Koos Boeve

61 SLNB in early oral cancer Table 2. Association between SLN metastasis size and additional metastases in modified radical neck dissection lymph nodes SLN status n (%) MRND lymph node status p-value pN0, n (%) pN+, n (%) Isolated Tumour Cells 7 (29) 7 (37) 0 (0) 0.024 Micrometastases 6 (25) 6 (32) 0 (0) Macrometastases 11 (46) 6 (32) 5 (100) Abbreviations: SLN: sentinel lymph node. MRND: modified radical neck dissection. pN0: LNs negative for metastases. pN+: LNs positive for metastases. Follow-up and regional recurrence Overall the median FU was 32 months (IQR 21-47, Range 2-104, Table 1). All patients with a follow-up <10 months died. In total, 8 (9%) patients of this cohort died. Three patients died of disease, two 10 months and one 21 months after the initial treatment. Local recurrence and second primary tumours, with or without regional recurrence, were seen in 9 (10%) cases. Isolated regional recurrence was detected in 5 (5%) patients. One of these patients had IRR after a positive SLN and subsequent neck dissection at that neck side. The other 4 patients were diagnosed with IRR after 4, 6, 9 and 19 months. Their tumour, treatment and recurrence characteristics are shown in Table 3. The first patient had a positive ipsilateral SLN and was 4 months later diagnosed with level I and level II IRRs at the contralateral side. Revision of the SPECT-CT images and the conventional CT images of the IRR did not reveal new insights. The second patient had ipsilateral negative SLNs and was diagnosed with level Ib and level IV IRRs after 9 months. Revision of the SPECT-CT images of this patient showed a lymph node with a diameter of 7 mm without radioactivity just at the inside of the mandibular angle in level Ib. This lymph node was most likely not resected during the SLNB procedure and could be the same as the IRR lymph node. The third patient had a positive contralateral SLN. IRR occurred on the ipsilateral side, which was SLNB negative and was therefore not treated by MRND. Revision of the lymphoscintigraphy images revealed a low signal in level Ib at the ipsilateral side, what might be a missed SLN. The fourth patient had a negative SLN in level II and was diagnosed with IRR in level Ib, both ipsilateral. Revision of the SPECT-CT scan showed a LN within the radioactive hotspot of the floor of mouth tumour of this patient. Most likely, this is the same LN in which the IRR was diagnosed (Figure 2). Due to the four IRRs, the SLNB detected occult metastases with 85% sensitivity and 94% NPV.