Differences in clinical features and prognosis between orbit adenoid cystic carcinoma and adenocarcinoma: a study from the SEER 18 database

Purpose: To analyze the differences in clinical features, treatment methods, prognosis, and etiological factors between lacrimal gland, adenoid cystic carcinoma (LGACC), and orbit adenocarcinoma. Material and Methods: All cases of LGACC and orbit adenocarcinoma between 1975 and 2016 were obtained from the US National Cancer Institute’s Surveillance, Epidemiology, and End Results (SEER) database. Results: The 3-, 5-, and 10-year overall survival (OS) rates for 118 LGACC cases were 82.2%, 70.2%, and 51.7%, respectively. The 3-, 5-, and 10-year OS rates for 29 orbit adenocarcinoma cases were 76.3%, 51.2%, and 51.2%, respectively. There was no statistically significant difference in the overall survival rate between LGACC and adenocarcinoma (P=0.566). Univariate analysis showed that the proportion of deaths was higher with increased age and year of diagnosis in LGACC (P=0.010 and P=0.000), while the death rate was higher for poorly differentiated adenocarcinoma (P=0.020). The survival rate for LGACC was lower in patients ⩾60 years of age than in those <60 years of age (P=0.035). There was no significant difference in survival rate between adenocarcinoma patients ⩾60 years and <60 years old (P=0.102). There was no significant correlation between the degree of tumor differentiation and the survival rate for LGACC or adenocarcinoma (P=0.401 or P=0.098, respectively). Conclusion: There is no significant difference in prognosis between LGACC and adenocarcinoma. The degree of tumor differentiation is not associated with prognosis for either LGACC or adenocarcinoma.