Failure patterns and prognostic factors for cervical node-negative nasopharyngeal carcinoma in the intensity-modulated radiotherapy era

Background: To evaluate the failure patterns and prognostic factors in patients with cervical node-negative nasopharyngeal carcinoma (NPC) in the intensity-modulated radiotherapy (IMRT) era.

Methods: Patients with cervical node-negative NPC treated with IMRT at the Sun Yat-sen University Cancer Center between February 2001 and December 2008 were retrospectively reviewed. The failure patterns, prognostic factors, and efficacy of additional chemotherapy were assessed.

Results: The median follow-up time was 78 months for 298 patients. The 5-year local recurrence-free survival (LRFS), nodal recurrence-free survival (NRFS), distant metastasis-free survival (DMFS), failure-free survival (FFS), and overall survival (OS) were 95.2%, 99.3%, 94.8%, 89.8%, and 92.9%, respectively. The rate of treatment failure remained high in patients with T4 disease (35.4%, 17/48), including eight of local recurrence, two of nodal recurrence, and seven of distant metastasis. Multivariate analyses showed that the primary gross tumor volume (GTVp) was significantly associated with LRFS, DMFS, FFS, and OS. Subgroup analysis revealed that patients with GTVp ≤ 42.5 cc had better 5-year LRFS (98.7% vs 81.4%, P < .001), 5-year DMFS (97.8% vs 82.5%, P < .001), 5-year FFS (96.1% vs 65.4%, P < .001), and 5-year OS (96.6% vs 78.2%, P < .001) than patients with GTVp > 42.5 cc. However, additional chemotherapy showed no significant survival benefit in stratification analysis.

Conclusions: Cervical node-negative NPC has a good prognosis in the IMRT era, and the primary tumor volume is the most important prognostic factor. Further exploration is needed to determine the optimal treatment strategy for patients with a high tumor burden.