Incidence of pneumonia and risk factors among patients with head and neck cancer undergoing radiotherapy

BACKGROUND: This study investigated the incidence and patient- and treatment-related risk factors related to pneumonia acquired during radiotherapy (PNRT) in head and neck cancer (HNC) patients. METHODS: Using the universal insurance claims data, 15,894 total HNC patients between 1998 and 2007 were included in this analysis. PNRT was defined as the occurrence of pneumonia within 90 days of the commencement of radiotherapy. Information also included some demographic characteristics, treatment-related factors, and comorbidities. Appropriate statistical tests were performed to assess the difference between patients with and those without PNRT. A logistic regression was used to estimate the odds ratio (OR) of PNRT among the variables examined. RESULTS: In total, 772 patients (4.86%) were identified with PNRT as the case group, whereas 15,122 subjects of the same cancer without PNRT formed the control group. Of patients with PNRT, 632 (81.9%) were hospitalized with a mean length of stay of 25.9 days. Results from the multiple logistic regression showed that an older age and certain comorbidities were associated with an increased risk of PNRT. Patients with cancer of the tongue, buccal mucosa, oropharynx, and hypopharynx/larynx were at particularly higher risk (OR = 1.28, 1.28, 1.67, and 1.74, respectively). Compared to radiotherapy alone, concurrent chemoradiotherapy had no effect on the PNRT. Patients in the PNRT group had higher overall medical costs and length of stay. CONCLUSION: The incidence of PNRT in HNC patients receiving radiotherapy was approximately 5%. Notably, an older age, certain comorbidities, and certain specific tumor sites were associated with an increased risk.