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BACKGROUND AND PURPOSE: Xerostomia, caused by radiation-induced parotid damage, is the most commonly reported radiotherapy (RT) complication for nasopharyngeal carcinoma (NPC). The purpose of this study was to evaluate the value of intravoxel incoherent motion (IVIM) MR in monitoring radiation-induced parotid gland damage and predicting the risk of xerostomia. METHODS: Fifty-four NPC patients were enrolled and underwent at least three IVIM MR scans: before (pre-RT), after 5 fractions of (5th-RT), halfway through (mid-RT), and after RT (post-RT). The degree of xerostomia patients was assessed before each MR examination. Furthermore, the time when patients first reported xerostomia symptoms was recorded. The changes in IVIM parameters throughout RT, as well as the relationships between IVIM parameters and xerostomia, were analysed. RESULT: All IVIM parameters increased significantly from pre-RT to post-RT (p < 0.001). The rates of D, D* and f increase increased significantly from pre-RT to mid-RT (p < 0.001), indicating that cell necrosis mainly occurs in the first half of RT. In multivariate analysis, N3 (p = 0.014), pre-D (p = 0.007) and pre-D* (p = 0.003) were independent factors influencing xerostomia. D and f were significantly higher at 5th-RT than at pre-RT (both p < 0.05). IVIM detected parotid gland injury at 5th-RT at an average scanning time of 6.18 ± 1.07 days, earlier than the 11.94 ± 2.61 days when the patient first complained of xerostomia according to the RTOG scale (p < 0.001). CONCLUSIONS: IVIM MR can dynamically monitor radiation-induced parotid gland damage and assess it earlier and more objectively than RTOG toxicity. Moreover, IVIM can screen people at risk of more severe xerostomia early.
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BACKGROUND: Genome-scale CRISPR-Cas9 knockout screening may provide new insights into the mechanism underlying clinical radioresistance in nasopharyngeal carcinoma (NPC), which is remain largely unknown. Our objective was to screen the functional genes associated with radiosensitivity and radioresistance in NPC, laying a foundation for further research on its functional mechanismand. METHODS: CRISPR-Cas9 library lentivirus screening in radiation-treated NPC cells was combined with second-generation sequence technology to identify functional genes, which were further validated in radioresistant NPC cells and patient tissues. RESULTS: Eleven radiosensitive and radioresistant genes were screened. Among these genes, the expression of FBLN5, FAM3C, MUS81, and DNAJC17 were significantly lower and TOMM20, CDKN2AIP, SNX22, and SP1 were higher in the radioresistant NPC cells (C666-1R, 5-8FR) (p < 0.05). CALD1 was highly expressed in C666-1R. Furthermore, we found knockout of FBLN5, FAM3C, MUS81 and DNAJC17 promoted the proliferation of NPC cells, while CDKN2AIP and SP1 had the opposed results (p < 0.05). This result was verified in NPC patient tissues. Meanwhile, KEGG analysis showed that the Fanconi anemia pathway and the TGF-ß signaling pathway possibly contributed to radiosensitivity or radioresistance in NPC. CONCLUSIONS: Nine genes involved in the radiosensitivity or radioresistance of NPC: four genes for radiosensitivity (FBLN5, FAM3C, MUS81, and DNAJC17), two genes for radioresistance (CDKN2AIP, SP1), two potential radioresistant genes (TOMM20, SNX22), and a potential radiosensitive gene (CALD1). Genome-scale CRISPR-Cas9 knockout screening for radiosensitive and radioresistant genes in NPC may provide new insights into the mechanisms underlying clinical radioresistance to improve the efficacy of radiotherapy for NPC.
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BACKGROUND: To retrospectively analyze the efficacy and safety of concurrent chemoradiotherapy (CCRT) plus recombinant human endostatin (Endostar, CCRT + E) versus CCRT alone in locally advanced nasopharyngeal carcinoma (LANPC). METHODS: A retrospective analysis of patients initially treated for LANPC from November 2016 to March 2019 was performed: trial group received CCRT + E and control group received CCRT. Prognoses and adverse effects were evaluated. RESULTS: Eighty-eight patients were included: 43 received CCRT + E and 45 received CCRT. The median follow-up time was 54.0 (range: 8.0-64.0) months. The survival data of the CCRT + E and CCRT groups were as follows: 3-year progression-free survival (PFS) rates, 81.4% and 63.6% (hazard ratio [HR] 0.418, 95%CI 0.181-0.963, P = 0.034); 3-year distant metastasis-free survival (DMFS) rates, 88.3% and 77.3% (HR 0.370, 95%CI 0.132-1.039, P = 0.049); 3-year overall survival rates, 88.2% and 81.9% (HR 0.437, 95%CI 0.151-1.260, P = 0.114); and 3-year locoregional failure-free survival rates, 87.8% and 86.9% (HR 0.795, 95%CI 0.242-2.616, P = 0.705). Three months after radiotherapy, the complete response (CR) rates of cervical lymph node regression were 97.7% and 82.2% for the CCRT + E and CCRT groups (P = 0.041). The corresponding CR rates were 100% and 80.0% for lymph node necrosis (P = 0.001) and 100% and 85.2% for extranodal extension (P = 0.041). The CCRT + E group had higher incidence of grade 3/4 leukopenia (32.6% vs. 13.3%, P = 0.031), with similar results for late toxicity. CONCLUSIONS: CCRT + E significantly prolonged 3-year PFS and DMFS in LANPC, and patients had better lymph node regression.