(HealthDay News) — For patients with human epidermal growth factor receptor 2-positive (HER2+) breast cancer, distant invasive recurrence is low for T1a tumors and is higher for T1b tumors, especially those with T1b tumors reported at 1.0 cm, according to a study published online June 2 in the Journal of Clinical Oncology.

Lou Fehrenbacher, MD, from Kaiser Permanente in Northern California, and colleagues investigated the risk of invasive recurrence among 234 patients with small, node-negative HER2+ breast cancer. Participants with T1a+bN0M0 tumors, identified from a large, integrated health care system, had a median follow-up of 5.8 years.

The researchers identified 15 invasive recurrences, of which 47% were local/regional only. The 5-year distant invasive relapse-free interval (RFI) was 98.2% among 171 T1ab patients not treated with adjuvant trastuzumab or chemotherapy; 99.0% for T1a patients; and 97.0% for T1b patients. For T1a, T1b, and T1b tumors reported at 1.0 cm, the local/regional plus distant 5-year invasive RFI was 97.0%, 91.9%, and 89.4%, respectively. 

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About one-quarter (24%) of the T1ab cohort comprised T1b tumors reported at 1.0 cm, which accounted for 61% of the cohort total tumor volume and three-quarters of distant recurrences (75%). The invasive RFI was lower for T1b 1.0 cm tumors (84.5%) than for T1a tumors (97.4%; P = 0.009).

“Potential risk differences for T1a and T1b, including the 1.0 cm tumors, should be considered when making treatment decisions,” the researchers wrote.


  1. Fehrenbacher L, Capra AM, Quesenberry CP et al. Distant Invasive Breast Cancer Recurrence Risk in Human Epidermal Growth Factor Receptor 2–Positive T1a and T1b Node-Negative Localized Breast Cancer Diagnosed From 2000 to 2006: A Cohort From an Integrated Health Care Delivery System. J Clin Oncol. 2014;doi:10.1200/JCO.2013.52.0858.