Carcinoma of the parotid gland.

BACKGROUND: The low incidence and heterogeneity of histiotypes of primary parotid carcinomas makes these tumors histologically and epidemiologically difficult to evaluate. The present study reviews a single institution's experience in the treatment of primary parotid carcinomas during the last 10 years.

METHODS: The charts of 98 consecutive patients who had a primary parotid carcinoma and who received primary curative treatment were analyzed retrospectively. The tumors were grouped into high-grade and low-grade malignancies. The effect of treatment modalities on locoregional control, the incidence of locoregional recurrences and distant metastases, and survival rates are evaluated and compared between high- and low-grade malignancies.

RESULTS: High- and low-grade malignant tumors were observed in 50 and 48 cases, respectively. Lymph node metastases were detected in 25 of 98 (25%) patients, of whom 8 of 22 (22%) clinically NO staged patients underwent elective neck dissection. In 24 of 26 resected facial nerves, a histologic tumor infiltration was confirmed, in 14 high-grade and 10 low-grade tumors. Local recurrence developed in 13 patients and was associated in 7 with high-grade and in 6 with low-grade tumors. All but 1 of the low-grade malignancies with local recurrence did not receive postoperative irradiation. Regional recurrence developed in 11 patients and distant metastases developed in 10, 3 in combination with a neck recurrence and 1 with a local recurrence. The survival rate at 5 years for low- and high-grade carcinomas was 87% and 56% and the disease-free survival rate 72% and 48%, respectively.

CONCLUSIONS: The incidence of occult metastases in clinically N0-elective neck dissection was 22%. A routine elective neck dissection in all N0 parotid carcinomas is suggested. There is no statistically significant difference between low- and high-grade tumors as for the rate of local recurrence and, as all except one of the low-grade malignancies with local recurrence did not receive postoperative irradiation, postoperative irradiation is not only suggested for high-grade carcinomas but also for T2 to T4 low-grade carcinomas.