Effect of Prolonged Radiotherapy Treatment Time on Survival Outcomes after Intensity-Modulated Radiation Therapy in Nasopharyngeal Carcinoma

Abstract

PurposeTo estimate the influence of prolonged radiation treatment time (RTT) on survival outcomes in nasopharyngeal carcinoma after continuous intensity-modulated radiation therapy.Methods and MaterialsRetrospectively review 321 patients with NPC treated between October 2009 and December 2010 and all of them underwent simultaneous accelerated intensity-modulated radiation therapy. The fractionated dose was 2–2.47 Gy/F (median 2.27 Gy), and the total dose for nasopharyngeal region was 64–74 Gy/ 28–33 fractions. The association of prolonged RTT and treatment interruption with PFS, LRFS and DFFS were assessed by univariate analysis and multivariate analysis. Survival analyses were carried out using Kaplan–Meier methodology and the log-rank test was used to assess the difference. The Cox regression proportional hazard model was used for multivariate analyses and evaluating the prognostic parameters for PFS, LRFS and DFFS.ResultsUnivariate analysis revealed no significant associations between prolonged RTT and PFS, LRFS, DFFS when dichotomized using various cut-off values (all P>0.05). In multivariate analysis, RTT (range, 36–63 days) as a continuous variable, had no influence on any survival outcome as well (P>0.05). T and N classification were independent prognostic factors for PFS, LRFS and DFFS (all P<0.05, except T classification for LRFS, P = 0.057). Age was an independent prognostic factor for PFS (hazard ratio [HR], 1.033; P = 0.008) and DFFS (HR, 1.032; P = 0.043).ConclusionWe conclude that no such association between survival outcomes and radiation treatment duration (range: 36–63 days) can be found in the present retrospective study, however, we have to remind that prolongation in treatment should be limited in clinical application and interruptions caused by any reason should be minimized as much as possible.

Effect of interrupted time during intensity modulated radiation therapy on survival outcomes in patients with nasopharyngeal cancer

“…Although the benefit of neoadjuvant chemotherapy or adjuvant chemotherapy is still open to debate, neoadjuvant chemotherapy or adjuvant chemotherapy is commonly prescribed for most patients with III-IV stage disease at our hospital. But it is worth noting that concurrent chemotherapy had no significant impact on PFS, LRFS or DFFS in our study and the previous study [10]. This may be caused by the fact that the subgroup receiving concurrent chemotherapy contained a significantly higher proportion of patients with locally advanced NPC.…”

Survival impact of treatment‐related time intervals in nasopharyngeal carcinoma in the United States

“…Currently, there is a lack of consensus concerning what is considered as prolonged RT or interrupted RT, and the methods to quantify this are heterogeneous. For example, some authors have examined total RT duration, whereas others have examined the number of continuous days that RT was interrupted . Furthermore, the existing published data largely consists of retrospective data that is small in sample size .…”

“…For example, some authors have examined total RT duration, whereas others have examined the number of continuous days that RT was interrupted . Furthermore, the existing published data largely consists of retrospective data that is small in sample size . To our knowledge, there is only one published data in a large prospective cohort investigating this question, which is by Yao et al In this study of 447 patients, Yao et al found that RT interruption was significantly associated with locoregional failure survival (LRFS) in the multivariable analysis (HR = 9.64, 95% CI, 4.10–22.65), but RT interruption was not significantly associated with OS in the multivariable model.…”

“…Recent studies have investigated whether several treatment‐related time intervals (TRTIs), such as time to radiation (TTR) and radiation duration (RTd), would impact survival in NPC patients. The results have been equivocal, with some studies finding a correlation between treatment interruptions/TTR with survival and others finding no correlation …”

The regulation and interaction of colon cancer‐associated transcript‐1 and miR7‐5p contribute to the inhibition of SP1 expression by solamargine in human nasopharyngeal carcinoma cells

“…The genetic susceptibility, environmental factors, exposure to chemical carcinogens, and Epstein-Barr virus (EBV) infection are considered the major reasons for this cancer type (Hildesheim & Wang, 2012). Radiotherapy alone or concurrent chemoradiotherapy are the main treatments for NPC patients and the survival rate has improved significantly especially in patients with locally and regionally advanced NPC (Baujat et al, 2006;Lee, Ma, Ng & Chan, 2015;Li et al, 2015). However, radiotherapy for NPC is notoriously difficult due to the invasive characteristics of the tumor, early local and distant metastasis; concomitant chemoradiotherapy-related toxicities (Du, Ying, Kong, Zhai & Hu, 2015;Jiang et al, 2015).…”