Intensity-modulated radiation therapy versus 2D-RT or 3D-CRT for the treatment of nasopharyngeal carcinoma: A systematic review and meta-analysis

To compare clinical treatment outcomes and late toxicities of intensity-modulated radiation therapy (IMRT) with those obtained with two-dimensional radiation therapy (2D-RT) or three-dimensional conformal radiation therapy (3D-CRT) in nasopharyngeal carcinoma (NPC). We searched all the eligible studies from the Cochrane Library, PubMed, Medline, and Embase. The meta-analysis was performed to compare odds ratio (OR) for overall survival (OS), tumor local control (LC), and late toxicities. A total of eight studies met the criteria to perform a meta-analysis including 3570 participants, with 1541 patients in the IMRT group and 2029 in the 2D-RT or 3D-CRT group. The IMRT group was associated with a better 5-year overall survival (OR = 1.51; 95% confidence interval (CI) 1.23–1.87; p = 0.0001), and tumor local control (LC) (OR = 1.94; 95% CI 1.53–2.46; p < 0.00001). According to CTCAE v3.0 (Common Terminology Criteria for Adverse Events) and RTOG/EORTC (Radiation Therapy Oncology Group/European Organisation for Research and Treatment of Cancer), the incidence of late xerostomia in those who received IMRT was significantly lower than that of the control group (OR = 0.18; 95% CI, 0.07–0.46; p = 0.0004). In addition, the radiation-induced chronic toxicities rate of trismus and temporal lobe neuropathy (TLN) were also significantly lower in the IMRT group than in the control group (OR = 0.18; 95% CI 0.04–0.83; p = 0.03; OR = 0.44; 95% CI 0.28–0.69; p = 0.0003, respectively). This systematic review and meta-analysis demonstrated that IMRT may obtain a better antitumor effect, and significantly decrease the incidence of radiation-induced late toxicities in patients with NPC.