OP021: Tumor thickness as predictor of prognosis in carcinoma of tongue

Abstract

Introduction Squamous cell carcinoma of the oral tongue is one of the most common cancers of the oral cavity. The over all survival (OS) varies from 80% to 30% and depends on several factors like T stage, nodal status and grade. Tumor thickness more than 4 mm is often reported to have significantly higher occult nodal metastasis compared to thinner ones. However, only a few studies have correlated the tumor thickness with survival. Most of these studies were done on a limited number of patients spanning more than 10 years. Hence, in this study we analyzed several factors including thickness that can influence survival in tongue cancers. Patients and methods The electronic medical records of patients with pathologically proved squamous cell carcinoma of the tongue operated at Tata Memorial Hospital, a tertiary cancer center, between January 2007 and June 2010 were screened for the study. Cases were selected based on the following eligibility criteria: (1) Treatment nai¨ve; (2) surgery as the first-line treatment; (3) carcinoma of the tongue being the index lesion. Of the total 877 patients screened, 586 patients were eligible for the study. The clinical and demographic details as well as the histopathological data of these patients were obtained from the hospital maintained medical records. Information regarding patient survival and disease status was also retrieved from medical records and by telephonic interview. Follow-up details were available for 498 (85%) patients with a median follow-up of 18 months (range: 1–63 months). Results Out of the 586 patients included in the study, 416 (70%) were men and 170 (30%) were women, aged between 20 and 80 years (mean: 47 years, median: 48 years). Majority of these patients (402, 68.8%) had moderately differentiated tumors, followed by poorly differentiated in 152 (25.9%) and well differentiated in 39 (6.6%) cases. All patients had surgery as the first line of management. These patients were staged based on the American Joint Committee on Cancer (AJCC) staging system 6. Clinically 69 (12%) patients had T1 disease, 286 (49%) had T2 disease, 126 (21%) had T3 disease and 105 (18%) had T4 disease (ref table 2). 110 (31%) cases who were clinically node negative (N0) had occult nodal metastasis on final histopathological examination. Of the 311(53.7%) cases who had pathologically positive nodes, 205 cases (65.9%) had extracapsular spread (ECS). With a median follow up of 18 months, the median disease free survival was 17 months, and median over all survival was 18 months. 195 patients developed recurrence, predominantly regional (85 patients). While ECS, PNI, gender and thickness affected the disease free survival, Age, ECS, Pathological T stage and tumor thickness were found to be significantly affecting the overall survival on multivariate analysis. Tumor thickness more than 10 mm affected the overall survival significantly. Conclusion Apart from the known clinical factors like nodal metastasis, ECS, perineural invasion, tumor thickness is an important factor for prognosis in oral tongue cancers.