ESTRO 2021 Abstract Book

S789

ESTRO 2021

TNM stage (4>3>2>1)

1.13(0.89-1.43) 0.302

GTV total^

1.11(1.05-1.16) <0.001

1.07(1.01-1.14) 0.018

RDW (>13.8% vs. ≤13.8%) 1.28(1.12-1.47) <0.001

1.09(0.94-1.26) 0.260

NLR (>2.099 vs. ≤2.099)

1.11(1.06-1.18) <0.001

1.05(0.98-1.13) 0.135

^per increase by 10 a The multivariate analysis includes variables that were significantly correlated with OS in a univariate analysis at a p < 0.05 level of significance, and only the most statistically significant in case of many significant corresponding variables. Figure Log-rank curves for overall survival of patients with squamous cell carcinoma of the oropharynx stratified by RDW and NLR level.

Conclusion The survival is significantly lower in patients with increased RDW and NLR. However, the relatively low sensitivity and specificity of these indices, as well as lack of statistical significance in multivariate models, suggest that their clinical value is limited. PO-0946 Treatment outcomes of carcinoma buccal mucosa treated with definitive accelerated radiotherapy C.T. Kainickal 1 , G. Babu 2 , R.R. Kumar 2 , M. Rafi 1 , A. M.P 1 , L.M. Nair 1 , F. N 1 , P. George 3 , R. K 4 1 Regional Cancer Centre, Department of Radiation Oncology, Thiruvananthapuram, India; 2 Regional Cancer Centre , Department of Radiation Oncology, Thiruvananthapuram, India; 3 Regional Cancer Centre, Department of Cancer Epidemiology & Biostatistics, Thiruvananthapuram, India; 4 Regional Cancer Centre, Department of Radiation Oncology, Thiruvananthapuram,, India Purpose or Objective To retrospectively evaluate the clinical profile and treatment outcomes of Carcinoma Buccal Mucosa patients treated with Definitive Radiotherapy by Accelerated Radiotherapy (5250 cGy/15F) schedule at Regional Cancer Centre, Trivandrum, South India. Materials and Methods Records of all patients who received accelerated Radiotherapy (5250 cGy/15F) for carcinoma buccal mucosa from January 2010 to December 2016 were retrospectively reviewed and analysed. 517 patients included in the study. Mean age of the study population was 63 years. Three hundred and thirty nine (339) (65.6%) were males. 42 (8.1%), 127(24.6%), 235(45.5%) 113 (21.9%) patients had Stage I, II, III and IVa disease respectively. The survival estimates were generated using Kaplan–Meier method. Results Median follow up is 77.4 months. Four hundred and seventy three patients attained remission. Forty four (8.5%) patients did not obtain clinical remission following radiotherapy, of which 19 patients underwent salvage surgery. 128 (24.8%) patients had relapsed. 46 patients underwent salvage surgery among the relapsed patients .The disease free and overall survival at 4 years for the entire cohort was 73.1% and 84% respectively. The Four year overall survival for stage I, II, III and IVa was 85.6%, 87.4%, 83.9% and 79.4% respectively and disease free survival was 83.3 %, 77.3%, 73% and 64.7% respectively. Nodal status was found to be a significant factor affecting disease free survival in multivariate analysis (p value -0.02). Fifty three (10.3%) patients had developed osteoradionecrosis of mandible. Thirty six (7%) patients developed second malignancy of which thirty patients had second malignancy in upper aero digestive tract. Three (0.6%) had developed third malignancy during their follow up period. Conclusion Excellent outcome could be achieved in cancer of the buccal mucosa treated with radical accelerated Radiotherapy (5250 cGy/15F) in centres with high patient load. Salvage rates are poor following accelerated Radiotherapy.