Beyond margins: TIME-infused insights into recurrence in surgically treated oral squamous cell carcinoma (OSCC).

Abstract

e18036 Background: Surgical margins are considered negative if the tumor is 3-5mm away from margins. At times patients with clear margins report back with a recurrence. There are factors beyond the margins that needs to be analyzed. The tumor immune microenvironment (TIME) plays a critical role in cancer development, progression, & control. Aim: To assess the TIME at different surgical margins and derive scoring criteria for the prognostication of recurrence in OSCC. Objective: 1) Derive a TIME score that prognosticates the recurrence-free survival (RFS) and overall survival (OS) of the patients 2) Determine the most significant margin at which TIME score can be estimated. Methods: A retrospective cohort study between 2016 to 2023. Slides of the OSCC patients who had local recurrence were evaluated for TIME parameters: a) Tumor infiltrating lymphocytes (TILS)-(CD3, CD4, CD8, FOXP3, CD57) b) Tumor associated macrophages (TAMS)-(CD68, CD163) c) Programmed death Ligand(PDL-1) d) P53 and d) Desmoplasia at - Interphase, 1mm, 3mm, 5mm, & periphery of the surgical specimen. 30 patients were included. Logistic Regression Equation (LRE) was derived for all the variables of TIME at 5 different margins. Significant margin and average RFS & OS obtained. TIME score was derived. A standard equation for RFS & OS was obtained using the TIME score. Results: Total = 30 patients. 19 were 40-60 years. Tongue was common site(36.66%). The predicted RFS = 23+/- 7 Months (M). OS = 47+/-8M. Regression model with the highest accuracy was found at 3mm margins (83.33%) for all the variables. LRE were fitted for all the variables to find the RFS & OS. LRE for RFS for each parameter at 3mm: TILS:12.4211-0.0190*CD3-0.1222*CD4-0.0979*CD8-0.0744*FXOP3-0.1809*CD57 TAMS: -0.6635+0.0768*CD68 +0.0241*CD163 PDL1: -0.4055+0.5878*PDL1+TC +2.1972*PDL1+2.1972*PDL1 DESMOPLASIA: 0.4055+0.4418* DESMOPLASIA GRADE P53: 0.4700+0.4055*P53 LRE for OS for each parameter at 3mm: TILS:0.5784+0.0262*CD3-0.0233*CD4-0.0132*CD8-0.0233*FXOP3-0.0036*CD57 TAMS: -2.8158+0.1307*CD68 + 0.0451*CD163 PDL-1: -1.3860+1.9460*PDL1 + 1.0990*PDL1 + 0.4700*PDL1 DESMOPLASIA: -0.4055* DESMOPLASIA P53: -0.8109+0.9287*P53 Value (V) From the above equations substituted in : Probability=1/1+exp(-V)), >0.5 the score is 0 : RFS (< 23+/-7 M), OS (<47+/-8 M) <0.5 the score is 1 : RFS (>23+/-7 M), OS (>47+/-8 M) Summing the score from each equation= TIME score (Max. score =5) RFS = 15.621+3.030*TIME score (p Value significant) OS = 11.481+10.699*TIME score(p Value significant) Conclusions: The TIME score can be the real-time estimator of the recurrence in surgically treated OSCC. 3mm margins have best accuracy in evaluating the RFS and OS. Average RFS & OS are 23+/-6 & 47+/-8 M respectively.