INTRODUCTION: Primary malignancy of the middle ear is rare and consists of a variety of histologic subtypes. The purpose of this study was to investigate the clinical features and survival outcomes of patients with middle ear malignancies at a population level.

METHODS: Records of patients diagnosed with a middle ear malignancy from 1973 to 2016 were extracted using SEER*Stat from the Surveillance, Epidemiology, and End Results (SEER) database. SPSS was used to conduct 5-year survival analysis. Significance was determined using the Chi-square test, Log-rank (Mantel-Cox) test, and the Wilcoxon signed rank test.

RESULTS: A total of 431 patients met our database search criteria. Patients with squamous cell carcinoma (SCCA) were significantly older than those with adenocarcinoma (P<0.0001). Black patients comprised a greater proportion of the adenocarcinoma group (17.8%) than of the SCCA group (5.6%) (P=0.0009). Five year Disease Specific Survival (DSS) for SCCA, adenocarcinoma, other carcinoma, and non-carcinoma subtypes varied significantly at 54.6%, 82.1%, 71.8%, and 82.6%, respectively (P<0.0001). Non-carcinoma subtypes were more likely to present with local disease, as opposed to regional or distant disease, when compared to SCCA (P=0.0027). There was an improved 5-year survival for adenocarcinoma patients that had surgery versus those who did not (P=0.023). However, there was no significant difference in 5-year survival between surgical versus non-surgical groups for SCCA, other carcinoma, and non-carcinoma subtypes (P=0.106).  No difference in survival was noted between racial groups or between sexes.  Finally, those over 55 years old had worse 5-year survival than those under 55 (P<0.003).

CONCLUSION: Prognosis and treatment outcomes for primary middle ear malignancies depend on histologic subtype and age at diagnosis. The non-carcinoma and adenocarcinoma subtypes carry the best prognoses. Patients with adenocarcinoma were most likely to benefit from surgery.