Practical Concerns Regarding the 7th Edition AJCC Staging Guidelines

Abstract

The 7th edition of the AJCC Cancer Staging Manual represents a dramatic shift in the way that cutaneous squamous cell carcinoma (cSCC) is staged, in that it is first attempt to incorporate evidence-based medicine into the staging guidelines for cSCC. In our opinion, the changes made to the seventh edition represent a significant improvement over previous editions and will ultimately lead to improved patient stratification, more accurate prognostic data, and a better framework to guide clinical decision making. However, there are a number of issues within the latest guidelines that require clarification or are impractical for clinical practice. The purpose of this paper is to highlight the key changes to the 6th edition staging manual as they pertain to cSCC, to point out impractical component of the 7th edition and/or aspects that require further clarification, and to make recommendations that address any current shortcomings to improve subsequent editions. Specific focus will be given to the inclusion of separate guidelines for cSCC and Merkel cell carcinoma (MCC), the incorporation of high-risk factors as modifiers of T stage, the addition of new guidelines for advanced T stage, and the changes in stratification of lymph node status. This paper is modified from a more comprehensive treatment of the staging of nonmelanoma skin cancer by Warner and Cockerell entitled “The new 7th edition American joint committee on cancer staging of cutaneous nonmelanoma skin cancer: a critical review,” in the American Journal of Clinical Dermatology (paper accepted, pending publication).

A programme of research to set priorities and reduce uncertainties for the prevention and treatment of skin disease

“…671 Although an improvement on the previous classification, it is not without criticism. [672][673][674] Alternative staging systems have been proposed in an attempt to stratify the large group of heterogeneous T2 tumours according to their prognostic features 666,673 and, although further validation work is required, could be useful tools when designing future clinical trials.…”

“…Nonetheless, it is not without criticism; it omits several variables associated with high-risk disease, such as host immunosuppression, previously treated tumours and the presence of chronic inflammation or location in burns and scars, and there is also some confusion regarding the precise lip location (hair-bearing or non-hair-bearing) as defined in the AJCC manual. 674 An alternative tumour staging system has been proposed in an attempt to offer better prognostic stratification of AJCC7 T2 tumours, in which T1 tumours have no risk factors but are upgraded to T2a in the presence of either perineural invasion or poor/undifferentiated or invasion beyond subcutaneous fat, T2b tumours have 2-3 risk factors and T3 tumours have bone invasion or have all four risk factors (> 2 cm diameter, perineural invasion, poorly differentiated and invasion beyond subcutaneous fat). 673 This proposed alternative may be useful for future studies to define high-risk tumours, although it remains to be validated.…”

The Clinicopathologic and Molecular Aspects of Non-Melanoma Skin Cancer

“…19 Both the depth of invasion and presence of perineural invasion significantly correlate with prognosis and >4mm thickness or depth of invasion of ≥Clark level IV are associated with a 2 fold increased rate of recurrence or 5-fold increase metastatic rate; similarly, perineural invasion is associated with a 5-fold increase in both the recurrence rate and metastatic rate. (10,20) Although not identified in the 7 th Edition of AJCC, other histologic features are important in prognosis and those include lymphovascular invasion and the presence of inflammatory features such as the presence of eosinophils and plasma cells. (21) cSCC in immunocompromised patients or those that arise in scars, sinus tracts or burns all demonstrate a more aggressive biologic phenotype with a greater metastatic rate of up to 40%.…”

“…(10,22,24) So not only are subsets with a worse prognosis critical to correctly stage in order to appropriately recognize an unrecognized metastatic potential, but also recurrent disease or persistent disease both portent a worse survival of 78% 5-year survival. (20,25) …”

The Evolution of Staging of Cutaneous Squamous Cell Carcinomas: A Structured Review

“…3,[11][12][13][14] The various subtypes of cSCC, from less aggressive histologies like verrucous carcinoma to more "staging" + "cutaneous" + "carcinoma" "staging" + "cutaneous" + "carcinomas" "staging" + "skin cancer" or "staging" + "squamous cell carcinoma"…”