Survival and prognostic factors of parotid malignancies in Northern Italy: a multicentric study

Objective: The aim of this study is to report oncological outcomes of a multicentric cohort of surgically-treated parotid gland malignancies (PGMs) and compare them with other Italian Institutions. Methods: This is a retrospective multicentric study on surgically-treated patients with PGM. Overall survival (OS), disease-free survival (DFS) and disease-specific survival (DSS) at 5 years were calculated. The Cox proportional hazard model was used for uni- and multivariate analyses. A qualitative review of the Italian literature was performed. Results: One-hundred and six patients were included. Negative prognostic factors included deep lobe involvement, size > 4 cm, advanced stage, margin status, histological grade, nodal involvement and extranodal disease. Parotidectomy extent did not influence DSS or DFS for T1-T2 superficial tumours. The occult lymph node metastasis rate was 30.8%. Neither elective neck dissection (END) nor elective neck irradiation (ENI) influenced DFS or DSS. Conclusions: Deep lobe removal in pT1-T2 superficial tumours may not always be necessary. END and ENI did not show a significant impact on prognosis, despite a high incidence of occult nodal metastasis. Further studies are needed to fully evaluate the impact of these therapeutic options in subgroups of patients with PGMs.