A Prospective Observational Study on Neck Lymph Node Mapping in OralCancers Using Methylene Blue Dye

a) Introduction/Background of Research Project

 The head & neck region is one of the most complex and diverse part of the body both anatomically and histologically. The term ‘head and neck cancer’ refers to the malignancies of upper aerodigestive tract including the lips, oral cavity, oropharynx, sinonasal tract (including nasopharynx), larynx, hypopharynx, and salivary glands and skin over the head and neck region. Malignancy arising in these regions are also diverse, though most commonly squamous cell carcinoma.

Though lip and oral cavity cancer consists of only 2% of total cancer incidence worldwide, in India it is far more common, with an annual incidence of approximately 10.26% of total cancer incidence among both sexes and the most common malignancy in males.

Though the etiology appears to be multifactorial, the most commonly implicated factors are tobacco and alcohol. Other factors such as immunosuppression and HPV infection are also related to oral SCC, especially in younger population. Tobacco consumption may be in the form of smoking or smokeless tobacco chewing.

The presentation may range from asymptomatic premalignant lesions (erythroplakia or leukoplakia) to extensive disease with fungating mass or facial disfigurement. The majority of patients present in a locally advanced Stage III/IV in India. An early detection and appropriate management can lead to about 80% cure rates with significantly improved quality of life and functionality.

Surgery remains the mainstay of treatment for cancers of the oral cavity for decades. In contrast, radiotherapy or multimodality treatment is instituted for mainly in advanced cases to achieve an optimal therapeutic outcome and prognosis. The primary and adjuvant therapy is dictated by the T & N stage of the disease and carefully addressing the neck is equally important as the treatment of the primary site. The surgical options for the neck are comprehensive, functional or selective neck dissection. In current scenario it is debatable whether or not early stage N0 oral cancer patients should undergo elective neck dissection.

Sentinel LN biopsy is gaining more importance as it identify occult cervical metastasis and guides elective neck dissection thus decreasing morbidity. There are several methods and agents used for SLNB. In developing country like India, SLN mapping by methylene blue dye is very much appropriate as it is low cost, less allergic and easily available. But there are very limited studies internationally and nationally which uses only blue dye. The aims of our study is to address this issue by assessing the technical feasibility and accuracy of SLN mapping in patients with node-negative oral squamous cell carcinoma using methylene blue dye only.