Clinico-pathological and treatment-related factors influencing survival in parotid cancer

One hundred and three patients with primary parotid cancer treated surgically at the Christie Hospital, Manchester (1952–1992), were analysed to assess the influence on survival of prognostic and treatment-related factors. Thirty-seven patients were treated by surgery alone (SG), 66 received post-operative radiation (SG+RT). Median follow-up was 12 years, minimum 5 years. The 10-year disease-specific survival rates for stage I, II and III/IV were 96%, 61% and 17% respectively (P < 0.0001). The various histological types segregated into three survival patterns: low-, intermediate-and high-grade with 10-year survival rates of 93%, 41% and 50% respectively (P < 0.0001). On multivariate analysis, the factors influencing risk of cancer death in order of importance were: tumour size > 4 cm (P < 0.001), presence of nodes (P = 0.001), histology of adenoid cystic carcinoma (P = 0.01), high-tumour grade (P = 0.02) and perineural involvement (P = 0.01). Neither the extent of surgery nor the operator influenced outcome. Overall, adjuvant RT significantly reduced locoregional recurrence (SG+RT 15% vs SG 43%; P = 0.002) but not survival, although on subanalysis, there was a trend to improved survival with large cancers and high-grade tumours. Long-term survival is determined primarily by tumour characteristics, namely clinical stage and grade. Post-operative RT contributes significantly to locoregional control and probably confers some survival advantage in high-risk patients. © 1999 Cancer Research Campaign