Table 4

BWH T staging system for CSCC (adapted from Ruiz et al108)

T stagePrimary tumor (T)
T10 high-risk factors*
T2a1 high-risk factor*
T2b2–3 high-risk factors*
T34 high-risk factors or bone invasion*
  • *BWH high-risk factors include tumor diameter ≥2 cm, poorly differentiated histology, perineural invasion of nerve(s) ≥0.1 mm in caliber, or tumor invasion beyond subcutaneous fat (excluding bone invasion, which upgrades tumor to BWH stage T3).

  • BWH, Brigham and Women’s Hospital; CSCC, cutaneous squamous cell carcinoma.