Patterns of lymph node metastasis and the management of neck dissection for parotid carcinomas: a single-institute experience

BackgroundThere is no consensus about the indications and range of neck dissection in patients who have parotid carcinoma, with elective neck dissection for cN0 disease being particularly controversial.MethodsThis study retrospectively reviewed 185 patients with newly diagnosed parotid carcinoma who were treated at our department between September 1999 and August 2018.Results50 of the 185 patients had lymph node metastasis, including 7.7%, 12.2%, 36.0%, and 55.8% of patients with T1, T2, T3, and T4 disease, respectively. When classified by histological grade, 5.7% of patients with low/intermediate-grade disease had lymph node metastasis versus 55.0% of patients with high-grade disease. Multivariate analysis revealed that the histological grade and T classification were independent predictors of lymph node metastasis. Occult metastasis was found in 8 out of 73 clinically node negative patients undergoing neck dissection. The most common site of cervical metastasis was level 2, followed by the periparotid nodes, level 3, and level 4.ConclusionElective neck dissection may be most appropriate for parotid carcinoma patients with high grade disease and/or an advanced T classification. Because preoperative evaluation of the histological grade of parotid carcinoma has limited reliability, it is important to decide the indications and range of neck dissection from the results of frozen section biopsy.