2017 Section 7 Green Book

C. Schilling et al. / European Journal of Cancer 51 (2015) 2777 e 2784

Fig. 1. Overall survival for SNB þ versus SNB biopsy (p Z 0.00083). SNB, sentinel node biopsy.

Fig. 3. Overall survival by metastasis type: isolated tumour cells (I) versus macrometastasis (Ma) versus micrometastasis (Mi) (p Z 0.0318).

SNB causing tumour spillage and in turn neck recurrence. Two- and 5-year overall survival in early oral and oropharyngeal carcinoma is in the region of 82% and 76%, respectively [20,22] . In this study, overall crude (88%) and DSS (94%) are unlikely to change signifi- cantly and suggest strongly that SNB does not adversely affect outcome. An FNR of 14% is similar to that reported in a meta-analysis of 25,000 melanoma patients (12.5%) [23] and 20% FNR in 10-year follow- up of the Multicenter Selective Lymphadenectomy Trial (MSLT) trial in melanoma [24] . However, this is on the borderline of acceptability and we should aim to reduce this to the 7% FNR accepted in breast cancer [25] . Further analysis of the factors associated with a false-negative biopsy is warranted but initial review of our data suggests that operator factors are principally responsible for the FNR. It is well estab- lished that there is a learning curve to the SN tech- nique [11] . It is of particular note that previous studies [9,11] indicated that SNB was less reliable for tumours in the floor of mouth presumably due to the close proximity of the injection site to the primary draining nodes. The same association was not found in this study. The major positive patient benefit of SNB is that in this series 71% of patients were spared neck dissection with consequent improved function and reduced morbidity [26,27] . There were also 47 patients with midline tumours who by convention would have received bilateral neck dissection. In this group, only eight underwent bilateral and eight unilateral dissection based on positive SN. A low complication rate as well as

Fig. 2. Overall survival for 0, 1, or 2 positive sentinel nodes (p Z 0.000016).

been missed by conventional treatment of ipsilateral neck dissection. In head and neck cancer, historically, there has been concern that biopsy of suspected neck metastasis would facilitate dissemination of tumour in the neck. A systematic review [20] of 109 papers calculated regional recurrence rates of 13% in surgically treated early-stage oral cancer. A further review of 164 [21] patients with pT1 e T2 tongue SCC staged pN0 after END reported a regional recurrence rate of 18%. The results of SENT when reported in an identical way show the neck recurrence rate for SNB and SNB þ and the total group were 5%, 15% and 7.5%. The low rate of regional recurrence argues against

126