Survival predictors of major salivary gland cancer

Abstract

Background Salivary gland cancer (SGC) represents about 3-5% of all head and neck cancers. Sadly, a rise of its annual incidence has been reported worldwide with a range of 0.5 to 2 per 100,000. In this study, we hypothesized new prognostic models for SGC including examined lymph nodes (LNs), negative (NLNs), positive (metastatic) LNs (PLNs) counts, and LN ratio (LNR=PLNs/ELNs×100).

Methods The patient data of this retrospective population-based study were retrieved from the Surveillance, Epidemiology, and End Results (SEER) database. The X-tile program was used to determine the best threshold of ELNs, NLNs, PLNs counts, and LNR depending on the appropriate threshold with the minimum P-value and maximum Chi2 test. Moreover, we used Kaplan-Meier analyses to create our survival curves.

Results Data for 6,175 patients with major SGC had been analyzed. From X-tile analysis, we found that patients having >21 ELNs, compared with patients having ≤6 ELNs, >3 PLNs and >40% LNR were associated with a worse survival. We also found a mean survival time of 82.36 months with overall survival and major SGC-specific survival of 54.83/70.12%, respectively.

Conclusions In the current study, we have demonstrated the prognostic value of ELNs, PLNs, NLNs, and LNR. We highly suggest adding the ELNs and PLNs counts and/or LNR into the current staging system. We also encourage conducting further studies in order to shed light on mechanisms underlying the association between the ELNs and PLNs counts, LNR and major SGC survival.