Suggestions for surveillance and radiation strategy in nasopharyngeal carcinoma treated with IMRT: Based on hazard-rate and patterns of recurrence.

OBJECTIVE: The study was designed to appraise the locoregional recurrence patterns using conventional two-dimensional radiotherapy (2D-RT) and intensity modulated radiation therapy (IMRT) in nasopharyngeal carcinoma (NPC) in order to better establish the scenario of the modern radiotherapy and the duration of surveillance.

MATERIALS AND METHODS: We reviewed the institutional database to identify patients with pathologically confirmed, non-metastatic NPC who completed radical 2D-RT or IMRT at our center from 2000 to 2011. We collected data on clinicopathologic features, treatments and outcomes. Statistical analyses were performed using SPSS 20.0 or STATASE 14.0.

RESULTS: The median follow-up was 60.1 months. Of 2315 patients, 1289 (53%) were treated with 2D-RT and 1026 (47%) with IMRT. IMRT group achieved better locoregional control rate, with the 5-year locoregional relapse-free survival (LRRFS) were 84.9% and 87.7% among patients received 2D-RT and IMRT, respectively (P = 0.050). IMRT was superior to 2D technique in terms of local relapse-free survival (LRFS) (88.4% vs 91.1%, P = 0.047) and the advantage was only significant in T3-4 subgroup (81.6% vs 90.2%, P = 0.000). Similar neck control rates were observed using different RT techniques. And the recurrence time appeared to be postponed by IMRT, with peaks accounting for the year 1.5 and year 3-4 compared to which was predominant at the first two years using 2D-RT in nature.

CONCLUSIONS: IMRT provided an improved LRRFS in overall stage and LRFS in advanced T stage for NPC compared with 2D-RT. Annual hazard of recurrence also changed with RT techniques.