Aromatase inhibitors (AIs) have been considered first-line therapy for patients with hormone-dependent breast cancer due to their high efficacy and good tolerability. However, AIs are not free of adverse events, and studies show that therapy with AIs is associated with an increased risk of cardiovascular events and the development of insulin resistance and diabetes. We searched the Cochrane Central Register of Controlled Trials, PubMed and EMBASE up to 27 October 2020 for the prevalence of cardiovascular and/or metabolic adverse effects during treatment with AIs in postmenopausal women with breast cancer. A meta-analysis was performed using a random effects model. Odds ratios and 95% confidence intervals were calculated and illustrated using forest plot charts. We performed separate analyses depending on trial design. Twenty two studies met the inclusion criteria. AIs were associated with a higher risk of cardiovascular events, especially when we compared study arms in which AIs were used (alone or in sequence with TAM) with the arms in which TAM was used alone (OR = 1.16; 95%CI 1.04–1.30) or when comparing patients taking AIs alone to patients taking TAM alone or in sequence with AIs (OR = 1.24; 95%CI 1.11–1.38). A pooled analysis of five trials comparing adjuvant AIs to TAM showed the odds for arterial hypertension being 1.31 times higher for patients taking AIs; however, this did not reach statistical significance (OR = 1.31; 95%CI 0.47–3.65). We have not shown an increased risk of dyslipidemia or weight gain with the use of AIs. Our results suggest that postmenopausal women with breast cancer treated with AIs have an increased risk of cardiovascular events in comparison with TAM, potentially due more to a cardioprotective effect of the latter than the cardiotoxicity of AIs. We were unable to prove a similar association for hypertension, dyslipidemia, hyperglycemia or weight gain. Further high-quality RCTs and post-marketing safety observational studies are needed to definitively evaluate the impact of AIs on metabolic disorders in breast cancer patients.
Context: Among cancer patients receiving chemotherapy, there is a growing trend to use self-medication. Many of them take preparations sold over the counter (OTC) and dietary supplements containing plant raw materials. Aims: The aim of this study is to evaluate the herbal OTC drug and dietary supplement usage among patients treated on the chemotherapy ward. Settings and Design: An anonymous survey was conducted among 92 patients of the chemotherapy ward of the Lower Silesian Oncology Center in Wroclaw (Poland) with the approval of the Bioethical Commission of the Medical University in Wroclaw (no KB-562/2014) and The Declaration of Helsinki. Methods and Material: An anonymous survey was conducted among 92 patients of the chemotherapy ward of the Lower Silesian Oncology Center in Wroclaw (Poland) in 2015. The questions concerned the use of herbal preparations by patients during chemotherapy. Statistical analysis used: The statistical analysis was developed using programs: Microsoft Office Excel 2007 and STATISTICA 10 (StarSoft Inc.). Analysis was performed by χ2 test. Results: The study has confirmed that the use of herbal OTC products and dietary supplements among cancer patients is a common occurrence. The main source of information about herbal preparations is the Internet and the most common place of purchase is a pharmacy. Conclusions: It is necessary to educate cancer patients to increase their awareness of the importance of a doctor's knowledge about all preparations that they take. Pharmacists play a very important role in self-medication of the patients. Thus, pharmacy students' education is needed in this field as well.
Nifuroxazide (4-hydroxy-benzoic acid; 2-[(5nitro-2-furanyl)methylene]hydrazide) is a chemotherapeutic agent belonging to the nitrofuran family. Indications for its use are acute and chronic bacterial diarrhea and other diseases with diarrhea (1). The drug has local antibacterial activity against some Gram-positive bacteria of the genus Staphylococcus and Gram-negative bacteria from the Enterobacteriaceae family: Yersinia spp., Escherichia spp., Enterobacter spp., Klebsiella spp. and Salmonella spp. It does not affect the bacteria Proteus vulgaris, Proteus mirabilis and Pseudomonas aeruginosa (1-3). Recently, attention has been paid to its antitumor potential in neuroblastoma, multiple myeloma, colorectal and breast cancer, efficacy in the treatment of graft-versus-host disease and nephroprotection in diabetes (4-10). The exact mechanism of action of nifuroxazide has not yet been identified. It probably has an inhibitory effect on dehydrogenase activity and protein synthesis in bacterial cells. Aldehyde dehydrogenase (ALDH) is responsible for the bioactivation of this prodrug. It has been found that nifuroxazide is a potent inhibitor of the Janus kinase 2 pathways and transcription factor 3 (JAK2/STAT3). It also has direct effects on oxidative stress and apoptosis (2, 4-6). Frequent self-administration of this drug by patients makes it necessary to pay attention to selfmedication, which in accordance with the guidelines of the World Health Organization is defined as ìusing medication by the consumer to treat signs/symptoms or minor health problems, recognized as such by themselvesî. In practice, this term also includes treatment by family members or friends, mainly, when the child is being treated (11). It should be responsible and safe, especially considering that diarrhea, in particular, acute diarrhea, is a serious problem of primary and hospital care. Itís serious complications, such as electrolyte disturbances, oligovolemic shock and even death, are dangerous especially for newborns, babies, small children and elderly people, due to their susceptibility to dehydration (12, 13). The fact that adverse effects inevitably accompany the desired therapeutic effects
Introduction. Breast cancer is the most common cancer occurring in women and causing the highest number of deaths among them. The role of xenoestrogens has been the subject of many studies in the pathogenesis of breast cancer. Less is known about the impact of xenoestrogens on the effectiveness of hormone therapy used to treat breast cancer, and thus possible drug-xenostrogen interactions. Objective. The aim of this review is to summarize the current state of knowledge and present perspectives for further research on the impact of xenoestrogens on the effectiveness of drugs used in the treatment of hormone-dependent breast cancer. Current state of knowledge. Phytoestrogens, in particular flavonoid genistein, are the best studied group of xenoestrogens in terms of interaction with drugs used in the treatment of breast cancer, due to their frequent use, including their use in alleviating the adverse effects of hormone therapy. Analyzing the current state of knowledge, it seems that phytoestrogens intake should be avoided during conventional anti-cancer treatment. Of the other xenoestrogens, bisphenol A (BPA) is one of the best-tested compounds for interactions with drugs used to treat breast cancer. It has been shown that bisphenol A could reduced therapeutic effect of active tamoxifen metabolite and cytostatics used in breast cancer treatment. Conclusion. Confirmation in clinical trials of the results obtained in vitro and in vivo tests, would enable the creation of specific recommendations for patients undergoing breast cancer treatment, especially hormone therapy. An area requiring further research is the analysis of the effects of xenoestrogens other than phytoestrogens, e.g. metalloestrogens, on the effects of drugs used in the treatment of breast cancer.
Endocrine-disrupting compounds (EDC) play an important role in the increased incidence of breast cancer (BC). There are some 160 xenoestrogens that may be involved in the development of BC. Much less is known about the influence of xenoestrogens on the effectiveness of the treatment of BC. The aim of this study was to analyze the interaction of metalloestrogens (aluminum and chromium (III)) and drugs used in the treatment of hormone-dependent BC—aromatase inhibitors (AI)—letrozole and exemestane. A cell viability assay, a flow cytometer analysis of apoptosis and cell cycle phases, and protein activity of BAX and Bcl-2 were performed on two human breast cancer cell lines—MCF-7 and MCF-7/DOX. In MCF-7 cells, the lower concentration of exemestane and higher of letrozole, in combination with metalloestrogens, results in a decrease in the effectiveness of drugs. Additionally, in the MCF-7/DOX cell line, we observed that the combination of metalloestrogens and AI leads to a decrease in the drug’s effectiveness due to an increase in the viability of breast cancer cells (both concentrations of letrozole and higher concentration of exemestane). In both cell lines, the reduction in the effectiveness of AI, in combination with metalloestrogens, is not related to the influence on the cell cycle. Our results confirm that exposure to metalloestrogens may negatively affect the effectiveness of hormone therapy with AI. Further studies are needed to fully explain the mechanism of these interactions.
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