Incidence of sinusitis and its influential factors in nasopharyngeal carcinoma patients after intensity-modulated radiotherapy

Objective: To investigate the incidence of sinusitis in nasopharyngeal carcinoma (NPC) patients before and after intensity-modulated radiotherapy (IMRT) and analyze the influential factors for incidence of sinusitis after IMRT. Methods: A retrospective analysis was performed on 283 NPC patients who received IMRT in our hospital from March 2009 to May 2011. CT or MRI scans were performed before and after IMRT to evaluate the incidence of sinusitis. The influential factors for incidence of sinusitis were analyzed by log-rank univariate analysis and logistic multivariate analysis. Results: The incidence rates of sinusitis in patients with T₁, T₂, T₃, and T₄ NPC before radiotherapy were 22.6%, 37.5%, 46.8%, and 61.3%, respectively (P =0.002). Among the 155 NPC patients without sinusitis before radiotherapy, the incidence rates of sinusitis at the end of radiotherapy and 1, 3, 6, 9, 12, and 18 months after radiotherapy were 32.9%, 43.2%, 61.3%, 68.4%, 73.5%, 69.1%, and 61.3%, respectively (P = 0.000). The univariate analysis showed that T stage, invasion into the nasal cavity, rhinopharynx flush, and radiation dose to the nasopharynx were associated with the incidence of sinusitis in NPC patients after IMRT (P = 0.003, 0.006, 0.002, and 0.020). The multivariate analysis showed that T stage, invasion into the nasal cavity, and rhinopharynx flush were the influential factors for incidence of sinusitis in NPC patients after IMRT (P = 0.002, 0.002, and 0.000). Conclusions: There is a higher incidence of sinusitis with higher T stage among NPC patients before radiotherapy. The incidence of sinusitis grows rapidly within 3 months after IMRT, reaches the peak level at 9 months, and tends to be stable at one year. T stage, invasion into the nasal cavity, and rhinopharynx flush are the influential factors for incidence of sinusitis in NPC patients after IMRT. (authors)