Abstract
The incidence of parotid carcinoma is lower than that of squamous cell carcinoma of the head and neck. Parotid carcinomas are rare, representing about 2% of all head and neck malignancies. In addition, there are many histological types differing in the grade of malignancy. We have employed specific strategies to diagnose/treat parotid carcinoma over the past 20 years. Many reports support that prognostic factors for parotid carcinomas are TNM, local invasion, histologic differentiation (grade), perineural invasion, and facial palsy. In these factors, it is generally accepted that stage and histological grade are the most important factor. Therefore, planning of therapy should be carried out according to each stage and histopathologocal type because each has different tumor activity. Fine needle aspiration biopsy of the salivary gland is an accepted, sensitive and specific technique in the diagnosis of the tumors. However, its accuracy is generally poor, especially in low/intermediate grade carcinoma. Since it is difficult to diagnose histopathological type in each case, we attempt to classify parotid carcinoma into three groups, low, intermediate, and high grade carcinoma. In case of the same group, we can perform almost the same operation planning. In the neck dissection for N0 patients, elective neck dissection (END) may not be necessary in low-grade patients. However, currently, END should be performed in all parotid carcinoma patients because of the low accuracy of grade diagnosis. It was previously thought that cancer of the salivary gland was radioresistant. However, more recent reports suggest otherwise. Postoperative radiotherapy is superior to that for surgery alone. Indications of radiotherapy are the following: high grade cancer, perineural spread of tumor, node metastasis, positive surgical margin, and aggressive cancer.
