Parotid-sparing irradiation for cancer of the oral cavity: maintenance of oral nutrition and body weight by preserving parotid function.

The purpose of this study was to assess the nutritional benefit of parotid-sparing irradiation, comparing the body weights of patients irradiated with parotid-sparing technique versus those irradiated with bilateral opposed photon beams, including both parotid glands in the radiation fields. One hundred fourteen patients with cancer of the oral cavity were irradiated with curative intent. Two-dimensional radiotherapy techniques sparing at least one parotid gland from the radiation beams were used to treat 31 patients (parotid-sparing techniques). Eighty-three patients were irradiated using bilateral opposed photon beams, which included both parotid glands (bilateral technique). Body weight during and after irradiation, treatment outcome, and survival were compared. Patients treated with parotid-sparing techniques maintained their nutritional intake and baseline body weight during and after irradiation. Patients treated with the bilateral technique that included both parotid glands had poor nutritional intake, leading to a more than 10% decline in their initial body weight; these patients did not regain their body weight during the 2-year follow-up period. Primary tumor control rate was higher for patients treated with parotid-sparing techniques than for patients who had both parotid glands irradiated (70% versus 48%; p = 0.05). This difference is because a higher percentage of patients treated with parotid-sparing techniques had early-stage tumors (54%) compared with patients treated with the bilateral technique (24%). When analyzed according to the tumor stage, the primary tumor control rates for patients treated with parotid-sparing techniques and for patients treated with the bilateral technique showed no difference; control rates were 93% and 87% (p = 1.00) for early-stage tumors and 42% and 36% (p = 0.75) for advanced-stage tumors, respectively. Nodal control rates in the ipsilateral side of the neck and in the contralateral side of the neck for patients treated with parotid-sparing techniques and with the bilateral technique were not significantly different-74% versus 76% (p = 0.86) and 70% versus 82% (p = 0.21), respectively. Sparing at least one parotid gland during irradiation of patients with head and neck cancer will preserve parotid function and prevent xerostomia. Patients treated with parotid-sparing techniques were able to maintain their oral nutrition and body weight, compared with patients who had both parotid glands irradiated. A higher percentage of patients treated with parotid-sparing techniques had early-stage tumors, resulting in higher rates of primary tumor control and survival in this group of patients.