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. 2018 Aug 22;13(8):e0199014. doi: 10.1371/journal.pone.0199014

Fig 1. Study population selection.

Fig 1

Patients with squamous cell carcinoma of head and neck cancer (HNSCC) were selected from the Registry for Catastrophic Illness Patient (RCIP) database in the National Health Insurance Research Database (NHIRD) in Taiwan.