Overview

The role of radiotherapy in salivary gland tumors:

This is a diverse group of tumors that are primarily treated with surgery. The commonest site for a salivary gland tumor is the parotid gland; however submandibular gland tumors are more likely to be malignant.

There are many histopathological types of salivary gland cancer such as adenoid cystic carcinoma, mucoepidermoid carcinoma adenocarcinoma, carcinoma ex pleomorphic adenoma. Adenoid cystic carcinoma has some peculiar characteristics, which are mentioned in a separate page.

Radiotherapy is indicated in all patients suffering from adenoid cystic carcinoma and in others in histologies if high-risk features are noted in the examination of the tissue removed surgically. Radiotherapy for salivary gland tumors is unilateral i.e., treatment is directed only to the affected side of the face and neck. Radiotherapy may also be used to treat inoperable lesions.

Proton therapy has a significant advantage in the treatment of this tumor in that radiation dose received by the opposite side of the face and neck is substantially less, of the order of more than 80% reduction in dose. This result is less inflammation of the inner lining of the cheek, palate, tongue and less dose to the voice box. Salivary gland tumors often occur in young adolescents and adults and the reduction in the radiation being received by the opposite side has an additional advantage of decreasing the risk of developing a radiation induced cancer.