Do Lymph Node Ratio and Histopathologic Parameters Have Any Prognostic Value in Primary Parotid Gland Carcinomas?

Objective: To analyze the demographic characteristics and the pathological results of neck dissection in primary parotid gland (PG) cancer patients, and to investigate the effects of histopathological parameters (perineural invasion, lymphovascular invasion, and extracapsular spread), neck metastasis, stage and lymph node ratio (LNR) on survival.

Methods: Patients who underwent parotidectomy for malignant PG tumors between 2000 and 2019 years were retrospectively reviewed from the medical records. Thirty patients who were treated with parotidectomy and neck dissection were included in the study. Lymph node ratio was calculated as the ratio of the number of metastatic lymph nodes (LN) to the total number of excised LNs. Tumor stage, regional LN metastasis, LNR, perineural invasion, lymphovascular invasion, and extracapsular spread were reviewed for the effects on survival with the Kaplan-Meier analysis.

Results: The study included 17 (57%) male and 13 (43%) female patients. Their mean age was 67.93±16.90 years (range, 50-85 years). The average number of the excised LN was 26.03±11.79 (range, 3-50). Mean LNR was 0.16±0.26. The Kaplan-Meier analysis showed that neck metastasis (p=0.001) and LNR (p<0.001) were associated with shorter survival times compared to perineural invasion (p=0.818), lymphovascular invasion (p=0.154), extracapsular spread (p=0.410) and stage (p=0.294). In multivariate COX regression analysis, only LNR had a statistically significant difference (p=0.027) compared to the other parameters.

Conclusion: The present study suggests that LNR and neck metastasis are associated with shorter survival times in PG cancers. Lymph node ratio can be used as a prognostic marker in these patients.