Characteristics, incidence, and risk factors for death from fatal pneumonia among patients with primary malignant bone tumors: a SEER-based observational study

BACKGROUND: (I) To determine whether patients with malignant bone tumors had a higher risk of dying from pneumonia compared with the general US population; (II) to identify the independent risk factor associated with fatal pneumonia among these patients. METHODS: We identified 18,583 patients diagnosed with primary malignant bone tumors between 1973 and 2016 from the Surveillance, Epidemiology, and End Results (SEER) database. Standardized mortality ratios (SMRs) were calculated based on the mortality data of the general population gathered by the National Center for Health Statistics, which provided the risk of death from pneumonia among cancer patients relative to that of the general population. Given that other causes of death were considered as competing events, we also designed the Fine-Gray model to identify demographic and tumor-related characteristics associated with a higher risk of dying from pneumonia among these patients. RESULTS: Patients with primary malignant bone tumors had a higher risk of dying from pneumonia than the general population after adjusting the distribution difference of age, sex, and race among them (SMR =2.79; 95% CI: 2.17–3.59). The older age, Black and earlier period of diagnosis were found to be the independent prognostic factor for a higher risk of death from pneumonia for these patients. Additionally, amputation due to malignant bone tumors significantly increased the risk of death from pneumonia compared with non-surgery. The highest mortality rate of pneumonia was observed among patients with chordoma. Interaction tests demonstrated that amputation only increased the relative risk of fatal pneumonia among patients with osteosarcoma. Throughout the follow-up period, the mortality rate of fatal pneumonia was the highest within the first year after diagnosis, and the highest relative suicide risks persisted over time in patients with osteosarcoma. CONCLUSIONS: To mitigate the risk of fatal pneumonia among patients with bone tumors, we call for long-term clinical monitoring of the lung condition among these patients, especially for those after amputation for bone tumors.