Clinical Response and Safety of Letrozole-based Therapy in Postmenopausal Sudanese Women with Estrogen Receptor-positive/HER2-Negative Breast Cancer: A Retrospective Cohort Study

Abstract

Introduction: Estrogen receptor-positive/HER2-negative breast cancer is the most common molecular subtype of breast cancer. Aromatase inhibitors such as letrozole are part of the standard endocrine treatment regimen for postmenopausal patients; however, real-world evidence on patient outcomes from resource-limited African countries remains sparse. This study assessed the efficacy and safety of letrozole-based treatment regimens in postmenopausal Sudanese patients with ER-positive/HER2-negative breast cancer. Methods: A retrospective cohort study was conducted among postmenopausal women at Khartoum Oncology Teaching Hospital, Sudan, between March 2018 and March 2020. Eligible participants were postmenopausal women with ER-positive/HER2-negative breast cancer who had received letrozole-based treatment regimens. Four groups were defined: docetaxel + letrozole, docetaxel + letrozole + radiotherapy, letrozole + radiotherapy, and mastectomy + letrozole. Data were collected from medical records, and the outcomes assessed included changes in tumour size, metastasis status, relapse, radiographic findings, and adverse effects. Descriptive and inferential non-parametric statistical analyses were performed using SPSS. Statistical significance was set at p < 0.05. Results: Forty-six participants with a median age of 58.5 years (45–73) were included. Localised disease was present in 73.9% of participants, and T3 tumours accounted for 71.7%. Docetaxel + letrozole achieved complete tumour clearance in all 11 patients and produced a statistically significant reduction in tumour size (p = 0.001). Letrozole + radiotherapy reduced tumour size by 97.1% (p < 0.001), while mastectomy + letrozole resulted in complete absence of detectable tumour after surgery (p = 0.031). The metastatic multimodal group did not demonstrate statistically significant tumour control (p = 0.063). Overall, 37.0% of participants experienced relapse, predominantly among those with metastatic or T4 disease. Arthralgia was the most common adverse effect (26.1%), followed by hot flushes (23.9%). Conclusion: Letrozole-based therapy showed favourable tumour responses in postmenopausal Sudanese women with localised hormone receptor-positive/HER2-negative breast cancer, particularly when combined with docetaxel, radiotherapy, or surgery. In contrast, metastatic disease was associated with a poor response and relapse despite combination therapy. Further studies are required to confirm these findings and evaluate survival outcomes.