Clinico pathological features and treatment outcomes in parotid malignancies

Abstract

Neoplasms that arise in the salivary glands are relatively rare, yet they represent a wide variety of both benign and malignant histologic subtypes. Salivary gland neoplasms most commonly appear in the sixth decade of life. The salivary glands are divided into 2 groups: the major salivary glands and the minor salivary glands. The major salivary glands consist of the following 3 pairs of glands: the parotid glands, the submandibular glands, and the sublingual glands. The minor salivary glands comprise 600-1000 small glands distributed throughout the upper aero digestive tract. Among salivary gland neoplasms, 80% arise in the parotid glands, 10-15% arises in the submandibular glands, and the remainder arises in the sublingual and minor salivary glands. Tumors of the salivary glands form one of the most heterogeneous groups of oncological pathology. They constitute a substantial proportion of all tumors of the oro-facial region. Head and neck tumors represent approximately 5% of human neoplasms, and out of these, salivary gland neoplasms constitute 10%.

Objective To evaluate clinicopathological features and treatment outcomes of parotid gland malignancies in patients who attended Ocean Road Cancer Institute (ORCI) from 2009-2016.

Methodology A Retrospective study design was employed among all patients who had been diagnosed and confirmed histologically with malignant Parotid tumor referred to and treated at ORCI from January 2009-December 2016. Analysis of this retrospective study determined the sociodemographic factors, clinico-pathological features, treatment outcomes of surgery, radiotherapy, chemotherapy and assessment of 2 years overall survival of parotid malignancies from January 2009 to December 2014. In this study, the retrospective secondary data was extracted from the patient medical files and data was collected in the data collection form. The study was conducted at ORCI in Dar es Salaam.

Results Out of 94 patients with histologically confirmed parotid gland malignancy, more males were affected compared to females with the ratio of 1.18:1 and the mean SD age of patients was 51.9years. Adenocarcinoma was the most common malignant tumor n=37 (40%) followed by squamous cell carcinoma n=18 (19.1%) and the left parotid gland being the most affected site. 44 cases (46.8%) had pathological grading, grade IV accounting for majority of the grades (27.3%). Stage IV was presented the most n=72 (76.5%) and 8.5% presented with metastasis at diagnosis. 31% of patients were subjected to surgery while 69.1% were deemed to be unfit for surgery due to advanced disease. Radiotherapy was received by n=82 (95.2%) with 13 patients (14%) subjected to curative intent and 69 patients (86%) subjected to palliative intent. 2 year overall survival for the curative cohort from 2009-2014 is 23% and 11% for the palliative arm. The 2 year overall survival of parotid gland malignancy treated at ORCI is 12%. Conclusion Clinico-pathological presentation of parotid gland malignancy seen in this study differs from other studies probably due to geographical variations. More males are affected than women, especially in the middle ages. Adenocarcinoma was the most frequent histology. Two years Overall survival from 2009 to 2014 was 12%. Late stage presentation was seen as a problem that needs to addressed in order to maximize the effectiveness of the treatment, and improve the overall survival. Treatment modalities need to be standardized across health facilities in Tanzania.