Published online Dec 24, 2020. doi: 10.5306/wjco.v11.i12.1029
Peer-review started: September 21, 2020
First decision: October 21, 2020
Revised: November 5, 2020
Accepted: November 28, 2020
Article in press: November 28, 2020
Published online: December 24, 2020
Mucoepidermoid carcinoma (MEC) is a rare malignancy of the head and neck; however, it accounts for a majority of the tumors of the salivary glands. This study used a national population-based registry to describe the pre-treatment and treatment-related prognostic factors that influence survival in patients with MEC of the major salivary glands. To our knowledge, this is the largest population-based study examining predictors of both overall and cause-specific survival of MEC of the major salivary glands.
To identify prognostic factors influencing overall survival (OS) and cause-specific survival (CSS) of patients with MEC of the major salivary glands.
We used the Surveillance, Epidemiology and End-Results Database of the National Cancer Institute to investigate a variety of factors that could influence survival of patients diagnosed with mucoepidermoid carcinoma of the major salivary glands. A total of 2210 patients diagnosed with MEC of the major salivary glands during the years of 1975-2016 were studied. The primary endpoints were OS and CSS. Cox regression analysis was used to perform univariate and multivariate analyses of clinical variables such as age at diagnosis, diagnosis year, sex, race, tumor size, stage, grade, treatment with or without surgical excision, and adjuvant radiotherapy treatment.
A total of 2210 patients diagnosed with MEC of the major salivary glands met inclusion criteria. In this study, 95% of patients underwent surgical excision and 41% received adjuvant radiation therapy. Median OS time for Grade I, II, and III/IV was 401 mo (± 48.25, 95%CI), 340 mo (± 33.68, 95%CI) and 55 mo (± 11.05, 95%CI), respectively. Univariate analysis revealed that lack of surgical excision was associated with decreased OS [hazard ratio (HR) 4.26, P < 0.0001] and that patients with localized disease had improved OS compared to both regional and distant disease (HR 3.07 and 6.96, respectively, P < 0.0001). Additionally, univariate analysis demonstrated that male sex, age over 50 at diagnosis, Grade III tumors, and increasing tumor size were associated with worsened OS (P < 0.0006). Univariate analysis of CSS similarly revealed that lack of surgical excision and Grade III carcinoma conferred decreased CSS (HR 4.37 and 5.44, respectively, P < 0.0001). Multivariate analysis confirmed that increasing age, in 10-year age bands, advanced tumor stage, increasing tumor size, Grade III carcinoma, male sex, and lack of surgical excision were associated with a statistically significant decrease in OS and CSS (P < 0.04). Of note, multivariate analysis revealed that the use of adjuvant radiation therapy was not associated with improved OS or CSS.
Multivariate analysis demonstrated increasing age, advanced tumor stage, increasing tumor size, Grade III carcinoma, male sex, and lack of surgical excision were associated with decreased OS and CSS (P < 0.04).
Core Tip: Mucoepidermoid carcinoma (MEC) of the major salivary glands is a rare cancer with a limited number of studies with high statistical power. The purpose of this study was to identify prognostic factors effecting overall survival (OS) and cause-specific survival (CSS) of individuals diagnosed with MEC of the major salivary glands. By using de-identified information from the Surveillance, Epidemiology and End-Results Program, we concluded that younger age at diagnosis, female sex, smaller tumor size, lower tumor grade, localized tumor growth, and more recent year of diagnosis were positive predictors of statistically significant improvements in OS and CSS.