Koos Boeve

95 Lymphatic drainage patterns of oral maxillary tumors Figure 2. Four examples of lymphatic drainage patterns in oral maxillary cancer. To illustrate our cohort, 4 of the 8 included patients with oral maxillary cancer are shown. (1A–1C) Patient #10 with a small tumor in the midline was planned for a bilateral sentinel lymph node biopsy (SLNB). On both the transversal (B) and coronal (C) slides of the single photon emission CT (SPECT)-CT scan, are the sentinel lymph nodes (SLNs) visible in the cervical levels. (2A–2C) Patient #8, planned for a contralateral SLNB, with a tumor close to the midline (big radioactive spot on the coronal slides B and C) and bilateral SLNs in the cervical neck levels at the SPECT-CT scan. (3A–3C) Patient #7 with a melanoma in the hard palate close to the midline and planned for a contralateral SLNB. This is the patient in whom a retropharyngeal SLN was visible on the SPECT-CT scan (3B, red arrow), besides the SLNs at the cervical level (3C). (4A–4C) Patient #2 with an upper gum tumor on the left side. This is the patient with a retromaxillary SLN (4B, red arrow), besides a cervical SLN at level II (4C, green arrow; hardly visible at this slide). In patient #1, 1 of the 3 resected sentinel lymph nodes at level II was tumor positive by histopathological examination with a metastasis size of 6.6 mm in diameter and without extranodal growth. All additional harvested lymph nodes were negative for regional metastasis. DISCUSSION Because of ongoing debate on the route of lymphatic drainage of maxillary OSCC, we studied the lymphatic drainage pattern of oral maxillary cancer via preoperative lymphoscintigraphy. Insights in lymphatic drainage patterns of oral maxillary cancer are important to determine if an END is adequate treatment of the neck in maxillary OSCC. In 10 patients, sentinel lymph nodes were detected by lymphoscintygraphy at cervical level and these sentinel lymph nodes could be harvested during surgery on the ipsilateral or contralateral side at cervical levels I, II or III. Eight patients (73%) had exclusively cervical located sentinel lymph nodes and only in 2 patients (18%) parapharyngeal sentinel lymph nodes were detected on lymphoscintigraphy, in combination with cervical sentinel lymph nodes. Therefore, the common location of the sentinel lymph nodes of oral maxillary cancer at the cervical neck levels, indicates the potential use of the SLNB procedure in maxillary OSCC. Because of the retrospective study design, lymphoscintigraphy information from both neck sides was not available for all patients. When a (elective) neck dissection was indicated at the ipsilateral side compared to the tumor, only the contralateral lymphoscintigraphy information was available. Three patients (numbers 3, 9 and 11) were not excluded despite of previous neck treatment by neck dissection. A prospective study design with lymphoscintigraphy of both neck sides and without previously treated patients would be