The Brigham and Women's Hospital (BWH) Tumor Staging System for Cutaneous Squamous Cell Carcinoma is a clinical calculator used to stage cutaneous squamous cell carcinoma (cSCC), a type of skin cancer. This system is specifically applicable to patients diagnosed with cSCC. 

The BWH staging system provides a more detailed stratification of tumor risk compared to other staging systems, such as the American Joint Committee on Cancer (AJCC) system. It takes into account factors such as tumor diameter, depth of invasion, perineural invasion, and location, among others. 

The clinical utility of this calculator lies in its ability to predict patient outcomes, guide treatment decisions, and facilitate communication between clinicians. It helps in identifying high-risk tumors that may require more aggressive treatment and closer follow-up.

There are no specific exclusion criteria for the use of the BWH staging system. However, it may not be as useful in cases where the tumor characteristics do not align with the factors considered in this system. For instance, it may not be as effective in staging cSCC arising from unusual sites or in the context of genetic syndromes.

Brigham and Women's Hospital tumor staging for cutaneous squamous cell carcinoma

# Criteria
 # High-risk factors
A. Tumor diameter >= 2 cm (+1)
B. Poorly differentiated histologic characteristics (+1)
C. Perineural invasion (+1)
D. Tumor invasion beyond the subcutaneous fat (excluding bone invasion) (+1)
E. Bone invasion (+4)

# Conditions
- score == 0
- score == 1
- score == 2
- score == 3
- score >= 4