Efficacy of Computerized Tomography (CT) in Identification of Clinically Un-detectable Lymph Nodes in Patients with Oral Squamous Cell Carcinoma - an Observational Study

Background: The most common malignant tumour of head and neck region is Oral squamous cell carcinoma and is the third most common malignancy in India. The most common mode of metastasis is through the cervical lymph nodes. Detection of tumours is mostly done clinically by direct visual examination. The complexity in predicting the presence of metastatic disease in clinically negative necks has lead to wide spread use of elective neck dissection. This present study is intended to evaluate the status of clinically not detectable lymph nodes using.

Computerized Tomography: (CT) which might help in determining the prognosis and treatment plan and also to compare the accuracy between the clinical examination and CT.

Methods: Forty patients who have been histopathologically diagnosed as Oral squamous cell carcinoma were included in the study The patients were subjected to clinical as well as CT examination. The findings of both examinations were correlated with pathological findings from the neck dissection.

Results: Number of True positives detected by clinical examination (CE) versus CT is 7 and 13 respectively (p=0.17). Number of True negatives detected by CE versus CT is 18 and 18 respectively (p=1). Number of False positives detected by CE versus CT is 5 and 5 respectively (p=1). Number of False negatives detected by CE versus CT is 10 and 4 respectively (p=0.1).Sensitivity for CE versus CT is 41.1% and 68.4% respectively (p=0). Specificity for CE versus CT is 78.2% and 78.2% respectively (p=1). Positive Predictive Value for CE versus CT is 58.3% and 72.2% respectively (p=0.001). Negative Predictive Value for CE versus CT is 64.2% and 75% respectively (p=0.001). Accuracy of CE versus CT is 62.5% and 77.5% respectively (p=0.001).

Conclusion: The present result indicates that CT is an important image tool for detection of clinically occult lymph nodes of head and neck in patients with oral squamous cell carcinoma and statistically significant over the clinical examination regarding the sensitivity, true predictive value, false predictive value and over all accuracy.