Tongue is a complex anatomical site and its form and function are crucial for efficient swallowing, speech and appreciation of taste. In past different methods of treatment have been employed but tongue has remained a difficult area to assess and treat. The survival in carcinoma of the tongue is poor compared to other subsites in oral cavity.

At presentation, 44% of patients had T₂ tumour followed by T₃ in 20% (Table 2). Clinically 34 patients were found to be neck node positive of which 26 (34.7%) were cN₁, 6 (8%) were cN_2b and 2 (2.7%) were cN_2c. Histologically 33 cases were found to have positive neck nodes, of which majority (16; 21.3%) were pN_2b. The T and N stage distribution is detailed in table 2. Cervical lymph node metastasis was present in 47.1% of T₁ tumours, 24.13% of T₂ tumours, 63.6% of T₃ tumours and 61.1% of T₄ tumours (Table 3). Histologically 18 cases were true positive for nodal metastasis while 26 cases were true negative giving a sensitivity of 54.5% and specificity of 61.9% for clinical examination of the neck (Table 4). Synchronous discontinuous operations were performed in all cases. None of the patients had a positive resection margin, however the margin was close (2–5 mm) in 11 cases. Neck was managed by vein preserving neck dissection in 27 cases (36%) and supraomohyoid neck dissection in 22 cases (29.3%) (Table 1). It was observed that the nodal involvement in ipsilateral level II was highest (63.6%), followed by the involvement of level I (51.5%), level III (18.2%) and level IV (15.2%) (Table 1). Table 2 shows the distribution of nodes at different levels of the neck in varying combination. Skip metastasis to level III / III and IV occurred in 5 cases. On histopathological examination, only one patient had bilateral positive nodes. These nodes were located at level I bilaterally and the patient had undergone bilateral vein preserving neck dissection (Table 1). A total of 59 patients received adjuvant radiotherapy, radiotherapy was given to 32/34 patients with N+ disease, or extranodal spread. Nine patients with T1N0 disease and 5 patients with T2N0 disease and one patient each with T1N1 and T2N1 disease did not receive adjuvant radiotherapy.

It was seen that only 35.6% of T₁ and T₂ lesions showed nodal metastasis where as 62.3% of the larger tumours showed metastasis (Table 3). Previous studies [9,6] support our finding that tumour size is a predictor of lymph node metastasis though they propose that tumour thickness is a more reliable factor. This is further explained by DiTroia (1972) [10], who points to difficulty for the tumour emboli to form in small calibre lymphatics of the superficial areas, compared with wider lymphatic of deeper tissues. However, tumour thickness is a radiological or histological parameter, which cannot be assessed preoperatively by clinical examination or biopsy.

In our study, sensitivity and specificity of clinical examination was poor suggesting that clinical examination is of limited use in predicting cervical nodal metastasis. This is in accord with previous studies [5,6]. One option would be to look for a more reliable methods to asses the neck. Sajeeda et al (2000) [11] documented that ultrasonography is not only useful in detecting neck nodes but is also useful in assessing the nodal characteristic and the degree of vascular invasion. Takashima et al (1997) [12] demonstrated ultrasound guided fine needle aspiration to have 93.7% diagnostic accuracy. Computed tomographic (CT) scanning too is very useful for the purpose of early detection of neck metastasis [13]. Magnetic resonance imaging (MRI) on the other hand has been found to have little advantage over clinical examination as the soft tissue contrast resolution reported by MRI is inadequate to detect minimal morphological changes in lymph nodes [14].

The technique of sentinel node biopsy is gaining popularity. Surgery on the primary tumour often modifies lymphatic drainage, so sentinel node biopsy is useful when primary tumour and neck are operated at the same time [15]. If the treatment decision has to be based on the present sensitivity and specificity of clinical examination, then a minimum selective neck dissection should be carried out for all node negative necks where primary is being treated by surgery as primary modality. Studies have documented that ipsilateral level I, II and III neck dissection is an adequate diagnostic procedure for staging of the clinically node negative neck in early oral tongue cancer [16,17]. Its diagnostic role cannot be replaced by preoperative radiological screening and intraoperative frozen section sampling.

T₁ and T₂ tumours show a similar, significantly higher disease free survival compared to T₃ and T₄ tumours, even though the number in the present study is small the conclusions can be drawn with conviction from these results as shown in earlier studies on smaller sample size [18]. Brown et al (1989) [19] too have shown similar results. Nodal metastases too significantly correlate with disease free survival as also documented by Woolgar et al (1999)[6]. Similar results were seen in the present study as well, where tumour size, nodal status and surgery as primary modality were found to be a significant predictor of disease free survival.