Clinical Significance and Indication for Surgical Treatment of Occult Cervical and Intraglandular Nodal Involvement in Parotid Malignancy.

PURPOSE

Surgical management, including the extent of surgery, for patients with parotid malignant tumors has been challenging. The aims of the present study were to identify the factors associated with survival, estimate the incidence of occult nodal and intraglandular metastases, and determine the predictive influence on overall and disease-free survival, with consideration of the surgical extent.

PATIENTS AND METHODS

We implemented a retrospective cohort study and identified incident cases with parotid malignant tumors from 2003 to 2016 at a single quaternary medical care and cancer center. A medical record analysis was performed retrospectively of the patient and histopathologic data. The predictor variables were age; tumor grade; T stage; N stage; facial nerve palsy; perineural, vascular, and lymphovascular invasion; completion parotidectomy; elective neck dissection; and pN0 versus pN+. Overall and disease-free survival were evaluated as primary and secondary outcome variables. Data analysis was performed as a time-to-event analysis (Kaplan-Meier method).

RESULTS

A total of 102 patients with parotid carcinoma had undergone surgery from 2003 to 2016 at the University Hospital Freiburg, Germany; 69 patients had undergone completion parotidectomy (total, 36; radical, 33). A total of 13 patients had occult intraparotideal lymph node metastases after elective completion parotidectomy. All the patients who had undergone elective neck dissection and clinically had had no nodal involvement (cN0) had had no pathologic lymph node metastases found (pN0). However, the predictive factors for cervical nodal involvement were high-grade tumors, locally advanced tumors (cT3-cT4), and the presence of intraparotideal nodal metastases.

CONCLUSIONS

The rate of occult cervical metastases in the present study was surprisingly low (0%). However, owing to the various predictive factors, elective neck dissection should be performed for high-grade or locally advanced (stage T3-T4) parotid malignoma. Moreover, we highly recommend performing completion parotidectomy for all high-grade tumors and also for locally advanced (stage T3-T4) low-grade tumors, owing to the >12% of occult intraparotideal metastases found in the present study.