12 Chapter 1 Management and histopathological evaluation of primary OSCC and regional lymph node metastasis Generally, the management of OSCC includes single modality surgery, or a combination of surgery and adjuvant radiotherapy with or without systemic therapy (11). Primary tumor resection The main goal of surgery is complete resection of the tumor with negative margins, as margin status is one of the most important variables associated with loco-regional control and survival (5, 12, 16-20). The extent of resection is estimated using information on tumor size assessed by preoperative imaging, as well as visual inspection and palpation performed during surgery. Ultimately, the definitive margin status is determined by the pathologist days after surgery (21, 22). This lack in intra-operative communication between surgeon and pathologist, results in inadequate margins in 30-85% of the procedures (23). To reduce these numbers, efforts are made to develop procedures that facilitate intra-operative margin assessment using either the resected specimen or the tumor bed. These techniques include: frozen section analysis, optical techniques (e.g. Raman spectroscopy), fluorescence, conventional imaging techniques (e.g. ultrasound), and cytological assessment (21). Regional lymph node dissection For patients diagnosed with OSCC with clinically positive cervical lymph nodes or cT3T4N0 tumors, primary tumor resection with neck dissection is indicated. The major question is what to do with patients presenting with cT1T2N0 tumors. Although neck dissection is a safe procedure, it is associated with high morbidity (5, 24). Therefore, elective neck dissection (END) is recommended if the risk of occult regional lymph node metastasis (RLNM) is 20% for patients with early-stage tumors that are cN0 (25). In this situation, END is either therapeutic when pN0. However, when pN+, it can help in determining whether adjuvant therapy is necessary (see below). Alternatives for END are observation, elective radiotherapy, or sentinel lymph node biopsy (SLNB) (5). The National Comprehensive Cancer Network recommends the use of DOI in making decisions on END, as it is an established predictor for occult RLNM (11). Since DOI with a cut-off value (> 4 mm) strongly predicts the presence of occult RLNM, this cutoff value is used within the Erasmus MC in making decisions on END (11, 26, 27). Yet, the DOI is determined days after the excision of the primary tumor during final pathological evaluation (15). As such, cancers with DOI of > 4 mm, require a second
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