Koos Boeve

42 Chapter 2 Figure 2. Differences in disease specific survival (A) and disease free survival (B) for 7 th pT1- classified patients with a watchful waiting strategy of the neck which were staged using the 8th edition pT criteria. Nodal Staging Of the 173 neck dissection patients, 72 (42%) were diagnosedwith nodal metastasis. Twenty- eight (16%) of these 173 patients were restaged with the 8 th edition criteria because of ENEs (Figure 1B). No significant differences were seen in N-status restaging between anatomical locations. Twenty-six of the 28 restaged patients had been treated postoperatively with radiotherapy, which was combined with chemotherapy in one patient. The 8 th edition pN classification showed good stratification, with an 89% 5-year survival rate for the watchful waiting patients and pN3 staged patients having the shortest survival rates, although the difference in DSS between pN2 staged and pN3 staged patients was not significant (69% versus 48%, p = 0.072, Figure 3D and Table 2). Stage Grouping In total, 42 (20%) patients were restaged with the 8 th edition criteria. Differences in stage grouping per category between the 7 th and 8 th editions are shown in Figure 1C. Restaging with the 8 th edition resulted in a smaller difference in DSS between stage I and stage II: 11% versus 3% difference in the 5-year DSS between the 7 th and 8 th stage I and stage II editions respectively. After restaging with the 8 th edition criteria, the difference in DSS was larger between stage II and stage III, being 12% with the 7 th edition (85% and 73%, not significant) versus 20% with the 8 th edition (94% and 74%, p = 0.007) (Figure 3F and Table 2).