3598 - Early Recurrence in Patients Treated with Surgical Resection and Postoperative Radiotherapy in Patients with Squamous Cell Carcinoma of the Head and Neck

K. Abumansour^1,2, D. R. Wilke³, M. Kim⁴, A. L. Caissie⁵, L. R. Best⁴, M. Rajaraman⁴, H. Hollenhorst⁵, S. Snow⁴, M. Rigby⁴, S. M. Taylor², J. Trites⁴, and N. Lamond⁴; ¹King Abdulaziz University, Jeddah, Saudi Arabia, ²Dalhousie University, halifax, NS, Canada, ³Capital Health, Halifax, NS, Canada, ⁴Dalhousie University, Halifax, NS, Canada, ⁵Dalhousie University/Nova Scotia Health, Halifax, NS, Canada

Purpose/Objective(s): To determine the pattern of relapse, outcomes, and predictors of patients with head and neck squamous cell carcinoma (HNSCC), treated with surgery who had evidence of early recurrence prior to postoperative radiotherapy (PORT). Materials/

Methods: A retrospective review was performed for patients with squamous cell carcinoma of the oral cavity, oropharynx, larynx, hypopharynx, and nasal cavity (HNSCC), treated with curative intent surgery followed by PORT, with or without systemic therapy between 2007 and 2019. Patients were classified into 3 groups: (1) Early recurrence patients, who presented with recurrence at either the primary site, or the neck, before or shortly after planned PORT started, (2) Later recurrence patients, who recurred locoregionally, after completing PORT, with no evidence of recurrence before or during PORT, and (3) patients who, during and after PORT, had no evidence of local recurrence. Multivariable analysis (MVA) was performed to identify predictors of early recurrence, local recurrence, and overall survival (OS).
Results: Three hundred and thirty-eight patients were treated with surgery followed by PORT; 33 patients (9.76%) had early recurrence before PORT. On MVA, smoking (at any time) (OR, 3.916 (1.539-9.967); p=0.0102), N category (pN3, OR 2.956 (1.427-6.126); p<0.0001), perineural invasion (OR 2.180 (1.219-3.899); p=0.0086) and increasing time from surgery to starting radiotherapy (OR 1.316(1.181-1.467); p<0.0001), were predictive of early recurrence. The local recurrence rate in patients with early recurrence was 60.5% (95%CI: 39.3-76.4%) at 5 years, compared to 15.6% (95%CI:11.6-20.2%) in patients who did not have early recurrence. The five-year OS for patients with early recurrence, later recurrence, or no local recurrence was 15.3% (95%CI: 4.9-31.1%), 16.5% (95%CI: 7.1-29.2%) and 69.8% (95%CI: 63.3-75.4%), respectively (p < 0.0001).
Conclusion: Patients with early recurrence have significantly higher rates of local failure, distant metastases, and poor overall survival, compared to patients without early recurrence. Treatment paradigms investigating strategies to improve local failure and distant failure appear warranted in this unique patient group.