Correlation Between Skull Base Invasion and Bone Metastases in Locally Advanced Nasopharyngeal Carcinoma Patients

Objective To investigate the relationship between the skull base invasion and bone metastases in locally advanced nasopharyngeal carcinoma(NPC) patients.

Methods From January 1st, 2008 to March 31st, 2010, 518 patients with locally advanced NPC(Ⅲ stage, ⅣA stage, ⅣB stage, UICC2002 edition) were involved in this trial. All patients without prior treatment were divided into two groups according to skull base invasion or not: 243 cases without the skull base invasion (Group A), and 275 cases with the skull base invasion (Group B). We compared the incidence rate and the time of bone metastases between two groups.

Results The bone metastasis rate was 11.8%(61/518) in all involved patients, including 16(6.6%) cases in Group A and 45(16.4%) cases in Group B (P < 0.05). In 61 cases of bone metastases, single bone metastasis rate of Group B was higher than that of Group A (73.3% vs. 43.8%, P < 0.05); the median time of first bone metastasis in Group A and B were 14.0 and 19.1 months respectively, without significant difference (P > 0.05). Univariate and multivariate analysis showed that the skull base invasion was a poor prognostic factor for the bone metastasis in locally advanced NPC patients.

Conclusion The bone metastasis and single bone metastasis rate are high in the locally advanced NPC patients with skull base invasion. The skull base invasion is a poor prognostic factor for the bone metastasis.