Drug withdrawal in women with progressive metastatic breast cancer while on aromatase inhibitor therapy

Metastatic and triple-negative breast cancer: challenges and treatment options

The major current conventional types of metastatic breast cancer (MBC) treatments include surgery, radiation, hormonal therapy, chemotherapy, or immunotherapy. Introducing biological drugs, targeted treatment and gene therapy can potentially reduce the mortality and improve the quality of life in patients with MBC. However, combination of several types of treatment is usually recommended. Triple negative breast cancer (TNBC) accounts for 10-20% of all cases of breast carcinoma and is characterized by the low expression of progesterone receptor (PR), estrogen receptor (ER), and human epidermal growth factor receptor 2 (HER2). Consequently, convenient treatments used for MBC that target these receptors are not effective for TNBC which therefore requires special treatment approaches. This review discusses the occurrence of MBC, the prognosis and predictive biomarkers of MBC, and focuses on the novel advanced tactics for treatment of MBC and TNBC. Nanotechnology-based combinatorial approach for the suppression of EGFR by siRNA and gifitinib is described.

Tamoxifen withdrawal in women with progressive metastatic breast cancer: a case series of six patients

Estrogen receptor (ER)-positive metastatic breast cancers after a period of response to tamoxifen develop resistance, and the disease progresses clinically. Domination of partial agonistic activity of tamoxifen over its antagonist activity has been implicated as one of the mechanisms for acquired tamoxifen resistance. Six patients with ER-positive, human epidermal growth factor receptor 2 (HER2)-negative metastatic breast cancer who were treated with tamoxifen withdrawal were retrospectively reviewed. Three patients were premenopausal and three were postmenopausal at the beginning of this treatment. Three patients had stage IV disease and three had recurrent breast cancers with median disease-free intervals of 153 months. The treatment lines of tamoxifen therapy were first-line in two, second-line in two, and third-line in one patient. One patient had relapsed during adjuvant tamoxifen therapy. The median duration of tamoxifen therapy was 16 months. The metastatic disease sites at the time of tamoxifen withdrawal were lymph nodes in six, bone in three, chest wall in one, lung in two, pleura in one, and liver in one patient. The median duration of tamoxifen withdrawal was 6.5 months (range 5-> 23 months). Five of six patients had clinical benefits with tamoxifen withdrawal: partial response in one, long stable disease (SD) in four, and SD in one patient. Five patients were treated with aromatase inhibitors after tamoxifen withdrawal. Two patients had metastatic lymph nodes examined by multi-gene panel testing, and both of their tumors had the AKT1 E17K somatic mutation. One patient also had a BRCA1 germline mutation. Tamoxifen withdrawal at the time of tumor progression while on treatment might be an important treatment option, especially for women with highly endocrine-responsive disease.

Optimal management of hormone receptor positive metastatic breast cancer in 2016

Hormone receptor positive tumors represent the most common form of breast cancer and account for most of the deaths from the disease. Endocrine therapy represents the main initial therapeutic strategy for these patients and has been associated with significant clinical benefits in a majority of patients. While in early stages endocrine therapy is administered as part of a curative approach once clinical metastases develop, the disease is considered incurable and the main management objectives are tumor control and quality of life. The two major clinical paradigms of always indicating endocrine therapy in the absence of visceral crises and sequencing endocrine treatments have been guiding our therapeutic approach to these patients. However, for many decades, we have delivered endocrine therapy with a 'one size fits all' approach by applying agents that interfere with hormone receptor signaling equally in every clinical patient scenario. We have been unable to incorporate the well-known biologic principle of different degrees of hormone receptor dependency in our therapeutic recommendations. Recent developments in the understanding of molecular interactions of hormone signaling with other important growth factor, metabolic and cell division pathways have opened the possibility of improving results by modulating hormone signaling and interfering with resistance mechanisms yet to be fully understood. Unfortunately, limitations in the design of trials conducted in this area have made it difficult to develop predictive biomarkers and most of the new combinations with targeted agents, even though showing improvements in clinical endpoints, have been directed to an unselected population of patients. In this review we explore some of the current and most relevant literature in the management of hormone receptor positive advance breast cancer.