Stage IIA Breast Cancer (T2N0M0)
A 2.5 cm breast mass with no lymph node involvement and no distant metastases is classified as Stage IIA breast cancer. 1, 2
TNM Classification Breakdown
Primary Tumor (T) Classification
- A 2.5 cm tumor is classified as T2, defined as a tumor >20 mm but ≤50 mm in greatest dimension 1
- This falls outside the T1 category, which only includes tumors ≤20 mm 2
- The T2 designation specifically captures tumors between 2.0 cm and 5.0 cm 1
Regional Lymph Node (N) Classification
- N0 indicates no regional lymph node metastasis identified histologically or clinically 1
- This classification applies when pathological examination reveals no nodal involvement (pN0) or when clinical examination shows no suspicious nodes (cN0) 2
Distant Metastasis (M) Classification
- M0 indicates no clinical or radiographic evidence of distant metastases 1
- This designation is maintained throughout treatment unless new metastatic disease is identified 1
Overall Stage Grouping
The combination of T2N0M0 corresponds to Stage IIA disease according to the AJCC Cancer Staging Manual and ESMO guidelines 1, 2
Key Staging Distinctions
- Stage IA would require a T1 tumor (≤20 mm) with N0M0 2
- Stage IIB would require either T2N1M0 or T3N0M0 1
- The 2.5 cm size places this tumor definitively in T2 category, making it Stage IIA rather than Stage I 1, 3
Clinical Significance
- Stage IIA breast cancer represents early-stage disease with favorable prognosis when appropriately treated 1
- The absence of lymph node involvement (N0) is a critical favorable prognostic factor 1
- Tumors at exactly 2.0 cm show intermediate survival patterns between smaller (<2.0 cm) and larger (2.1-3.0 cm) tumors, with 10-year survival rates of approximately 86% 3