Squamous Cell Carcinoma of the Tongue
Squamous cell carcinoma (SCC) is the most common tongue mass and carcinoma, accounting for more than 90% of all malignant tongue tumors. 1
Histologic Predominance
- Squamous cell carcinoma or its variants represent over 90% of oral cavity and pharyngeal cancers, including tongue malignancies. 1
- The overwhelming predominance of SCC applies to both the oral tongue (anterior two-thirds) and base of tongue (posterior third). 2
Anatomic Distribution Within the Tongue
- The lateral border of the tongue is the most common specific location for oral tongue SCC, presenting in the majority of cases regardless of patient risk factor profile. 3
- Base of tongue lesions comprise a distinct subset with different clinical behavior, typically presenting at more advanced stages and with poorly differentiated histology compared to oral tongue tumors. 2
Risk Factor Profile in Tongue SCC
The etiology differs significantly based on anatomic location:
Oral Tongue (Anterior Two-Thirds)
- Tobacco and alcohol use account for 75-85% of oral tongue cancers, with synergistic effects when both exposures are present. 4, 5
- Approximately 79% of patients with tongue SCC have smoking history, and 58% consume alcohol daily. 2
- Male predominance exists with a 1.5:1 to 2:1 male-to-female ratio. 6, 2
Base of Tongue (Posterior Third)
- HPV infection, particularly HPV-16, is the predominant etiologic factor for base of tongue carcinomas, with an odds ratio of 22.4 for HPV-16 specifically. 4
- HPV-positive oropharyngeal cancers (including base of tongue) increased more than 3-fold from 1988 to 2004, while HPV-negative cases decreased by 50% during the same period. 5
- In the United States, 80-95% of oropharyngeal cancers are now attributable to HPV infection. 5
Clinical Presentation Patterns
Oral Tongue Lesions
- Localized discomfort is the most common presenting complaint (66.5% of cases), typically present for up to 6 months before diagnosis. 2
- Ulceration is noted by 70.2% of patients at disease onset, though only 13% initially experience pain. 7
- By the time of presentation, nearly all patients experience pain, indicating disease progression during the delay to diagnosis. 7
Base of Tongue Lesions
- Neck masses, dysphagia, ear pain, and weight loss are more characteristic presenting symptoms. 2
- These tumors present at more advanced stages, with approximately 85% of all tongue cancer patients presenting with stage III or IV disease. 7
Important Clinical Caveat
A significant minority (20-40%) of younger patients (≤45 years) with oral tongue SCC have no history of tobacco or alcohol exposure, suggesting alternative etiologic pathways. 8, 3 This is particularly true for female patients, who more commonly present without traditional risk factors. 7 These patients without tobacco/alcohol exposure tend to be older at diagnosis and paradoxically may have worse cancer-free survival rates (38% vs 60% 5-year rate) compared to those with exposure history. 8