Paraneoplastic neurologic syndromes are a group of immune-mediated, cancer-associated disorders affecting the nervous system. While these syndromes are not understood fully, they are reportedly caused by an immune response against common antigens expressed by the cancer and nervous system. We describe the course of a patient who suffered paraneoplastic chorea before being diagnosed with breast cancer. A 70-year-old female presented with complaints of "shaking" movements of her head. History, physical exam findings, and preliminary workup ruled out the hereditary, metabolic, and infectious causes of chorea while brain computed tomography (CT) ruled out chorea due to a basal ganglia lesion. A paraneoplastic antibody panel identified N-type and P/Q-type voltage-gated (V-G) calcium channel binding antibodies. Subsequent age-appropriate cancer screening, which included a colonoscopy and screening mammograms, identified breast cancer. The patient had bilateral total mastectomies. Histopathology confirmed mixed invasive ductal and lobular carcinoma that was estrogen receptor positive, progesterone receptor positive, and human epidermal growth factor receptor 2 negative. In addition to mastectomies, the patient received adjuvant anastrozole. The appearance of choreiform movements before the diagnosis of breast cancer and the presence of paraneoplastic antibodies indicated that the chorea was most likely paraneoplastic in nature. Our patient continues to have choreiform movements despite undergoing bilateral mastectomies and receiving anastrozole, prednisone, and rituximab. We suspect the mastectomies and immune modulating therapies have not had an effect on her chorea because her P/Q and N-type V-G calcium channel binding antibodies may be intracellular. This case of paraneoplastic chorea associated with breast cancer is unusual. To the best of our knowledge, only one other case of paraneoplastic chorea associated with breast cancer has been reported in the English literature.

Clinical and cost-effectiveness evidence on fulvestrant for untreated hormone-receptor positive locally advanced or metastatic breast cancer was submitted to the single technology appraisal process of the National Institute for Health and Care Excellence by the manufacturer of fulvestrant. The Southampton Health Technology Assessments Centre was commissioned by the National Institute for Health and Care Excellence as an independent Evidence Review Group to critique the company's submitted evidence. Fulvestrant was compared directly with anastrozole in two randomised controlled trials and was compared indirectly by means of a network meta-analysis with anastrozole, letrozole and tamoxifen. This article summarises the Evidence Review Group's review of the company's submission and summarises the guidance the National Institute for Health and Care Excellence Appraisal Committee issued in January 2018. The Evidence Review Group had several concerns, the most important of which related to the degree to which fulvestrant might confer a benefit in overall survival. This was because mature data were not available from the key phase III trial FALCON. The economic model was sensitive to changes in overall survival and the Evidence Review Group considered the incremental cost-effectiveness ratio was uncertain and likely to increase once mature results from FALCON become available. The National Institute for Health and Care Excellence Appraisal Committee concluded that fulvestrant could not be recommended for treating locally advanced or metastatic estrogen-receptor-positive breast cancer in postmenopausal women who have not received previous endocrine therapy.

Fulvestrant is the first selective estrogen receptor (ER) downregulator available in clinical practice. It is a pure antiestrogen with no agonistic effects, leading to degradation of ER alpha, with activity in tamoxifen-resistant breast cancer (BC) models. Pharmacokinetic and pharmacodynamic studies and several postmarketing clinical trials led to the definition of the optimal dose at 500 mg intramuscularly on days 1, 15, and 29 and then every 28 days. Targeting ER alpha, fulvestrant is a cornerstone of treatment in luminal BCs, whose growth is largely driven by the ER pathway. In endocrine therapy-naïve patients with hormone receptor-positive, HER2- advanced BC (ABC), fulvestrant yielded significantly longer progression-free survival compared to anastrozole in the Phase III FALCON study. Due to its mechanism of action and pharmacokinetic properties, fulvestrant is an ideal backbone for combination therapies. Preclinical studies have shown synergism with drugs acting on signaling pathways involved in the development of endocrine resistance, among which the cyclin D/cyclin-dependent kinase 4-6/retinoblastoma pathway and the phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin pathway, contributing to overcoming or delaying endocrine resistance. In the Phase III PALOMA-3 trial, a combination of the cyclin-dependent kinase 4/6 inhibitor palbociclib with fulvestrant significantly improved progression-free survival over fulvestrant alone in women with hormone receptor positive, HER2- ABC progressing during prior endocrine therapy. This led to approval of the combination in this clinical setting. Similar results were obtained with abemaciclib and ribociclib. Combination with pan-PI3K inhibitors, though showing some efficacy, was hampered by the toxicity of these agents, and studies in combinations with more selective inhibitors of the α-catalytic subunit of PI3K are ongoing. Fulvestrant has shown partial activity also in patients with tumors harboring mutations of the ESR1 gene. It is thus a key drug in the treatment of ABC, whose role in combination with new targeted agents is still evolving.