Predicting recurrence in axillary-node negative breast cancer patients

SummaryThis study attempted to identify the risk groups in axillary node negative breast cancer patients using validated first-generation prognostic clinical and pathologic factors. An updated 10-year follow-up in 407 such patients treated by surgery alone at Roswell Park between 1976–1987 showed a 10-year recurrence rate (RR) of 19% (95% confidence interval ±5%). Predictors of outcome were, in order of strength: (1) Tumor size (p= 0.0006); RR at 10 years was 2% ± 4 for tumors ≤ 0.5cm, 6% ± 7 for tumors 0.6-1.0cm, 16% ± 9 for 1.1–2cm, 29% ± 12 for 2.1–5cm, and 40% ± 31 over 5cm; (2) Histologic differentiation (p = 0.017); poorly differentiated/anaplastic (P/A) tumors had a greater RR (24% ± 8) than well or moderately differentiated (W/M) tumors (13% ± 8); (3) Age (p = 0.046); patients < 35 showed a RR of 28% ± 20, pts 35–50, 22% ± 10, and pts > 50, 17% ± 7 (p = 0.046). Cox Model analysis showed tumor size (4 groups) significant at < 0.0001, histologic differentiation (2 groups) significant at < 0.0005 after allowing for size, and age (±50) significant at <0.05 after allowing for size and differentiation.Combining these variables into subgroups enables selecting groups at various risks of recurrence. Groups with low risk are: (1) patients with tumor≤1cm, W/M (0% RR), (2) patients with ductal carcinomain situ with microinvasion (0% RR), and (3) patients with tumors ≤1cm, P/A (8% RR). In a suggestive finding in this last group, those over age 50 achieved a RR of 3% ± 6, while those age 50 or less had RR 14% ± 15. With the exception of this last group, all should be considered highly curable using loco-regional therapy alone, and might be spared the risks and costs of routine systemic adjuvant therapy. Groups with high risk are: (1) patients with tumors > 2cm (RR 32% ± 12), and (2) patients with tumors 1.1–2cm, P/A (RR 21% ± 14). These should receive adjuvant therapy. Groups with intermediate risk are patients with tumor 1.1-2cm, W/M (RR 12% ± 12). In a suggestive finding, those in this group over age 50 had a RR of 11% ± 12, while those up to 50 had a RR of 17% ± 30. These patients should be considered to be prime candidates for clinical trials.Adding second generation factors such as DNA ploidy or S-phase fraction to first generation factors should provide additional information on which to base therapy decisions, particularly in the gray area of intermediate risk. Our study indicates that node-negative breast cancer patients represent a heterogeneous population in terms of risk and prognosis, and that an individualized approach to adjuvant therapy should be taken.