شارما بوشان جروفر, سونال كوشي, جورج شارما, ديبيت abstract: Cervical lymph node metastasis affects the prognosis and overall survival rate of and therapeutic planning for patients with head and neck squamous cell carcinomas (HNSCCs). However, advanced diagnostic modalities still lack accuracy in detecting occult neck metastasis. A sentinel lymph node biopsy is a minimally invasive auxiliary method for assessing the presence of occult metastatic disease in a patient with a clinically negative neck. This technique increases the specificity of neck dissection and thus reduces morbidity among oral cancer patients. The removal of sentinel nodes and dissection of the levels between the primary tumour and the sentinel node or the irradiation of target nodal basins is favoured as a selective treatment approach; this technique has the potential to become the new standard of care for patients with HNSCCs. This article presents an update on clinical applications and novel developments in this field. A s opposed to primary tumours, metastasis is responsible for the high mortality rate of most cancer patients; moreover, cancer cells primarily invade the regional lymph nodes before spreading to other parts of the body.
Keywords1 Genetic instability results in tumour cell heterogeneity, leading to the emergence of metastatic clones and dissemination of the cancer from the primary tumour site.2 Malignant cells metastasise due to an interaction between the host factors and tumour cells. Genes related to the extracellular matrix, adhesion, motility and protease inhibition constitute a significant part of the metastatic process. The migration and invasion of cancer cells into the lymphatic system is governed by a variety of intricate genotypic, phenotypic and microenvironmental processes. After entering the lymphatic draining channels, the tumour cells metastasise to the regional lymph nodes in the neck and form the metastatic foci.4 Macrometastases refer to lymph nodes that appear suspicious on clinical or radiographical examinations; in contrast, nodal metastases-which are not detectable by imaging methods or physical examination-indicate occult or subclinical metastasis. Hermanek microscopically differentiated occult metastases into macrometastases (metastatic deposits of >2 mm), micrometastases (metastatic deposits of <2 mm) and isolated or small clusters of tumour cells (metastatic deposits of <0.2 mm).5 Isolated tumour cells (ITCs) can also be defined as a cluster of ≤200 tumour cells visible on one histology slide; these cells can further be categorised into those detectable by light microscopy, immunohistochemistry or molecular methods.6 Chemoradiation or elective neck dissection (END) should be considered in patients