Analysis of treatment results for oral tongue cancer

The study reports the results of treatment of oral tongue cancer with five different treatment modalities with long-term follow-up.

Retrospective study of 332 patients with oral tongue cancer treated in the Departments of Otolaryngology-Head and Neck Surgery and Radiation Therapy at Washington University School of Medicine (St. Louis, MO) from 1957 to 1996.

Patients with biopsy-proven squamous cell carcinoma of the oral tongue who were previously untreated and were treated with curative intent by one of five modalities and who were eligible for 5-year follow-up were included. The treatment modalities included local resection alone, composite resection alone (with neck dissection), radiation therapy alone, local resection with radiation therapy, and composite resection with radiation therapy. Multiple diagnostic, treatment, and follow-up parameters were studied using standard statistical analysis to determine statistical significance.

The overall 5-year disease-specific survival rate (DSS) was 57% with death due to tumor in 43%. The 5-year cumulative disease-specific survival probability (CDSS) was 0.61 (Kaplan-Meier) with a mean of 17.5 years and a median of 30.1 years. The DSS by treatment modality included local resection (73%), composite resection (61%), radiation therapy (46%), local resection and radiation therapy (65%), and composite resection with radiation therapy (CR/RT) (44%). Overall, local resection had a significantly improved DSS and CR/RT had a decreased DSS that was related to the stage of disease being treated. In treating stage IV disease, CR/RT produced a more significantly improved CDSS than the other treatment modalities. Recurrence at the primary site was as common as recurrence in the neck. Eighty-nine percent of recurrences occurred within the first 60 months. Recurrence significantly decreased survival. DSS was significantly improved in patients with clear margins of resection. Metastasis to a distant site occurred in 9.6% of patients. Twenty-one percent of patients had second primary cancers, and 54% of these patients died of their second primary cancer.

Significant improvement in DSS was seen in patients with clear margins, early stage grouping and clinical (pretreatment) tumor stage, and negative nodes. Significant decrease in DSS was seen in patients with close or involved margins, advanced stage grouping and clinical (pretreatment) tumor staging, positive clinical (pretreatment) node staging, and tumor recurrence. Obtaining clear margins of resection is crucial because it significantly affects survival. A minimum of 5 years of close monitoring is recommended because of the high incidence of second primary cancers.