Salivary gland carcinoma: independent prognostic factors for locoregional control, distant metastases, and overall survival: results of the Dutch head and neck oncology cooperative group.

BACKGROUND: We analyzed the records of patients with malignant salivary gland tumors, as diagnosed in centers of the Dutch Head and Neck Oncology Cooperative Group, in search of independent prognostic factors for locoregional control, distant metastases, and overall survival.

METHODS: In 565 patients, we analyzed general results and looked for the potential prognostic variables of age, sex, delay, clinical and pathologic T and N stage, site (332 parotid, 76 submandibular, 129 oral cavity, 28 pharynx/larynx), pain, facial weakness, clinical and pathologic skin involvement, histologic type (WHO 1972 classification), treatment, resection margins, spill, perineural and vascular invasion, number of neck nodes, and extranodal disease. The median follow-up period was 74 months; it was 99 months for patients who were alive on the last follow-up.

RESULTS: The rates of local control, regional control, distant metastasis-free and overall survival after 10 years were, respectively, 78%, 87%, 67%, and 50%. In multivariable analysis, local control was predicted by clinical T-stage, bone invasion, site, resection margin, and treatment. Regional control depended on N stage, facial nerve paralysis, and treatment. The relative risk with surgery alone, compared to surgery plus postoperative radiotherapy, was 9.7 for local recurrence and 2.3 for regional recurrence. Distant metastases were independently correlated with T and N stage, sex, perineural invasion, histologic type, and clinical skin involvement. Overall survival depended on age, sex, T and pN stage, site, skin and bone invasion.

CONCLUSIONS: Several prognostic factors for locoregional control, distant metastases, and overall survival were found. Postoperative radiotherapy was found to improve locoregional control.