Objective: The aim of the study was to assess the results of curative treatment of patients with squamous cell carcinoma of the tongue and to evaluate survival and predictive factors of recurrence.
Patients and methods: A series of 309 patients with squamous cell carcinoma of the tongue treated with curative intent was studied from January 1988 to December 1999. The percentage of oral tongue cancer was 82.2 and the percentage of cancer of base of the tongue was 17.8. Most patients underwent surgical procedure alone or combined with radiotherapy (92%). We performed 252 neck dissections. Bilateral dissections were performed for cancer of the apex linguae, cancer of the base of the tongue, for patients with N2c neck disease and whenever the primary tumor site crossed the median line. Twenty-five patients (8%) were treated with radiation therapy alone. Mean follow-up was 55 months. The functional results were assessed within a minimum of 10 months postoperative follow-up.
Results: In 45.2%, there was histological evidence of node invasion with 53.5% of extracapsular node spread in the neck specimens. Extracapsular node spread did not influence survival or recurrences. Occult cervical metastasis in an elective neck dissection in clinically negative necks was found in about 20% of patients with 47% of extracapsular node spread (41% for cancer of mobile tongue and 80% for those of base of the tongue). About 23% of patients with cancer of base of the tongue staged N0 had histological node invasion in controlateral neck nodes. The postoperative mortality rate was 0.9%. The rate of complications was 17%. The cancer recurred in 41.7% of all cases. Twelve percent of all patients had second primary cancers of the upper aerodigestive tract. The overall survival and non-recurrence rates at 2 and 5 years were higher in cancer of oral tongue than in cancer of base of the tongue. Survival rates were better when neck nodes were clinically or histologically negatives and in early-stage carcinomas. Non-recurrence rates were better when nodes were clinically or histologically negatives and when margins of exeresis were not involved. The functional results were better in oral tongue cancer than in base of the tongue cancer.
Discussion: Prognosis (survival and non-recurrence rates and functional results) of squamous cell carcinomas of oral tongue was better than prognosis of those of base of tongue. We recommend an aggressive surgical procedure even in patients with neck classed N0 (with reservations for T1 lesions with small depth of invasion): an ipsilateral supraomohyoid neck dissection for cancer of oral tongue and a bilateral supraomohyoid neck dissection for cancer of base of the tongue, cancer of oral tongue which crosses the median line of the oral cavity and cancer of the apex linguae. Postoperative radiotherapy must be performed when margins are positives and/or when nodes are involved with or without extracapsular spread.