387P - Radiation dose to contralateral parotid during treatment of carcinoma buccal mucosa

Abstract

Background: To compare the contralateral parotid gland dose during radiation treatment of carcinoma buccal mucosa with 3 Dimensional Conformal Radiotherapy (3D-CRT) vs. Parotid sparing Intensity Modulated Radiotherapy (IMRT). Methods: Ten consecutive lateralized carcinoma of the oral cavity patients treated with a prospective management using ipsilateral irradiation were studied. This included 4 radical and 6 postoperative oral cavity carcinomas, with Stage T1-T2, N0-N2b disease. Five patients were treated with 3D-CRT and five with IMRT. The dose received by contralateral parotid gland was assessed by volumetric analysis. Results: Dose-volume histograms (DVH) showed the mean dose to contralateral parotid was 896.6 cGy (range: 0.5-10 Gy) with 3D-CRT and 503.8cGy (range: 0.4-4 Gy) with IMRT. With IMRT 97%-105% of the prescribed dose was received by 95% of the target volumes. Mean dose to the PTV Primary site was 67.8 Gy (range, 65-71 Gy) for primary RT and 60.5 Gy (range: 55-66 Gy) for post-operative RT. The mean dose to the PTV Node (ipsilateral lymph nodes) was 50.8 Gy (range: 49-53 Gy). Conclusions: There is a considerable increase in the mean dose of contralateral parotid in 3DCRT compared to IMRT. Parotid sparing IMRT helps reducing the radiation dose received by salivary glands. Legal entity responsible for the study: CBCC-Chennai, Saveetha University, Chennai. Funding: Has not received any funding. Disclosure: All authors have declared no conflicts of interest.