ESTRO 2025 - Abstract Book

S1070

Clinical – Head & neck

ESTRO 2025

3223

Poster Discussion Prognostic Impact of Lymph Node Ratio in Locally Advanced Oral Cancer Patients: Insights from a Randomized Trial Subgroup (NCT00193843) Anuj Kumar 1 , Sarbani Ghosh Laskar 1 , Shwetabh Sinha 1 , Samarpita Mohanty 1 , Ashwini Budrukkar 1 , Monali Swain 1 , Pankaj Chaturvedi 2 , Gouri Pantvaidya 2 , Shivakumar Thiagarajan 2 , Chandrashekhar Dravid 2 , Sudhir Nair 2 , Deepa Nair 2 , Anuja Deshmukh 2 , Richa Vaish 2 , Vidisha Tuljapurkar 2 , Poonam Joshi 2 , Rathan Shetty 2 , Arjun Singh 2 , Kumar Prabhash 3 , Vanita Noronha 3 , Amit Joshi 3 , Nandini Menon 3 1 Department of Radiation Oncology, Tata Memorial Centre, Homi Bhabha National Institute, Mumbai, India. 2 Department of Surgical Oncology, Tata Memorial Centre, Homi Bhabha National Institute, Mumbai, India. 3 Department of Medical Oncology, Tata Memorial Centre, Homi Bhabha National Institute, Mumbai, India Purpose/Objective: The Lymph Node Ratio (LNR), defined as the ratio of positive to total dissected lymph nodes, is an emerging prognostic factor in head and neck cancers. This study evaluated the impact of high vs. low LNR on survival outcomes in locally advanced oral cancer patients using data from the Oral Cavity Adjuvant Therapy (OCAT) Randomized Controlled Trial (NCT00193843). Material/Methods: We analysed data from 679 patients with positive lymph nodes out of 900 patients enrolled in the OCAT trial on locally advanced resectable oral cancers, conducted between June 2005 and March 2013. Patients were assigned to one of three treatment arms post-surgery: 5-day Radiation Therapy (RT), 6-day RT, or Concurrent Chemoradiotherapy. The remaining patients were excluded due to uninvolved lymph nodes. Patients were categorised by LNR as Low (<0.1) or High (≥0.1) 1 . Kaplan-Meier analysis was used to calculate overall survival (OS). Statistical significance between groups was assessed using the log-rank test. Results: The median age of the cohort was 45 years. Primary tumour sites included gingivo-buccal complex (61.4%) and tongue/floor of mouth (38.6%). About 87.5% were T3-T4, 64.4% N2-N3, with 71.7% having extracapsular extension (ECE). The median follow-up was 48 months. The low LNR group demonstrated a median OS of 40 months and a 3 year OS of 52.3%, whereas the High LNR group had a median OS of 14 months and a 3-year OS rate of 39.2% (p < 0.0001), indicating poorer outcomes for high LNR patients. When stratified by ECE status, those with High LNR and ECE had significantly worse outcomes (median OS of 11 months, 3-year OS of 31.4%) compared to Low LNR with ECE (median OS of 31 months, 3-year OS of 48.2%) (p <0.001). In contrast, patients without ECE showed similar survival regardless of LNR, with a median OS of 60 months and 3-year OS rates of 61.2% (High LNR) and 62.3% (Low LNR) (p 0.856). These findings suggest that ECE is a more decisive predictor of survival than LNR alone. Conclusion: Data from the OCAT trial suggest that LNR is a significant predictor of overall survival in locally advanced oral cancer patients. High LNR, particularly in the presence of ECE, is associated with poorer outcomes. For patients without ECE, LNR may have less prognostic impact, questioning the necessity of aggressive therapy in this subgroup. Further studies are recommended to explore how LNR and ECE can guide tailored treatment approaches in head and neck cancer patients.

Keywords: Adjuvant therapy, Lymphatic spread, Survival

References: 1. Ding D, Stokes W, Eguchi M, et al. Association Between Lymph Node Ratio and Recurrence and Survival Outcomes in Patients With Oral Cavity Cancer. JAMA Otolaryngol Head Neck Surg. 2019;145(1):53–61. doi:10.1001/jamaoto.2018.2974