Page 12 - Sentinel lymph node biopsy in oral cavity cancer - Inne J. den Toom

Chapter 1 GENERAL INTRODUCTION Head and neck squamous cell carcinoma (HNSCC) arises from the epithelium of the upper aerodigestive tract and is mostly located in the oral cavity, pharynx and larynx. The development of HNSCC is strongly associated with risk factors as tobacco smoking and alcohol consumption, however genetic predisposition and human papilloma virus (especially in the oropharynx subsite) are also known as important key factors. HNSCC is the 9th most common cancer type worldwide, representing 3.9% of the total cancer incidence.1 In the Netherlands approximately 3000 patients are newly diagnosed each year.2 To determine the stage of HNSCC the TNM-classification system of the Union for International Cancer Control (UICC) and American Joint Committee on Cancer (AJCC) is used.3,4 With this classification the extent of tumour (T-stage), the presence of nodal metastases (N-stage) and distant metastases (M-stage) are established. The TNM- staging is based on physical examination, imaging and histopathological analysis after an eventual surgical procedure (Table 1). Staging of patients is of essential value for therapeutic and prognostic purposes (Table 2). Advanced stage disease (stage III/IV) is unfortunately diagnosed in two-thirds of all HNSCC patients. Prognosis of these patients is much worse compared to the one-third of the patients presenting with early stage disease (stage I/II). Treatment modalities for HNSCC patients are surgery, radiotherapy and chemotherapy and a combination of these is frequently used in advanced stage disease. Recently, immunotherapy is introduced as breakthrough therapy in a variety of tumour types and its potential value for HNSCC seems promising.5,6 Despite the increasing knowledge of biological characteristics of tumours and the improvements of treatment modalities, survival rates of HNSCC patients have not improved evidently over the last decades.7 This chapter describes the management of patients with early stage oral cavity cancer and a clinically node negative neck (cT1-2,N0). Besides, the concept of the sentinel lymph node biopsy procedure will be explained. Finally, the aim and outline of this thesis will be explicated and the other chapters of this thesis will be introduced. 10