Clinical characteristics and prognosis of patients with hypopharyngeal cancers with multiple primary cancers: A propensity score matched analysis.

PURPOSE: This study aimed to identify the clinical characteristics of hypopharyngeal squamous cell carcinoma (HPSCC) patients with multiple primary cancers (MPCs) and to compare differences between patients with metachronous and synchronous MPCs. MATERIAL AND METHODS: This study included 219 patients with HPSCC treated at our center between 2008 and 2020; the clinical characteristics and prognosis of 66 patients with MPCs were analyzed. Propensity score matching (PSM) was used to balance the factors between patients with synchronous and metachronous MPCs. RESULTS: Sixty-six patients with HPSCC (66/219, 30.1%) experienced MPCs, of which 29 were synchronous and 37 were metachronous. The esophagus (n = 39, 59.1%), lung (n = 10, 15.2%), and oropharynx (n = 4, 6.1%) were the three most common sites of MPCs in both the synchronous and metachronous groups. More patients with synchronous MPCs were stage T1-2 (82.8% vs. 59.5%, P = 0.041) compared to those with metachronous MPCs. Among the 24 pairs of patients after PSM, patients with metachronous MPCs had higher 3-year progression-free survival (PFS) (52.5% vs. 16.3%, P < 0.001) and overall survival (OS) (58.5% vs. 22.1%, P = 0.001) than those with synchronous cancers. Multivariate Cox analysis showed that patients with synchronous MPCs had shorter PFS (HR 4.45, 95% CI 1.819-10.885, P = 0.001) and OS (HR 3.918, 95% CI 1.591-9.645, P = 0.003). CONCLUSION: MPCs are common among patients with HPSCC, and patients with metachronous MPCs had better survival than those with synchronous MPCs. Clinicians should be aware of the possibility of MPCs in patients with HPSCC and optimize treatment to improve outcomes.