Prognostic factors in mucoepidermoid carcinoma of the minor salivary glands: A single-center retrospective study

Critical Appraisal of Histologic Grading for Mucoepidermoid Carcinoma of Salivary Gland: Is an Objective Prognostic 2-tiered Grading System Possible?

Multiple 3-tiered grading systems exist for mucoepidermoid carcinoma (MEC), leading to controversial results on the frequency and prognostic values of each grade. We aimed to identify prognostic histologic factors and to evaluate grading schemes in this retrospective study of 262 resected primary head and neck MECs. The rate of nodal metastasis was 8.4%. Large tumor size, tumor fibrosis, infiltrative border, lymphovascular invasion, perineural invasion, atypical mitosis, mitotic index (MI) ≥4/2 mm 2 (4/10 HPFs), necrosis, and pT4 stage were associated with increased risk of nodal metastasis. The 5-year recurrence-free survival (RFS) was 95%. Significant prognostic factors for RFS included infiltrative border, tumor-associated lymphoid stroma, architectural patterns (macrocystic, microcystic, and noncystic), anaplasia, atypical mitosis, MI, necrosis, lymphovascular invasion, margin, pT stage, and tumor size. Nuclear anaplasia, high mitotic rate, and ≥25% microcystic component were significant independent prognostic factors on multivariate survival analysis. There was no significant difference between low-grade (LG) and intermediate-grade (IG) MECs in terms of risk of nodal metastasis and outcomes using all 4 known grading systems. Rather, high-grade MEC was consistently associated with an increased risk of nodal metastasis at presentation and decreased RFS and distant metastasis-free survival (DMFS) compared with the LG/IG MECs. We therefore recommend simplifying MEC grading to a 2-tiered grading scheme using MI and/or tumor necrosis. Using a 2-tiered grading, high-grade histology independently predict RFS, and is associated with a 25% risk of nodal metastasis, a 5-year RFS of 76%, and a 5-year DMFS of 76%, whereas LG MEC has a nodal metastasis rate of 7.0%, 5-year RFS of 97% and 5-year DMFS of 99%.

Molecular Targets in Salivary Gland Cancers: A Comprehensive Genomic Analysis of 118 Mucoepidermoid Carcinoma Tumors

INTRODUCTION

Salivary gland carcinomas (SGC) are histologically diverse cancers and next-generation sequencing (NGS) to identify key molecular targets is an important aspect in the management of advanced cases.

METHODS

DNA was extracted from paraffin embedded tissues of advanced SGC and comprehensive genomic profiling (CGP) was carried out to evaluate for base substitutions, short insertions, deletions, copy number changes, gene fusions and rearrangements. Tumor mutation burden (TMB) was calculated on approximately 1.25 Mb. Some 324 genes in the FoundationOne CDX panel were analyzed.

RESULTS

Mucoepidermoid carcinoma (MECa) mutations were assessed. CDKN2A and CDKN2B GA were common in mucoepidermoid carcinoma (MECa) (52.5 and 30.5%). PIK3CA was also common in MECa (16.9%). ERBB2 amplification/short variants (amp/SV) were found in MECa (5.9/0%). HRAS GA was common in MECa (14.4%) as well. Other targets, including BAP1, PTEN, and KRAS, were noted but had a low incidence. In terms of immunotherapy (IO)-predictive markers, TMB > 10 was more common in MECa (16.9%). PDL1 high was also seen in MECa (4.20%).

CONCLUSION

SGC are rare tumors with no FDA-approved treatment options. This large dataset reveals many opportunities for IO and targeted therapy contributing to the continuously increased precision in the selection of treatment for these patients.

Prognostic analysis and nomogram establishment in patients with mucoepidermoid carcinoma of the tongue: a population-based study using the SEER database

OBJECTIVES

To describe the clinicopathological characteristics and determinants of survival of patients with mucoepidermoid carcinoma (MEC) of the tongue.

METHOD

Retrospective population-based study was conducted using the data of patients diagnosed with MEC of the tongue from the Surveillance, Epidemiology, and End Results (SEER) database between 2004 and 2016.

RESULTS

A total of 200 cases of MEC of the tongue were identified. The cohort was composed of 56.5% females. The mean age at diagnosis was 58.8 years. The base of the tongue was the most common primary site (72.5%). Most cases (80.9%) presented with T1 and T2. Lymph node metastases was present in 40.9% of cases, while distant metastases only observed in 2.2% of cases. Overall survival (OS) at 2, 5, and 10 years was 80.2%, 69.8%, and 52.4%, respectively. 77.5 percent of cases (155/200) underwent surgery, and 66 cases received both surgery and radiation therapy. Patients with post-operative radiation had much longer disease-specific survival (DSS). Advanced T stage, distant metastasis contributed independently to shorter OS, while the use of surgery is an independently favorable prognostic factor for OS. In addition, an OS-specific nomogram was established, and the C-index for OS prediction was 0.74 (95% CI 0.67-0.81).

CONCLUSION

This rare malignancy is associated with a generally favorable prognosis, and T stage, distant metastasis as well as surgical therapy are independent predictors of OS.