The Tongue cancers

Tongue cancers account for over 25% of oral cavity SCCs and most commonly arise in the oral portion or anterior two-thirds of the tongue on the lateral edge or ventral surface. Infiltration of the underlying tongue musculature occurs early. The intrinsic tongue muscles are loosely arranged and endowed with a rich vascular and lymphatic supply, which may explain the high rate of regional metastases. Prognosis is directly related to the degree of infiltration and the presence of regional metastases. The biologic aggressiveness of small (< 4 cm) tongue cancers is noteworthy and is reflected in higher rates of occult regional metastases than those of similarly staged lesions arising from other oral sites. Occult nodal metastases are present in 30% to 40% of early lesions. Approximately 40% of patients have clinical evidence of node metastases at diagnosis. Primary-echelon node drainage is to the upper deep cervical lymphatics; however, involvement of middle and lower neck nodes (levels III and IV) is not uncommon. Bilateral nodal involvement can occur with cancers of the tip or the midline of the tongue. Locoregional recurrence in patients with tongue cancer accounts for 60% to 70% of cancer deaths. Distant metastases account for 15% of deaths, and second primaries account for 20% to 40%.

The management of carcinomas of the tongue has been significantly influenced by a better appreciation of the aggressiveness of small deeply infiltrative lesions, the high rate of occult lymph node metastases, and an interest in improving treatment without compromising oral function. Although surgical excision alone has been the mainstay of treatment, combined surgery and adjuvant radiation therapy to include the primary site and regional nodes is commonly used for most advanced cancers (stages III and IV) and is being used increasingly for small stage II cancers that exhibit pathologic indicators of lymph node metastasis or perineural invasion.

For stage I cancers, surgical excision is effective and expeditious, with good preservation of function. For stage II lesions that are infiltrative, hemiglossectomy or partial glossectomy achieves excellent tumor control rates and should be combined with modified dissection of neck nodes (supraomohyoid dissections) to provide accurate information about staging and determination of the need for adjuvant treatment. Hemiglossectomy may result in some functional morbidity in terms of articulation and deglutition. Because of this, radiation therapy may be used in selected cases. Nevertheless, surgery should remain the mainstay of treatment in oral tongue malignancies. For radiation to be as effective as surgery in controlling these cancers, interstitial brachytherapy combined with external radiation is essential. Radiation doses of 80 to 85 Gy are generally given via external megavoltage radiation or in combination with brachytherapy. Such high doses, however, are associated with osteoradionecrosis, fibrosis, and impaired function, and as a result, primary treatment of oral cavity SCCs with radiation therapy is falling out of favor. Interstitial treatment requires precise placement and spacing of implants. Accurate dosimetry is enhanced by using afterloading techniques in which the radioactive source is inserted into previously placed hollow tubes. Tracheostomy at the time of implantation should be considered because of the potential development of tongue edema after implantation. Occult or apparent neck disease is usually treated using external radiation or radiation combined with neck dissection.