Risk and clinicopathological features of osteosarcoma metastasis to the lung: A population-based study

BACKGROUND: Osteosarcoma is the most common primary sarcoma of the bone. Lung osteosarcoma metastases at diagnosis have a significantly poor prognosis, even when surgery plus chemotherapy are performed. Our goal was to analyze clinical and sarcoma characteristics that could help identify factors related to an increased rate of lung metastasis and to identify different modes of treatment and its correlation with survival. MATERIALS AND METHODS: The Surveillance, Epidemiology, and End Results (SEER) database was used to identify all osteosarcoma patients diagnosed from 2010 to 2015. Patient characteristics such as age, sex, ethnicity, marital status, tumor location, histologic grade, surgery, chemotherapy, radiation therapy, SEER cause-specific death classification, survival, and lung metastasis were collected. These factors were analyzed using Univariate and multivariate regression models in survival analyses. RESULTS: A total of 1057 osteosarcoma patients diagnosed from 2010 to 2015 were included, of which 176 were patients with lung metastasis. Substantial disparities in the rate of lung metastasis existed when osteosarcoma patients were stratified according to tumor location (P = 0.0002) and tumor size (P < .001). Using a Multivariate Cox regression model, being older than 30 years (vs. younger than 30, HR = 2.171, 95% CI = 1.623–2.905, P < .0001), having a tumor >5–10 cm (vs. <5 cm, HR = 2.046, 95% CI = 1.153–3.632, P = 0.0014) and >10 cm (vs. <5 cm, HR = 3.610, 95% CI = 2.066–6.310, P < .0001) were related to an increased HR for all-cause death. The HR decreased in patients with surgery (vs. no surgery, HR = 0.189, 95% CI = 0.138–0.260, P < 0.0001) and osteosarcoma. As for osteosarcoma patients with lung metastases, Multivariate Cox regressions revealed that an increased HR was associated with being older than 30 years (vs. younger than 30 years, HR = 2.142, 95% CI = 1.273–3.605, P = .0041) and married (vs. no marriage, HR = 2.418, 95% CI = 1.400–4.176, P= .0015), while a decreased HR was related to having had surgery (vs. no surgery, HR = 0.282, 95% CI = 0.171–0.464, P < .0001) and chemotherapy (vs. no chemotherapy, HR = 0.107, 95% CI = 0.050–0.229, P < .0001). CONCLUSIONS: Advanced age (older than 30 years) and large tumors were related to a higher risk of lung metastases in osteosarcoma patients. Therefore, patients who were diagnosed at advanced age or had large tumors should receive comprehensive chest CT scans. Surgery and chemotherapy can significantly improve the survival of metastatic patients, while radiotherapy did not improve survival in these patients.