ESTRO 2023 - Abstract Book

S299

Sunday 14 May 2023

ESTRO 2023

Conclusion In appropriately selected HNSCC patients with lung-only oligometastatic disease, SBRT may improve clinical outcome prolonging time to progression and to systemic treatments. Distant metastases from HPV-related primary HNSCC should be tested for p16/HPV status given the clinical implications of HPV positivity for diagnosis and treatment. PD-0398 Clinical outcomes of Thyroid Sparing Radical Chemoradiation in the treatment of Head and Neck cancer V.K.V. Gade 1 , A. Bahl 1 , A. Rastogi 2 , A.S. Oinam 3 , S. Ghoshal 4 , N.K. Panda 5 1 Post Graduate Institute of Medical Education and Research, Department of Radiotherapy and Oncology, Chandigarh, India; 2 Post Graduate Institute of Medical Education and Research , Department of Endocrinology, Chandigarh, India; 3 Post Graduate Institute of Medical Education and Research , Department of Radiotherapy and Oncology, Chandigarh, India; 4 Post Graduate Institute of Medical Education and Research , Department of Radiotherapy and Oncology, Chandiagrh, India; 5 Post Graduate Institute of Medical Education and Research , Department of Otorhinolaryngology and Head and Neck surgery, Chandigarh, India Purpose or Objective Radiation-induced hypothyroidism after radical head and neck cancer treatment has the potential to worsen the quality of life of patients. Thyroid-sparing techniques are sparingly employed in locally advanced head and neck cancers. This pilot study was designed to evaluate the clinical outcomes of Thyroid Sparing Simultaneous Integrated Boost Volumetric Modulated Arc Radiotherapy (SIB-VMAT) in the treatment of Stage III and IV Head and Neck cancers. Materials and Methods This two-arm pilot study recruited patients of Stage III and IV squamous cell carcinomas of the head and neck for treatment with radical chemoradiation using SIB-VMAT technique. Patients in the study group received radiotherapy by thyroid-sparing SIB-VMAT technique to a dose of 70 Gy and 59.4 Gy (to the gross disease and subclinical disease) in 33 fractions over 6 ½ weeks with concurrent three weekly cisplatin (100mg/m2 on days 1,22,43). The thyroid constraint employed was V50Gy<75%. The control group consisted of patients treated with the same schedule without thyroid constraints. Thyroid profile was evaluated at the end of radiotherapy, 6 months, 9 months after radiotherapy, and at the last follow-up. Survival analysis was done using the Kaplan-Meir method and the Progression Free Survival (PFS) was compared using the log-rank test. Results Twenty-six patients were evaluated in this study (thirteen in each arm). There were twenty-five males (96.2%) and one female patient (3.8%). The median age was 51.5 years (range 35-65 years). Thirteen (50%) patients had Stage III and the other half were Stage IVA at diagnosis. All patients were euthyroid at diagnosis. The median follow-up duration was 20.7 months. On last follow up the mean TSH, T3 and T4 values in the non thyroid sparing and the thyroid sparing group were