (T(3-4)N(0-1)) for 68 cases and downward invasion type (T(1-2)N(2-3)) for 75 cases and mixed type (T(3-4)N(2-3)) for 81 cases. The differences between two groups was analyzed using Chi-square test.

The local-regional type and upward invasion type was 25.3% for the metastasis group and 64.3% for the disease-free group. The downward and mixed invasion was 74.7% for the metastasis group and 35.7% for the disease-free group. The rate(proportion) of N(2-3) was significantly higher in metastasis group than in disease-free group with limited extension (84.4% vs. 33.3%, P < 0.01). The rates(proportion) of N(0-1) and N(2-3) were also significantly higher in metastasis group than in disease-free group with severity extension (T(3-4) (60% vs. 36.1% and 68.4% vs. 40%, P < 0.01).

The extent of cervical lymph node metastases is one of the most important factors of NPC with distant metastasis, severity extension of primary disease should also be in consideration. Even the limitations of primary disease, once cervical lymph node metastasis occurs, the risk of distant metastasis is significantly increased.