Objectives There has been conflicting data on the prognostic value of adjuvant chemotherapy-induced amenorrhea (ACIA) in breast cancer (BC) patients. The aim of our study was to assess prognosis value of ACIA in Tunisian premenopausal patients with luminal BC

Methods We conducted a retrospective study including premenopausalpatients with localized luminal BC treated in the oncology department of the military hospital of Tunis between January 2013 and December 2019. ACIA was defined as absence of menses for at least 6 months occurring during CT or within 3 months from the end of CT

Results 83 patients were included. Median age was 40 years. ACIA occurred in 60% of patients: 70% had luminal A and 30% had luminal B BC. Patients with higher BMI were more likely to develop ACIA (p=0.10).Median follow up was 67 months. Hazard Ratio for Disease-Free Survival (DFS) suggested that ACIA was associated with significant reduction in the risk of recurrence (HR=0.1, p<0,001). ACIA was also associated to prolonged Overall Survival (OS)(HR=0.32, p=0.032). OS and DFS benefit because of ACIA was associated with positive lymph nodes (LN) (HR=0.1, p=0.003 for OS) and (HR = 0.22, p<0.001 for DFS).LN involvement (p=0.043), tumor size ≥ 4cm (p=0.03) and ki67 ≥30% (p=0.08) were associated with lower DFS. ki67 ≥30% (p=0.023) and tumor size ≥ 5cm (p=0.052)were associated with lower OS

Conclusions ACIA in luminal BC was significantly correlated to better OS and DFS supporting the theory of indirect endocrine effect of CT in addition to its cytotoxic effect.