Familial Nasopharyngeal Carcinoma 6

312 B. O’Sullivan and E. Yuin the TNM classification as a subcategory within T2(T2b rather than as T3). The rationale for this decisionis discussed elsewhere (Lee et al. 1999).The T4 category was also amended to includeextreme lateral extension to soft tissue described as theinfratemporal fossa (or what is probably most usuallytermed the masticator space today) or hypopharynx inaddition to gross intracranial extension and/or cranialnerve involvement. Bone involvement alone was alsorelegated to the T3 category in the 5th edition.Kalogera-Fountzila et al. 2006), and in pediatricpatients (Casanova et al. 2001). The consistent viewfrom these studies is that the 5th and 6th editionswere a significant improvement over the 4th edition,carrying superior distribution of cases across groups,and better discrimination between prognostic groups.The acceptance of the classification is further underlinedby the fact that the 5th edition TNM remainedessentially unchanged in the 2002 6th edition, but forsome minor rewording for clarification.24.3.2.2Modification of the Ho N-ClassificationTraditionally, in the Ho classification, the N-categorieswere distinguished by the position of palpable lymphnodes as they related to topographic landmarks in theneck, which create three echelons of levels and takesno account of lymph node size (Ho 1978b; Ho 1978a).N3 also included skin involvement together with disease,wholly or partially in the supraclavicular fossa.Different results have been reported about lymphnode descriptions and whether nodal size was independentlysignificant (Sham et al. 1990; Lee et al.1996b; Teo et al. 1996b) in NPC. To resolve this, adetailed analysis from Hong Kong on almost 5,000cases without distant metastasis formed the basis forthe task force recommendations (Lee et al. 1996b).Lymph node size (greatest diameter ≤6 vs. >6 cm),level (upper-mid vs. supraclavicular), and laterality(unilateral vs. bilateral) constituted the criteria forN-categorization in the 5th edition TNM (Lee et al.1996b). Multiplicity and fixation were not includeddue to combination of factors, including varied statisticalsignificance, absence of definition, or interrelationshipwith other parameters of lymph nodedescription (Johns et al. 1984; Lee et al. 1999).24.3.3Validation of the 5th and 6th Edition TNMA very extensive literature has now emerged on thevalue of the 5th edition (and the virtually unchanged6th edition) TNM and include evidence that it is validin both endemic regions as well as in the regionswhere the disease is less common including NorthAmerica, Australia and Europe (Cooper et al. 1998;Heng et al. 1999; Lee et al. 1999; Ozyar et al. 1999;Sakata et al. 1999; Hong et al. 2000; Chua et al. 2001;Ma et al. 2001; Au et al. 2003; Corry et al. 2004;24.4The Upcoming 7th Edition TNMThe AJCC and UICC are currently reviewing the overallTNM classification for all diseases in preparationfor the 7th edition that is anticipated for the comingyear. An important element in this process is the needto maintain relevance with current managementapproaches and to respond to the availability of newdata that may be considered in the revisions to theclassifications. This process involves collaborationbetween both organizations that is accomplished by aseries of disease specific task forces. In the area of headand neck, this process is led in a joint collaborationchaired by Dr Jatin Shah for the AJCC, and Dr BrianO’Sullivan, the original chair of the international taskforce that developed the 5th edition NPC TNM, for theUICC. A number of resources are available to the taskforces and include, especially, a structured process forintroducing changes to the TNM classification. Theelements of the TNM process include the developmentof unambiguous criteria for the information and documentationrequired to consider changes in the classification,establishment of a well-defined process forthe annual review of relevant literature, formation ofsite-specific expert panels, and the participation ofexperts from all over the world in the TNM reviewprocess (Gospodarowicz et al. 2004). In consideringthe forthcoming 7th edition, a number of areas havebeen considered by the head and neck task forces formodification of the NPC TNM classification and aresummarized below.24.4.1The Significance of ParapharyngealSpace Involvement TodayOver the period since the 5th edition, managementhas changed and perhaps most especially in the area