Breast cancer with non-inflammatory skin involvement: current data on an underreported entity and its problematic...

Area of Science:

• Oncology
• Pathology
• Surgical Oncology

Background:

• Non-inflammatory skin involvement (NISI) is classified as T4b in breast cancer staging.
• This classification may not accurately reflect tumor heterogeneity and prognostic significance.
• The impact of NISI on axillary lymph node involvement (ALNI) requires further investigation.

Purpose of the Study:

• To evaluate the association between NISI and ALNI.
• To assess the appropriateness of including NISI in the T4b category.
• To propose an improved classification system for breast cancer with NISI.

Main Methods:

• Retrospective analysis of 166 breast cancer cases with NISI (TNM classification T4b).
• Tumor size and stage distribution analysis.
• Comparison of ALNI in a subgroup of 50 NISI patients with a matched control group.

Main Results:

• NISI was significantly associated with increased ALNI (HR, 2.66; 95%CI, 1.59-4.63; p<0.0001).
• Breast cancer cases with NISI exhibit high heterogeneity, violating tumor classification principles.
• Current T4b classification for NISI lacks prognostic significance.

Conclusions:

• The current TNM classification of NISI as T4b is problematic due to heterogeneity.
• Reclassifying NISI tumors by size (T1-3) and adding a prognostic descriptor (e.g., S1) is recommended.
• This proposed change would improve accuracy and prognostic value in breast cancer staging.