Prognostic factors in parotid cancers: Clinicopathological and treatment factors influencing outcomes.

Abstract

Parotid cancers are uncommon and have a relatively long natural history. Determination of prognostic factors affecting the outcome is difficult. The primary objective was to determine the demographic, clinical, histopathology and treatment-related factors affecting overall survival (OS) in parotid cancers. The secondary objective was to study the impact of these factors on disease-free survival (DFS) and patterns of failure. Data of consecutive patients who underwent parotidectomy for primary parotid malignancy between July 2006 and April 2015 with at least 6 months of posttreatment follow-up were retrospectively retrieved. Patients whose follow-up status was known at the time of analysis were included. One hundred and sixty-five patients met the inclusion criteria. The median follow-up was 38 months. The mean OS and DFS were 141.03 and 124.38 months, respectively. Age > 45 years affected both OS and DFS (P = 0.00 and 0.002 respectively) adversely. Advanced T stage affected adversely OS in univariate (P = 0.00) but not in multivariate analysis (P = 0.91) and DFS in both univariate (P = 0.00) and multivariate analysis (P = 0.005). Nodal positivity adversely affected survival adversely in univariate (P = 0.00 for OS and DFS) and multivariate analysis (P = 0.022 for OS and P = 0.001 for DFS). Resection margin of < 5mm affected OS as compared to a margin of ≥5mm (P = 0.03). Nodal positivity is the single most important factor affecting survival in parotid cancers. A histopathological resection margin of at least 5 mm is desirable. Advanced age along with high grade, advanced T and N stages need to be considered for adjuvant treatment.