Clinical behaviours and prognoses of high- and low-risk parotid malignancies based on histology

To report 5-year survival in patients with primary parotid malignant tumours and assess the impact of various factors on survival or local control among diverse histologic groups.

A total of 65 patients with primary parotid malignant tumours who had surgery between 2003 and 2014 were identified. Demographic characteristics including age, T stage, N stage and clinical or pathological performance were analysed. According to risk stratification (based on pathology), 65 primary parotid malignant tumours were divided into high-risk (23, 35.38%) and low-risk (35, 53.85%) groups. Overall survival (OS) and disease-free survival (DFS) were recorded by the Kaplan-Meier methods.

The 5-year overall survival rate for primary parotid malignant tumours was 70.9%. Patients older than 60 years with fixed mass, pain, facial-nerve palsy and high-grade N stage had adverse OS and DFS. Upon multivariable analysis, facial-nerve palsy (HR 24.59; 95% CI 2.338-178.446; P = 0.002) was the only independent predictive factor for OS. Patients with high-risk parotid malignant types were more likely to have tumour pain, facial-nerve palsy (Chi-square test: < 0.0001 and 0.02), lymphatic metastasis and local/regional recurrence (Chi-square test: 0.008 and 0.012).

Compared with low-risk parotid carcinoma, tumours with high-risk histological features tend to need aggressive surgical extirpation, neck dissection and postoperative radiotherapy.