Clinical Information and Prognosis of High-risk Luminal Breast Cancer Subjects Eligible for the MonarhE Study.

Introduction: Luminal breast cancer is the most common breast cancer subtype. Although its prognosis can be good, this type of breast cancer is characterized by a high incidence of late recurrence. However, to the best of our knowledge, there are no publications showing prognostic value regarding the invasive-disease-free survival (IDFS) and distant relapse-free survival in this group in clinical practice. Therefore, this study examined the clinical data and prognosis of patients participating in the MonarchE trial. Methods: This study included patients who underwent surgery at Tokyo Metropolitan Komagome Hospital and whose corresponding prognosis to the Monarch E trial could be followed up. Results: The total number of participants was 152, of whom 104 (68%) were treated with chemotherapy. Seventy-five patients (49%) were postmenopausal. The IDFS after 5 years was 85.0%. Although IDFS did not differ in terms of the menstrual status, premenopausal patients tended to receive a higher proportion of tamoxifen, and there was a greater number of patients treated with chemotherapy. However, neither chemotherapy nor menstrual statuses were found to affect the IDFS incidence. Conclusions: Real clinical data applicable to the MonarchE study were examined. Our univariate analysis revealed that there were no factors affecting IDFS.