Patterns of recurrence and second primary tumors in oral squamous cell carcinoma treated with surgery alone

The aim of the present study is to review the recurrence patterns and incidence of second primary tumors (SPTs) in patients with oral squamous cell carcinoma (OSCC) who underwent surgery alone without postoperative adjuvant therapy. Data on patients recorded in the head and neck cancer registry of Cathay General Hospital were reviewed. A total of 72 patients with T1-3N0 OSCC who underwent surgery alone were included. Among the 72 patients, 44 had T1 tumors, 22 had T2 tumors, and 6 had T3 tumors. The 5-year overall survival (OS) rate was 77.3%, the recurrence-free survival rate was 74.1%, and the SPT-free survival rate was 73%. Eighteen (25%) patients had disease recurrence (regional recurrence in nine patients, local recurrence in seven patients, and locoregional recurrence in two patients). Most patients with local recurrence alone (6/7 patients, 85.7%) could be salvaged with treatment. However, locoregional control was obtained in only five (45.5%) of 11 patients with neck recurrence after surgical salvage therapy. At the time of analysis, 20 patients developed SPTs, and 15 (75%) of the SPTs were in the oral cavity. The annual incidence of SPT was 5%. Neck recurrence and SPT were associated with 48.4% and 24.4% lower 5-year OS rates, respectively. Multivariate analysis revealed that neck recurrence was a significant risk factor for low OS (p = 0.008). Neck recurrence was the most important prognostic factor for OS. The incidence of SPT development was high. Regular and long-term monitoring for recurrence and development of SPTs is necessary to improve the survival rate.