Relapse profile of early breast cancer according to immunohistochemical subtypes: guidance for patient’s follow up?

Abstract

Purpose: To analyze the profile of annual recurrence rate (ARR) of patients with early breast cancer (BC) in Tunisia. Patients and methods: We classified 293 patients with histologically confirmed early BC relapsing after 1 year of follow up into three subgroups: hormone receptor (HR)+ ‘HR’ [estrogen receptor (ER)+ or progesterone receptor (PR)+ and human epidermal growth factor receptor 2 (HER2)–], triple negative ‘TN’ (ER–, PR– and HER2 score 0/1 or fluorescence in situ hybridization (FISH)/chromogenic in situ hybridization negative) and HER2 overexpression ‘HER2’ (HER2+). ARR was restricted to follow-up contribution of each specified time interval. The HR group was the reference group for comparison. Results: A higher proportion of patients who were up to 35 years old (18% versus 10%, p = 0.04), and patients with obesity (46% versus 26%, p = 0.045) was seen in the TN group. Median time to relapse (MTR) was shorter in TN and HER2 groups than in HR patients (20 and 29 months compared with 56 months, respectively, p < 0.001). In the HR group, the ARR was 22%, 16% and 10% at 3, 4 and 5 years respectively, becoming less than 3% at 7 years. In the TN group, 71% of patients relapsed during the first 2 years and the ARR declined rapidly to less than 1.5% after 4 years. In the HER2 group, the ARR peaked at 2 years (29%) and decreased significantly to 7% and 3% at 5 and 7 years respectively. Adjuvant trastuzumab delayed the MTR from 24 to 34 months ( p = 0.022). Conclusion: The relapse risk in Tunisian patients is higher in young women and patients with HER2+ and TN tumors. A long and close follow up is recommended for patients with HR and HER2. Conversely, we suggest that follow up in patients with TN could be spaced after 4 years (ARR being <1.5% after this period).