Comparing Survival Outcomes and Recurrence Patterns in Oral Cavity Squamous Cell Carcinoma (OCSCC) Patients Treated With Curative Intent Either With Adjuvant or Definitive (Chemo)radiotherapy.

AIMS: To assess the survival outcome and recurrence patterns of locally advanced oral cavity squamous cell carcinoma (LA-OCSCC) treated with radical surgery followed by adjuvant or definitive upfront (chemo)radiotherapy. MATERIALS AND METHODS: This is a single United Kingdom cancer centre retrospective analysis on LA-OCSCC treated with curative intent. All OCSCC patients treated between 2012 and 2022 were included with groups treated with either postoperative adjuvant (chemo)-radiotherapy or definitive (chemo)radiotherapy. Patients who recurred before starting adjuvant treatments were excluded. RESULTS: Patient characteristics: Ninety-nine (73.9%) patients were treated with primary surgery followed by adjuvant (chemo)radiotherapy and 35 (26.1%) patients treated in the definitive group, respectively. SURVIVAL: The median progression-free survival was 17 months and 15 months for adjuvant and definitive groups, respectively (P value of 0.947). Median overall survival was 61 months and 43 months for adjuvant and definitive groups, respectively (P value of 0.154). Smoking history is an independent negative predictor for survival. Recurrence: Median time to local and distant recurrence was 17 months and 15 months, respectively. In the adjuvant group, the local recurrence rate is 26% and the distant recurrence rate is 32%, compared with the definitive group at 26% and 34%, respectively. The rate of recurrence is highest in the first two years after diagnosis. Distant recurrence in LA-OCSCC can happen without prior local-regional recurrence. CONCLUSION: Patients with surgically resectable LA-OCSCC patients treated with primary radical surgery followed by adjuvant (chemo)radiotherapy had better survival outcomes compared with patients treated with upfront definitive (chemo)radiotherapy. The pattern of recurrence of LA-OCSCC is aggressive and without curative surgery the rate of survival is poorer.