Impact of aggregate of risk factors for isolated locoregional failure in breast cancer patients treated with mastectomy without radiotherapy

The impact of aggregate of risk factors on isolated locoregional failure after mastectomy without radiotherapy was assessed.

We reviewed 1091 patients who had stage I–III unilateral breast cancer and received mastectomy between 1990 and 2002.

Median follow-up time was 67 (1–175) months. On multivariate analysis, four or more positive axillary lymph nodes (AXLN ≥4), pT4, primary tumor larger than 5 cm (T >5 cm), severe lymphatic invasion (ly2–3), and negative hormone receptor status (HR negative) were the statistically significant risk factors (hazard ratios 5.78, 2.31, 2.47, 2.99, and 3.40, respectively). The 8-year isolated locoregional failure-free rates of patients with single risk factor were 88% for AXLN ≥4, 93% for pT4, 93% for T >5 cm, 98% for ly2–3, and 97% for HR negative. Considering impact on isolated locoregional failure, AXLN ≥4 was termed the major risk factor and other factors were termed minor risk factors. The 8-year isolated locoregional failure-free rates were 98% for patients with only 0–1 minor risk factors (low-risk group), 86% for patients with the major risk factor alone or with only 2–4 minor risk factors (intermediate-risk group), 72% for patients with the major risk factor plus 1–2 minor risk factors (high-risk group), and 28% for patients with the major risk factor plus 3–4 minor risk factors (very high-risk group).

Aggregate of risk factors increased the risk of isolated locoregional failure significantly. Patients with the major risk factor plus one or more minor risk factors seemed to be candidates for postmastectomy radiotherapy.