Predictors and patterns of recurrence, and the impact of adjuvant radiation in early stage (pT1-2, N0) oral cavity squamous cell carcinoma: A matched pair analysis.

Abstract

e18076 Background: Early stage constitutes around 40% of all Oral cavity Squamous Cell Carcinoma (OSCC). While the role Post Operative Radiation Therapy (PORT) in advanced cases is well established, its role in early-stage disease remains controversial and is institution based. Despite oncological advances, the 5-year Disease Free Survival (DFS) fall short of 80%. Methods: An ambispective observational study was done for all early stage (pT1-2, N0) OSCC who underwent curative surgery of primary and neck from 2019 to 2024 at a tertiary oncology care centre. Patients with history of radiation, recurrence, neoadjuvant chemotherapy and positive margins were excluded from the study. Primary outcomes were Overall Survival (OS) and Disease-Free Survival (DFS). Secondary outcomes were factors associated with recurrence, radiation induced toxicity and Quality of Life. Results: 1260 OSCC were operated during the study period. 359(28%) were early stage, and 274 were eligible for analysis. 52(19.3%) patients had recurrence. 3-year-OS was 92% and 3-year-DFS was 74%. Tongue subsite (p=0.035), Depth of Invasion (DOI) >5mm (p=0.005), and Peri-Neural Invasion (PNI) (p=0.036) were significant predictors of recurrence on multi-variate analysis. Matched-pair analysis (with DOI, PNI, margins, Brandwein-Gensler score, site, stage and grade) of 65 cases (Surgery+PORT) was done with 65 controls (Only Surgery). Recurrence rates were lower in patients who received adjuvant radiation (16.9% vs 23.1%, p=0.05). Conclusions: Tongue subsite, DOI>5mm and PNI are aggressive features in early-stage OSCC. Adjuvant therapy can help to achieve improved disease control. There is a pressing need to establish definitive indications for adjuvant therapy in pT1-2, N0 OSCC. Clinical, pathological and survival analysis of group A (surgery) and group B (surgery + PORT). Before and after matched pair analysis. Variables BEFORE MATCHED PAIR ANALYSIS AFTER MATCHED PAIR ANALYSIS Total(N=274) Group ASurgery(N=171) Group BSx+PORT(N=103) p-value Total(N=130) Group ASurgery(N=65) Group BSx+PORT(N=65) p-value Site (Tongue/ FOM vs GBC) 163 (59.5%) 104 (60.8%) 59(56.3%) 0.5642 76 (58.5%) 39(60.0%) 37(56.9%) 0.3611 Stage (II vs I) 172 (62.8%) 90 (52.6%) 82(79.6%) <0.0001 91 (69.5%) 41(63.1%) 50(76.9%) 0.0862 Close Margins 105 (38%) 35 (33.3%) 70(66.7%) <0.0001 64 (48.9%) 32(49.2%) 32(49.2%) 1.000 PNI 53 (19.3%) 20 (11.7%) 33(32.0%) <0.0001 28 (21.4%) 14(21.5%) 14(21.5%) 1.000 DOI > 5 mm 117 (42.7%) 53 (31.0%) 64(62.1%) <0.0001 70 (53.4%) 35(53.8%) 35(53.8%) 1.000 High BG Risk 81 (29.6%) 36 (21.1.%) 45(43.7%) 0.0001 40 (30.5%) 20(30.8%) 20(30.8%) 1.000 Recurrence 52 (19%) 32 (18.7%) 20(19.2%) 0.8858 26 (19.8%) 15(23.1%) 11(16.9%) 0.0551 Mortality 14(5%) 07 (4.1%) 07(6.7%) 0.3260 08 (6.1%) 04(6.2%) 04(6.2%) 0.1082