Management of advanced parotid cancer. A systematic review.

BACKGROUND: Primary adenocarcinomas of the parotid gland are rare and account for less than 5% of all head and neck malignant neoplasms. There is considerable variation in biological behaviour within this group; low-grade tumours exhibit slow growth rates with minimal or no local invasion. High-grade tumours, however, show a high incidence of local recurrence and distant metastasis.

AIM: The purpose of this paper is to analyse the important prognostic indicators for this cancer.

METHODS: A systematic review was performed involving 19 published studies from 1987 to 2005 which included 4631 patients. T stage, grade of tumour, N stage and adjuvant radiotherapy on overall (5 year) survival were analysed as prognostic indicators.

RESULTS: T stage (p=0.041, hazard ratio 1.8 (confidence interval 1.2-2.9)), N stage (p=0.05, hazard ratio 1.1 (0.2-1.8)), and high-grade (p=0.001, hazard ratio 2.1 (1.5-2.7)) were associated with a significantly worse survival. The effect of adjuvant radiotherapy was to improve overall survival: p=0.002, hazard ratio 2.9 (1.5-4.7). The mean 5 year survival for advanced high-grade parotid cancer was 35%.

CONCLUSION: High-grade advanced parotid cancers are associated with a poor survival. Adjuvant radiotherapy is indicated in these tumours and this improves survival.