Clinicopathological study and survival outcomes of sialoblastoma: A systematic review

Sialoblastoma is a rare malignant salivary gland tumor. The aim of this study was to review the available published data on sialoblastoma in a comprehensive analysis of its clinicopathologic characteristics, treatment, and outcomes. An unrestricted electronic search was performed in the following databases: MEDLINE/PubMed, EMBASE, Scopus, Web of science, and gray literature databases. Eligibility criteria included publications with sufficient clinical, imaging, and histopathological information to confirm the diagnosis of sialoblastoma. Data were evaluated descriptively and analytically. A total of 52 studies met the eligibility criteria. In total, 62 patients were evaluated. There was no gender predilection, with the parotid being the most affected primary site (n = 28; 45.2%). In the log-rank test, there was a significant increase in disease-associated survival in patients younger than 1 year of age (82.8% vs. 44.4%; p = 0.003), individuals with lesions in major salivary glands (79.4% vs. 38.5%; p = 0.005), patients without metastases (77.8% vs. 14.3%; p = 0.011), encapsulated lesions (85.7% vs. 0%; p < 0.0001), congenital lesions (83.3% vs. 25.0%; p < 0.0001), and lesions that do not show perineural invasion (89.5% vs. 40%; p = 0.035). Kaplan-Meier curves estimated overall survival and disease-free survival at 5 years of 95.5% and 68.1%, respectively. In the multivariate Cox regression model, only the presence of metastasis was identified as an independent prognostic factor (hazard ratio [HR] = 9.81; p = 0.010). Although sialoblastoma presents good prognosis, the tumor has a high recurrence rate.