Background/Aims: The optimal adjuvant chemotherapy and anti-human epidermal growth factor receptor 2 (HER2) therapy regimen following surgery for T1a/b HER2-positive breast cancer remains debatable.Methods: In this single-center retrospective analysis, we examined the postoperative treatment strategies for patients diagnosed with T1a/b node-negative HER2-positive breast cancer. Invasive breast cancer-free survival (IBCFS), invasive disease-free survival, and overall survival (OS) were compared between patients who received chemotherapy only, chemotherapy plus anti-HER2 therapy, and neither adjuvant treatment.Results: The analysis included 165 patients, with a median follow-up duration of 98.4 (25.8–238.5) months. Patients who did not receive any adjuvant therapy had a 15-year IBCFS rate of 86.9%, and those who received only chemotherapy exhibited a rate of 77.6%. Conversely, those who received both trastuzumab and chemotherapy had the highest 15-year IBCFS rate of 97.4%, although the difference between the treatment groups was not statistically significant (p = 0.492). Among patients with T1a tumors, chemotherapy plus anti-HER2 therapy showed the most favorable long-term IBCFS, with a 15-year rate of 100%, compared with 57.5% in the chemotherapy-only group and 79.8% in the no-treatment group (p = 0.363). The 15-year OS rate was 100% in both chemotherapy-containing treatment groups, compared with 90.4% in the no-treatment group (p = 0.068).Conclusions: In this retrospective cohort of patients with HER2-positive T1a/bN0 breast cancer, anti-HER2-containing adjuvant treatment was associated with numerically favorable long-term outcomes, particularly among those with T1a tumors. Given the retrospective study design and limited number of events, these findings should be interpreted cautiously.
Park et al. (Wed,) studied this question.