Survival outcome and prognostic factor analyses in early tongue cancer patients treated with surgery alone

Background: The long-term outcome for early stage tongue cancer is generally good, however patients who suffered from local recurrence experienced a worse outcome than those who had not. The purpose of this study was to analyze long-term outcome for early stage tongue cancer patients treated by surgery alone for potential factors in predicting any subsequent relapse. Methods: The inclusion criteria for this retrospective study involved previously untreated, biopsy-proven squamous cell carcinoma (SCC) of the tongue, clinical stage T1-2N0M0 and patients who had received surgery alone. From February 2007 to January 2015, the chart records and images of 199 eligible patients were reviewed. Results: After a medial follow-up period of 89 months, we discovered 53 recurrences and 34 deaths. The 5-year overall survival (OS) and locoregional failure-free survival (LRFFS) rates were 83.9% and 72.4%, respectively. Univariate and multivariate analyses revealed that a poorly differentiated histology, depth of invasion (DOI) >5 mm, and perineural invasion (PNI) affected both OS and LRFFS. Patients with an absence of any risk factors (poorly differentiated histology, invasion depth over 5 mm, and PNI) experienced significantly better OS (5-year rates, 92.0% vs. 72.7%, P=0.0001) and LRFFS (5-year rates, 76.8% vs. 66.6 %, P=0.0382) than those with at least one of the risk factors. Conclusions: An overall relapse rate of 26.6% was observed for patients with early tongue cancer treated by surgery alone. Patients with risk factors (poorly differentiated histology, DOI >5 mm, and PNI) should be considered for postoperative adjuvant therapy in future trials. 8