SEER study population
cancer, tumor, Cancer
TUMOR, METASTASIS, LUNG METASTASIS, CANCER, LUNG METASTASES, METASTASES, CANCER
The National Cancer Institute’s (NCI’s) SEER program collects the population-based cancer data in the US. In this part, all data were extracted from SEER 17 registries, November 2021 submission (2000–2019), representing approximately 26.5% of the US population. Because the details of site-specific metastasis, including bone, brain, liver, and lung metastases, are provided since year 2010, all data were extracted since then. The criteria used to identify eligible cases and the study design were presented in The following variables were extracted from the database, including year of diagnosis, age (1–9 years, 10–19 years, and 20–39 years), race (white, black, and others), gender (male and female), primary site (appendicular [C40.0-C40.9] and axial [C41.0-C41.9]), tumor grade (low-grade [I/II], high-grade [III/IV], and unknown), tumor size (<5cm, 5-10cm, ≥10cm, unknown), lymph node status (negative, positive, and unknown), and site-specific metastasis. Except for synchronous lung metastasis, all other three site-specific metastases at diagnosis were grouped into one variable, i.e., SSM, with a yes denoted one or more other three site-specific metastases. Treatment information included surgery, radiotherapy, and systemic treatment.