Introduction: Breast cancer is the second leading cause of cancer-related mortality despite the staggering improvement in cancer therapeutics. So far, published data illustrate endocrine therapy as the cornerstone treatment for patients with hormone receptor-positive metastatic breast cancer. Unfortunately, most patients eventually develop resistance to this treatment.
Methods: The purpose of this study is to evaluate the efficacy of mammalian target of rapamycin inhibition in reversing hormone resistance in the Lebanese breast cancer patients. Efficacy of the intervention according to the independent factors and notable side effects encountered were the primary points of the evaluation.
Results: In total, fifty patients received the combination of everolimus and exemestane. The mean age of the study population was 61 ± 11 years. Sensitivity to hormonal therapy before the start of the combination treatment was estimated at 64%. Response rate was 14%, and all patients were partial responders. After regular interval evaluation, the median progression-free survival was 5.2 months since the initiation of therapy. The main toxicities associated with the combination were stomatitis (22%), myalgia (22%), skin toxicity (8%), and hyperglycemia (4%), all Grades 1 and 2.
Conclusion: Everolimus has been shown to be effective in overcoming hormonal resistance in Lebanese breast cancer patients with results inferior to those reported in the BOLERO-2 population. The particular differences in molecular and pathological aspects of breast cancer in our region should stimulate the extensive research for a better understanding of the particular pattern of the disease.
Keywords: Breast cancer; everolimus; hormone resistance; stomatitis; toxicity.