Clinicopathological Behavior and Oncological Outcomes of Malignant Parotid Tumors in a Pakistani Population.

Introduction The incidence of salivary gland tumors is influenced by geographical and racial factors resulting in diverse histology.  While salivary gland tumors account for a low proportion of head and neck cancers, most malignant tumors of the salivary gland are located in the parotid gland. The goals of this study are to describe the clinicopathological behavior of malignant parotid tumors and explore oncological outcomes related to survival in our Pakistani tertiary care cancer hospital. Methods We conducted a retrospective analysis of 209 patients diagnosed with malignant parotid tumors from 2004 to 2016. Data such as demographics, age, gender, histology, grade, clinical and pathological stage, surgical treatment types and adjuvant modalities used were analyzed using SPSS software version 20. We used Kaplan Meier curves to analyze survival data. Results The median patient age at diagnosis was 40 years, and the ratio of men to women was 1.2:1. Mucoepidermoid carcinoma was the most common histological variant (with a 50% incidence rate) followed by adenoid cystic carcinoma (13%), and adenocarcinoma (10%). Histology has further categorized these malignant tumors into low (34%), intermediate (28%), and high (21% ) grades. The American Joint Committee on Cancer, seventh edition, clinical staging was Stage I (21%), II (28%), III (15%), and IV (34%). The 5-year survival was 68%, and the 10-year survival was 45%. Conclusion Mucoepidermoid carcinoma is the most common malignant parotid histology in our patient population. Advanced age, increased T stage (size > 4 cm), high-grade histology, and cervical nodal involvement decrease overall survival. Open biopsies, piecemeal excisions, and delayed presentation for radiotherapy post-surgery may also have role in adverse outcomes in these malignancies.