IntroductionTo investigate the outcome of locoregionally advanced nasopharyngeal carcinoma (NPC) treated with intensity-modulated radiation therapy (IMRT) after induction chemotherapy, with or without concomitant chemotherapy.MethodsBetween August 2003 and March 2007, 370 patients with locoregionally advanced NPC were treated with IMRT. Presenting stages were stage IIB in 62, stage III in 197, and stage IVA/B in 111 patients. All patients except for 36 patients with cervical lymphadenopathy of 4 cm or less in diameter received 2 cycles of cisplatin-based neoadjuvant chemotherapy. Forty-eight patients received cisplatin-based concurrent chemotherapy as well.ResultsWith a median follow-up time of 31 months (range 5 to 61 months), the 3-year local control, regional control, metastasis-free survival (MFS), disease-free survival (DFS) and overall survival (OS) rates were 95%, 97%, 86%, 81% and 89%, respectively. Multivariate analyses revealed that both age (≤ 60 vs. >60) and N-classification are significant prognosticators for OS (P = 0.001, hazard ratio [HR] 2.395, 95% confidence interval [CI] 1.432-4.003; P = 0.012, hazard ratio [HR] 2.614, 95% confidence interval [CI] 1.235-5.533); And N-classification is the only significant predicative factor for MFS (P = 0.002, [HR] 1.99, 95% CI 1.279-3.098). T-classification and concurrent chemotherapy were not significant prognostic factors for local/regional control, MFS, DFS, or OS. Subgroup analysis revealed that concurrent chemotherapy provided no significant benefit to IMRT in locoregionally advanced NPC, but was responsible for higher rates of grade 3 or 4 acute toxicities (50% vs. 29.8%, P < 0.005). No grade 3 or 4 late toxicity including xerostomia was observed. However, two patients treated with IMRT and neoadjuvant but without concurrent and adjuvant chemotherapy died of treatment related complications.ConclusionIMRT following neoadjuvant chemotherapy produced a superb outcome in terms of local control, regional control, MFS, DFS, and OS rates in patients with stage IIB to IVB NPC. Effective treatment strategy is urgently needed for distant control in patients diagnosed with locoregionally advanced NPC.

High-dose RT is indicated for local disease control in patients with metastatic NPC, and may improve survival when actively used with systemic chemotherapy and local treatment for metastatic foci. Patients with single-organ metastases have a better prognosis as compared with those with more widespread metastases.

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Roller intervals are the key parameters of the stagger spinning process, which affect the shape accuracy and productivity of the products. In this article, the effects of different roller intervals in axial and radial directions on tool forces, wall thickness, and strain and stress variations in stagger spinning have been analyzed numerically by the finite element analysis. The results show that with the increasing of the axial roller intervals, the differences between tool force components (axial, radial, and tangential) become lower at first, and then have the trend to be higher. The similar phenomenon on tool force occurs when the radial interval of roller 3 increases and that of roller 2 decreases. Wall thickness variations are mainly affected by axial roller intervals; the bigger the axial intervals are, the higher the variations of wall thickness that would be seen. Meanwhile, the real reductions of wall thickness are mainly affected by radial roller intervals. When the radial interval of roller 3 is larger than that of roller 2, there would be a higher real wall thickness reduction.