Analysis of Risk of Recurrence by Subtype in ≤ 1-cm Breast Tumors.

Introduction: Triple negative breast cancer (TNBC) is an aggressive subtype of breast cancer with higher recurrence rates than other breast cancer subtypes. Increasing numbers of women are being diagnosed with early-stage breast cancer because of improvements in screening mammography. TNBC is known to be highly sensitive to chemotherapy; however, the benefit of adjuvant chemotherapy among women with ≤ 1-cm, lymph node-negative TNBC is unknown.

Materials And Methods: We evaluated the recurrence rates and recurrence-free survival of 437 women diagnosed with stage T1a-T1bN0 breast cancer from 1997 to 2009 at 2 institutions, with a median follow-up time of 6.2 years. Furthermore, we examined the treatment regimens of these women and evaluated the association of adjuvant chemotherapy with recurrence-free survival.

Results: Chemotherapy was administered more often to younger women and to women with high-grade, human epidermal growth factor receptor 2-positive or TNBC. Recurrence-free survival did not differ significantly between TNBC and estrogen receptor-positive breast cancer (hazard ratio [HR], 0.33; 95% confidence interval [CI], 0.10-1.04; P = .058). After appropriate adjustments, no significant differences were detected in recurrence-free survival between the women who had received chemotherapy and those who had not among the women with TNBC (P = .132) or within any of the breast cancer subtypes (HR, 0.6; 95% CI, 0.2-1.9; P = .392).

Conclusion: Prospective trials of this subcentimeter node-negative breast cancer population are warranted to guide adjuvant chemotherapy decisions.