Prognostic significance and optimal candidates of primary tumor resection in major salivary gland carcinoma patients with distant metastases at initial presentation: A population-based study.

OBJECTIVES: To investigate the prognostic significance and identify optimal candidates of primary tumor resection (PTR) for patients with metastatic major salivary gland carcinoma (MaSGC) at diagnosis.

MATERIALS AND METHODS: Patients with metastatic MaSGC were identified from the Surveillance, Epidemiology and End Results (SEER) database. Kaplan-Meier analyses, log-rank tests and multivariate Cox regression models were employed to evaluate the therapeutic roles of PTR in the overall cohort and different subgroups.

RESULTS: Overall, 255 patients were included in our study, among whom 80 (31.4%) received PTR. PTR was associated with decreased overall mortality (OM) and cancer-specific mortality (CSM) in the overall cohort (PTR vs No-PTR, HR: 0.363, 95%CI: 0.204-0.646, p = .001 for OM; HR: 0.439, 95%CI: 0.243-0.794, p = .006 for CSM). When we focused on site-specific metastases, receipt of PTR significantly reduced the risk of OM for patients with lung, bone or distant lymph node involvement (all p < .05), whereas this surgical procedure not only failed to bring survival benefit, but even seemed to insignificantly increase the mortality risk once liver metastases were presented (PTR vs No-PTR, HR: 1.109, 95%CI: 0.279-4.412 for OM; HR: 1.596, 95%CI: 0.364-7.004 for CSM). In addition, subgroup analyses showed that patients with stage T1-3 disease, younger age (<65), single-site metastases and high-risk pathologies might benefit from PTR.

CONCLUSION: Our study for the first time verifies the favorable prognostic impact of PTR for highly-selected patients with metastatic MaSGC at diagnosis and has the potential to be adopted in future clinical practice, although long-term prospective studies are warranted.