Prognostic value of primary tumor surgery in minor salivary-gland carcinoma patients with distant metastases at diagnosis: first evidence from a SEER-based study

Purpose: The prognostic value of primary tumor surgery (PTS) in minor salivary-gland carcinoma (MiSGC) with distant metastasis (DM) at diagnosis has never been investigated. In this study, we aimed to provide the first evidence. Patients and methods: The Surveillance, Epidemiology, and End Results (SEER) database was employed to identify MiSGC patients with DM at diagnosis. The prognostic value of PTS was evaluated by Kaplan-Meier methods, log-rank analyses, and multivariate Cox proportional-hazard regression models. Results: Of the 152 eligible patients included in our study, 50 (32.9%) had undergone PTS. Kaplan-Meier analyses showed that the PTS group had >20% increase in 1- and 2-year overall survival (OS) and cancer-specific survival (CSS) compared with their counterparts without PTS (PTS group vs no-PTS group, 1-year OS 66.1% vs 43.9%, 1-year CSS 69.9% vs 44.9%, 2-year OS 56.6% vs 24.2%, 2-year CSS 59.9% vs 25.7%). Compared with the no-PTS group, multivariate analyses also demonstrated a significantly decreased risk of overall mortality (HR 0.601, 95% CI 0.379-0.952; P=0.031) and cancer-specific mortality (HR 0.547, 95% CI 0.336-0.891; P=0.015) in the PTS group. Subgroup multivariate analyses revealed patients with T1-T3 oropharynx, nasal cavity, or paranasal sinus primary MiSGC, especially adenoid cystic carcinoma, might benefit from PTS (all P<0.05). Conclusion: PTS is associated with improved survival in highly selected MiSGC patients and may be considered in future clinical practice. However, prospective studies with larger sample size are still necessary to validate our findings.