EP-1016: Can Weight loss alert adaptive planning to reduce parotid gland dose? A correlative study to guide adaptive radiation
S. Sarkar, A. Mahata, R. Ray, S. Guha, I. Mallick, R. Achair, S. Sinha, S. Chatterjee
Radiotherapy and Oncology
Materials and Methods: Type of study : Descriptive study 24 Eligible patients with age less than 61 years were included in this study from October 2011. Informed consent was obtained. Dental prophylaxis was carried out in all before the treatment. The patients were treated after evaluation and according to the stage of the disease. 13/24patients (54.16%) were locally advanced and 11/24 patients (45.83%) were early stage. All of them received treatment as per protocol. Early stages T1/T2 and N0
... ere treated with EBRT (bilateral opposing fields or anterolateral wedge field to face and neck) dose of 44 Gy followed by 6 Gy with off cord (total dose 50Gy/25#) was given to the primary as well as the regional lymph nodes of upper neck. This was followed by HDR interstitial brachytherapy boost of 2.5Gy per fraction or 3.5Gy per fraction for 6 fractions twice daily with 6 to 8hrs interval between two fractions. Low anterior neck field (for lymph nodes) received 50 Gy per 25 fractions. Locally advanced T1-T3 with N1, N2a, N2b or T3N0 diseases were treated similarly as mentioned above along with concurrent chemotherapy Cisplatin (70 mg/m 2 every 3 weeks) and 16 Gy Electron boost/photon boost (if nodes are involved). Under general anaesthesia, trocars and hollow needles were inserted as guide tubes in and around the tumour 1cm apart in a single or multiple planes through which plastic tubes were threaded. These tubes were then secured by buttons. On 2 nd post op day patients were simulated with CT scan. The CT images were transferred to the treatment planning system. The target was delineated in the planning system and 3D treatment plan was made to deliver the dose to the target. The effect of treatment was assessed by clinical examination as well as by imaging techniques if required on follow up. Results: High-dose-rate brachytherapy was tolerated by all patients. Only 2/24 (0.08%) patients developed bleeding complication. Local control was seen in 83.33% of patients among which 9/11 patients (81.8%) were in early stage and 11/13 (84.61%) patients were in locally advanced stage. (This is an ongoing study.) Conclusions: High-dose-rate brachytherapy as a boost for patients with primary squamous cell carcinomas of the oral cavity will help improve local control. It limits the volume of tissue exposed to high doses of radiation therapy. It has showed effective local control in early and locally advanced stages.