Background: Adjuvant chemotherapy has improved the length of disease-free survival and overall survival in node-negative breast cancer patients. It has been a common practice to select only the patients with higher rates of recurrence for adjuvant therapy. Therefore, it is essential to define the risk factors in node-negative breast cancer patients.
Materials and methods: Two hundred fifty-five patients with axillary node-negative breast cancers without adjuvant chemotherapy or hormonal therapy at Chang Gung Memorial Hospital between 1981 and 1986 were included in this study. Tissue blocks for DNA flow cytometry study was available in the tumors of 145 patients.
Results: The median follow-up period was 121 months and the percentages of patients with 10 years of disease-free survival (DFS) and overall survival (OS) were 75.1% and 82.2%, respectively. The significant poor prognostic factors for 10 years of OS were a tumor size larger than 3 cm, negative estrogen and progesterone receptor status, and having a non-diploid tumor (p value = 0.0176, 0.048 and 0.016, respectively). The patients with frozen section, high mitotic rate, and Scarff-Blood-Richardson (SBR) grade II and III tumors had a worse prognosis than the others, but this trend did not reach statistical significance. The patients with positive estrogen receptor status had a 10-year disease-free rate (DFR) of 94%, and these with tumors less than 2 cm plus SBR grade I had a 10-year DFR of 92%.
Conclusion: The node-negative breast cancer patients with a low risk of recurrence were those who had estrogen receptor positive, tumor less than 2 cm with SBR grade I, and intraductal carcinomas. Adjuvant chemotherapy would be no benefit for these patients.