National Comprehensive Cancer Network (NCCN) guidelines, this updated AJCC staging system does not take into account host factors such as immunosuppression and tumor recurrence, which many believe correspond to increased risk of metastasis.7 A study in 2012 compared the 2 systems and found that neither was reliable in predicting the estimated risk of metastasis.10 In 2013, an alternative system, now known as the Brigham and Women’s Hospital (BWH) tumor staging system, further attempted to stratify T2 stage tumors by subdividing this group into T2a and T2b based on specific defined high-risk factors found to correlate with outcome.6,7,9 These 4 risk factors include tumor diameter less than equal to 2 cm, poorly differentiated histologic characteristics, perineural invasion greater than 0.1 mm, and tumor invasion beyond subcutaneous fat (excluding invasion of bone, which automatically upgrades a tumor to stage T3) (Table 1).9 T1 and T2a are generally considered low stage, whereas T2b and T3 are high-stage tumors. While further validating studies are needed, a multivariate analysis by Karia and colleagues compared the AJCC, UICC (International Union Against Cancer), and BWH staging systems. This study revealed superiority in the BWH staging system in terms of dividing patients with good prognosis (97% 10-year cure rate) into the 2 lower stages (BWH T1 and T2a), while appropriately upstaging the tumors with poor outcomes into the higher-risk stages (T2b andT3).6
