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| (i) The chapter entitled “Carcinoma of the Skin,” has been eliminated and two chapters have been created in its place: |
| (ii) “Merkel Cell Carcinoma”: an entirely new chapter specifically for Merkel cell carcinoma (MCC) has been designed (see Chapter 30). |
| (iii) This chapter has been renamed “Cutaneous Squamous Cell Carcinoma and Other Cutaneous Carcinomas” and is an entirely new staging system that, for the first time, reflects a multidisciplinary effort to provide a mechanism for staging nonmelanoma skin cancers according to evidence-based medicine. The title of this chapter reflects the basis of the data, which is focused on cutaneous squamous cell carcinoma (cSCC). All other nonmelanoma skin carcinomas (except Merkel cell carcinoma) are also to be staged according to the cSCC system. |
| (iv) Anatomic site of the eyelid is excluded—cSCC of the eyelid are staged by ophthalmic carcinoma of the eyelid (see Chapter 48). Cutaneous SCC of the penis, vulva, and mucosal lip are also excluded, as they are staged with chapters specific for those anatomic sites. |
| (v) The T staging has eliminated the five-centimeter-size breakpoint and invasion of extradermal structures for T4. Two centimeters continues to differentiate T1 and 2; however, a list of clinical and histologic “high-risk features” have been created that can increase the T staging, independent of tumor size. |
| (vi) Grade has been included as one of the “high-risk features” within the T category and now contributes toward the final stage grouping. Other “high-risk features” include primary anatomic site of ear or hair-bearing lip, invasion greater than two millimeters depth, Clark’s level greater than or equal to IV, or perineural invasion. |
| (vii) Advanced T stage is reserved for invasion of specific anatomic sites (maxilla, mandible, orbit, or temporal bone involvement for T3; appendicular or axial skeletal involvement or perineural invasion of the skull base for T4). |
| (viii) Nodal (N) staging has been completely revised to reflect published evidence-based data demonstrating that survival decreases with increasing nodal size and number of nodes involved. |
| (ix) Because the majority of cSCC tumors occur on the head and neck, the seventh edition staging system for cSCC and other cutaneous carcinomas was made congruent with the AJCC head and neck staging system. |
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