Predictors of recurrence for patients with small (one centimeter or less) localized breast cancer (T1a,b N0 M0).

BACKGROUND: The frequency of small (< or = 1 cm) axillary lymph node negative invasive breast cancers (T1a,b N0 M0) is increasing because of wider implementation of breast cancer screening. Identification of prognostic factors for these patients has been based largely on retrospective pathology review. The authors analyzed histologic factors recorded in the original pathology reports to determine predictors of recurrence for patients with T1a,b N0 M0 breast cancer.
METHODS: Two hundred eighteen patients were studied. Potential prognostic factors including measured millimeter tumor size in three dimensions, histologic grade, nuclear grade, and presence or absence of lymphatic vessel invasion were documented prospectively in routine surgical pathology reports of a large community (nonuniversity based) hospital. Follow-up was performed annually by the tumor registry.
RESULTS: With a median follow-up of 6.9 years (range, 3-15.8 years), overall recurrence free survival was 93%. Poor nuclear grade (hazard ratio, 5.8; 95% confidence interval, 1.70-19.82; P = 0.004) and lymphatic vessel invasion (hazard ratio, 4.6; 95% confidence interval, 1.34-15.61; P = 0.01) were independent predictors of recurrence. Only 10% of patients had cancers with both poor nuclear grade and lymphatic vessel invasion and their 67% 7-year recurrence free survival (RFS) rate was significantly lower than the 92% RFS rate observed for patients with one of these two factors (P = 0.007) and the 99% RFS for patients with neither poor risk factor (P = 0.0001).
CONCLUSIONS: The combination of poor nuclear grade and lymphatic vessel invasion identifies a very small subset (10%) of patients with T1a,b N0 M0 breast cancer with a significant relapse risk that warrants consideration of adjuvant systemic therapy. However, the majority of patients with T1a,b N0 M0 breast cancer have an exceptionally good prognosis.