Causal Therapy of Breast Cancer Irrelevant of Age, Tumor Stage and 
ER-Status: Stimulation of Estrogen Signaling Coupled With Breast 
Conserving Surgery

ABSTRACT: BACKGROUND: Results of long-term studies justify that the rate of breast cancer recurrence and tumor-related mortality remains quite unpredictable, regardless of the use of any current therapeutic measures. OBJECTIVE: Since the application of standard therapies, such as surgery, radiation, chemotherapy and antiestrogen administration does not work as might be expected; our therapeutic practice requires thorough rethinking. METHOD: Published long-term therapeutic results on breast cancer cases were analyzed in correlation with stage at diagnosis, ER-status of tumors and patients’ age. The effectiveness of current therapeutic measures was also compared by estimating the rate of tumor-free survival, breast cancer recurrence and breast cancer-specific mortality. RESULTS: Diagnosis and treatment of breast cancer at an early stage cannot improve the rate of tumor-free survival. Poor differentiation of tumors, ER-negativity in particular, defines poor prognosis even after applying aggressive therapies. In patients treated with in situ breast cancer, the recurrence-rate of invasive tumor increased directly with ageing irrespective of tumor size or ER-status at diagnosis. Women who underwent lumpectomy without adjuvant radiation or chemotherapy exhibited significantly better overall and breast cancer specific survival rates than those receiving mastectomy, regardless of stage and ER-status of tumors. Antiestrogen treatment exhibited unforeseeable effectiveness even on targeted ER-positive tumors. Recent patents propose the detection of ESR1-gene amplification or restoration of ER-alpha expression for prediction of effective antiestrogen treatment, suggesting a crucial inhibitory role of estrogen-signaling against tumor-growth. CONCLUSION: Estradiol-induced upregulation of estrogen signaling coupled with sparing of the estrogen-rich mammary fatpad are the most effective strategies against breast cancer.