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Abstract Background The impact of radiotherapy interruption due to the Spring Festival holidays in China on the survival of patients with nasopharyngeal carcinoma (NPC) is unclear. Methods Nontrial patients with locoregionally advanced NPC receiving radiotherapy plus induction chemotherapy (IC) and/or concurrent chemotherapy (CC) were included (N = 5035) and divided into two groups based on the Spring Festival-induced radiotherapy interruption. Kaplan–Meier curves for overall survival (OS) and failure-free survival (FFS) were compared between rival groups. Impact of the timing of radiotherapy interruption (during or outside the Spring Festival) on survival was investigated in a propensity score-matched dataset. We adopted ordination correspondence analysis to determine the cut-off of radiotherapy prolongation for prognostic prediction, and accordingly performed subgroup analysis based on delayed days and chemotherapy details. Individual patient data of three phase III NPC trials (NCT00677118, NCT01245959, NCT01872962) were used for validation (N = 1465). Results Radiotherapy interruption was most frequently observed between December to January of the following year. Significantly lower OS and FFS were associated with the Spring Festival-induced interruption of radiotherapy (P = 0.009 and 0.033, respectively), but not that interruption of IC. In two matched comparison groups, the timing of radiotherapy interruption during the Spring Festival was more likely to lead to a decrease in FFS than outside the Spring Festival (P = 0.046), which was not observed in the validation using clinical trial data or in the subgroup analysis based on the 5-day delayed time. The absence of CC and the accumulated dose of cisplatin

Abstract Objectives Induction chemotherapy (IC) now is gaining recognition for the treatment of nasopharyngeal carcinoma (NPC). The current study was conducted to examine the association between prognosis and the interval between IC and radiotherapy (RT) in NPC patients. Methods Patients with newly diagnosed, non-metastatic NPC who were treated with IC followed by RT from 2009 to 2012 were identified from an inpatient database. Overall survival (OS), disease-free survival (DFS), distant metastasis-free survival (DMFS) and locoregional recurrence-free survival (LRFS) were compared between those with interval ≤ 30 and > 30 days by Kaplan-Meier and log-rank analyses; Cox modeling was used for multivariable analysis. Results A total of 668 patients met inclusion criteria with median follow-up of 64.4 months. Patients were categorized by interval: 608 patients with interval ≤ 30 days, and 60 with interval > 30 days. The 5-year OS, DFS, DMFS and LRFS rates were 86.6, 78.2, 88.0 and 89.8% for patients with interval ≤ 30 days, respectively, and 69.2, 64.5, 71.2 and 85.1% for patients with interval > 30 days, respectively. The prolonged interval was a risk factor for OS, DFS and DMFS with adjusted hazard ratios (95% confidence intervals) were 2.44 (1.48–4.01), 1.99 (1.27–3.11) and 2.62 (1.54–4.47), respectively. Conclusions Prolonged interval > 30 days was associated with a significantly higher risk of distant metastasis and death in NPC patients. Efforts should be made to avoid prolonged interval between IC and RT to minimize the risk of treatment failure.

Abstract Background To compare the efficacy of ipsilateral lower neck sparing irradiation (ILNSI) versus ipsilateral lower neck prophylactic irradiation (ILNPI) for unilateral or bilateral neck node-negative nasopharyngeal cancer (NPC). Methods A comprehensive literature search of PubMed, EMBASE, the Cochrane Library and other public databases was conducted in October, 2017. The outcomes were 3-year overall/regional recurrence-free/disease-free/distant metastasis-free survival (OS/RRFS/DFS/DMFS) and ipsilateral lower neck (ILN) recurrence. We performed subgroup analysis of ILNSI versus ILNPI for different radiotherapy techniques. Sensitivity analysis was performed to examine the stability of the results. Results Nine head-to-head comparative studies (2, 521 patients) were included in the meta-analysis. For the comparison of ILNSI versus ILNPI, there was no significant difference in 3-year OS (HR = 1.16, 95% confidence interval [CI] = 0.85–1.58, P = 0.36), RRFS (HR = 1.37, 95% CI = 0.76–2.47, P = 0.30), DFS (HR = 1.08, 95% CI = 0.80–1.44, P = 0.62) and DMFS (HR = 1.00, 95% CI = 0.69–1.44, P = 0.99). ILNSI and ILNPI also led to equivalent ILN recurrence rates (OR = 0.98, 95% CI = 0.47–2.03, P = 0.96). No significant heterogeneity was observed for any outcome. Subgroup analysis confirmed no significant differences between ILNSI and ILNPI for any outcome, regardless of radiotherapy technique. Sensitivity analysis indicated all outcomes were highly stable in favor of the original conclusions. Conclusions ILNSI provided equivalent survival outcomes and regional control compared to ILNPI; ILNSI represents an appropriate alternative strategy for patients with unilateral or bilateral neck node-negative NPC.

Background: This prospective study was conducted to evaluate inter- and intra-fraction errors in nasopharyngeal carcinoma (NPC) patients undergoing volumetric modulated arc therapy (VMAT) using cone-beam computed tomography (CBCT) and to thus obtain planning target volume (PTV) margins to effectively guide treatment in the future. Methods: Fifteen NPC patients scheduled to undergo VMAT were prospectively enrolled in the study. For each patient, three CBCT scans were obtained; one after daily conventional positioning, one after online correction with 2 mm tolerance and one after 1 week of VMAT delivery. The scans were registered to the planning CT to determine the inter- and intra-fraction errors. Patient positioning errors were analyzed for time trends over the course of radiotherapy. PTV margins were calculated from the systematic (∑) and random (σ) errors. Results: The average absolute values of the pre-correction, post-correction and intra-fraction errors (in order) were 1.1, 0.6 and 0.4 mm in the medial-lateral (ML) direction, 1.2, 0.7 and 0.5 mm in the superior-inferior (SI) direction and 1.1, 0.7 and 0.5 mm in the anterior-posterior (AP) direction. The corresponding ∑ were 1.0-1.4 mm, 0.4-0.5 mm and 0.2-0.4 mm, while the corresponding s were 0.7-0.8 mm, 0.6-0.7 mm and 0.5-0.6 mm. With time, gradual increases in both the inter- and intra-fraction three-dimensional displacements were observed (P = 0.019 and P = 0.044, respectively). The total PTV margins accounting for pre-correction and intra-fraction errors were 3.4-4.1 mm and those accounting for post-correction and intra-fraction errors were 1.7-2.2 mm. Conclusions: CBCT is an effective modality to evaluate and improve the accuracy of VMAT in NPC patients. Inter- and intra-fraction three-dimensional displacements increased as a function of time during the course of radiotherapy. In our institution, we recommend a PTV margin of 5 mm for NPC patients undergoing VMAT without CBCT and 3 mm for those treated with rigorous daily CBCT scans. [ABSTRACT FROM AUTHOR]