Outcome differences between patients with node-negative breast cancer classified according to the st. gallen risk categories

Purpose: The purpose of this study was to compare the 2007 St. Gallen risk categories with the outcomes of patients with node-negative breast cancer (NNBC). Patients and Methods: We retrospectively reviewed the medical records of 1500 women with pathologically T1-T3 NNBC treated at the Clinic Hospital, Valencia University (Spain) from 1982 to 2000. Systemic adjuvant treatment was administered to 89.9% of the patients in the whole sample (37% received only hormonal therapy and 52.9% chemotherapy). The 2007 St. Gallen criteria were used to divide the whole sample into 1201 patients with intermediate risk (with ≥ 1 of the following: pathologic tumor size > 2 cm, grade 2-3, estrogen receptor and progesterone receptor absent, HER2/neu gene overexpressed or amplified, or age < 35 years) and 299 patients with low risk. Of the 1201 patients with intermediate risk, 56% received adjuvant chemotherapy. The intermediate- and low-risk groups were compared for relapse-free survival (RFS) and breast cancer-specific survival (BCSS). Results: Median follow-up of the entire sample was 61 months (range, 2-251 months). At 5 years, the overall RFS rate was 86%, and the BCSS rate was 95%. For low-risk patients, the RFS rate was 92%, and the BCSS rate was 98%. For intermediate-risk patients, the RFS rate was 84%, and the BCSS rate was 94%. There was a statistically significant difference between the 2 groups in terms of RFS (P = .006) and BCSS (P = .041) independent of received treatment. Conclusion: Using the St. Gallen risk categories resulted in significantly different outcomes for patients with NNBC. The St. Gallen classification might be a valuable clinical tool when assessing patients with NNBC.