Impact of postdiagnostic statin use on ovarian cancer mortality: A systematic review and meta-analysis of observational studies

Drug Repositioning for Ovarian Cancer Treatment: An Update

Ovarian cancer (OC) is one of the most prevalent malignancies in female reproductive organs, and its 5-year survival is below 45%. Despite the advances in surgical and chemotherapeutic options, OC treatment is still a challenge, and new anticancer agents are urgently needed. Drug repositioning has gained significant attention in drug discovery, representing a smart way to identify new clinical applications for drugs whose human safety and pharmacokinetics have already been established, with great time and cost savings in pharmaceutical development endeavors. This review offers an update on the most promising drugs repurposable for OC treatment and/or prevention.

Enhancing Immunotherapy in Ovarian Cancer: The Emerging Role of Metformin and Statins

Ovarian cancer metastization is accompanied by the development of malignant ascites, which are associated with poor prognosis. The acellular fraction of this ascitic fluid contains tumor-promoting soluble factors, bioactive lipids, cytokines, and extracellular vesicles, all of which communicate with the tumor cells within this peritoneal fluid. Metabolomic profiling of ovarian cancer ascites has revealed significant differences in the pathways of fatty acids, cholesterol, glucose, and insulin. The proteins involved in these pathways promote tumor growth, resistance to chemotherapy, and immune evasion. Unveiling the key role of this liquid tumor microenvironment is crucial for discovering more efficient treatment options. This review focuses on the cholesterol and insulin pathways in ovarian cancer, identifying statins and metformin as viable treatment options when combined with standard chemotherapy. These findings are supported by clinical trials showing improved overall survival with these combinations. Additionally, statins and metformin are associated with the reversal of T-cell exhaustion, positioning these drugs as potential combinatory strategies to improve immunotherapy outcomes in ovarian cancer patients.

Advances in ovarian cancer treatment using a combination of statins with other drugs

New anti-cancer drugs are constantly being developed, especially targeted drugs. Although these drugs have achieved significant clinical efficacy, they do not play a significant role in ovarian cancer. Moreover, the research cycle and costs of such drugs are often huge. The repositioning of conventional drugs has gradually become a concern. Statins, as traditional lipid-lowering drugs, play a role mainly by inhibiting HMGCR. In recent years, epidemiological studies and in vitro experiments have confirmed its anti-cancer effect, especially the effect of anti-ovarian cancer. The mutation rate of TP53 in ovarian cancer is as high as 95%, while HMGCR is often highly expressed in TP53 mutant tumors. However, the effect of prospective clinical trials is not ideal. This result seems understandable considering that it seems unrealistic for a lipid-lowering drug to completely inhibit tumor growth. Therefore, statins play more synergistic roles in the treatment of ovarian cancer. Because ovarian cancer is a highly heterogeneous tumor, it may be a good choice to deeply understand the mechanism of statins in the treatment of ovarian cancer and achieve precise treatment by combining it with other drugs.

Statin use improves the prognosis of ovarian cancer: An updated and comprehensive meta-analysis

Statins are lipid-lowering agents that have also been found to have anticancer effects. The relationship between statin use and clinical outcomes in ovarian cancer (OC) remains controversial, as previous assessments of the relationship between statin use and OC prognosis have yielded inconsistent results. Therefore, a comprehensive meta-analysis was performed in the present study to investigate this association. Studies were systematically retrieved by searching the PubMed, Embase and Cochrane Library databases, and consulting reference lists of the related studies. The search timeframe was from database creation to September 1, 2022. Pooled hazard ratios (HRs) with corresponding 95% confidence intervals (CIs) were calculated to assess the association. In the present meta-analysis, 16 studies with 37,660 patients with OC were included, of which 11,296 patients had been prescribed statins. The results showed that statin use markedly improved the overall survival time (OS; HR, 0.79; 95% CI, 0.73-0.85; P<0.00001) and OC-specific survival time (HR, 0.84; 95% CI, 0.80-0.89; P<0.00001), especially the OS time in patients with serous OC (HR, 0.81; 95% CI, 0.74-0.89; P<0.0001) and endometrioid OC (HR, 0.80; 95% CI, 0.66-0.98; P=0.03). In addition, survival rate was higher in patients who used statins after OC diagnosis (HR, 0.79; 95% CI, 0.73-0.85; P<0.00001). However, there was no statistically significant association between statin use and the prognosis of mucinous and clear cell OC. The results suggested that statin use markedly improved the OS in patients with OC, including in those with serous and endometrioid OC. Statins were also found to improve the prognosis of patients of both Asian and non-Asian ethnicities. In addition, both lipophilic and hydrophilic statins improved the survival in patients with OC, especially in patients using statins after OC diagnosis. However, the effect may vary depending on the statin type, duration of use and cancer type, and more well-designed studies are needed to further evaluate this.

Statins as Repurposed Drugs in Gynecological Cancer: A Review

Discovering new drugs is an expensive and time-consuming process, including target identification, bioavailability, pharmacokinetic (PK) tests, pharmacodynamic (PD) tests, toxicity profiles, recommended dosage test, and observation of the side effects, etc. Repurposed drugs could bypass some steps, starting from phase II trials, and shorten the processes. Statins, also known as HMG-CoA inhibitors (HMGCR), are commonly used to manage and prevent various cardiovascular diseases and have been shown to improve the morbidity and mortality of patients. In addition to the inhibitory effects on the production of cholesterol, the beneficial effects of statins on the prognosis and risk of various cancers are also shown. Statins not only inhibited cell proliferation, metastasis, and chemoresistance but affected the tumor microenvironment (TME). Thus, statins have great potential to be repurposed in oncology. Hence, we review the meta-analysis, cohort, and case-control studies of statins in gynecological cancers, and elucidate how statins regulate cell proliferation, apoptosis, tumor growth, and metastasis. Although the results in gynecological cancers remain controversial and the effects of different statins in different histotypes of gynecological cancers and TME are needed to elucidate further, statins are excellent candidates and worthy of being repurposed drugs in treating gynecological cancers.

Drug repurposing-an emerging strategy in cancer therapeutics

Cancer is a complex disease affecting millions of people around the world. Despite advances in surgical and radiation therapy, chemotherapy continues to be an important therapeutic option for the treatment of cancer. The current treatment is expensive and has several side effects. Also, over time, cancer cells develop resistance to chemotherapy, due to which there is a demand for new drugs. Drug repurposing is a novel approach that focuses on finding new applications for the old clinically approved drugs. Current advances in the high-dimensional multiomics landscape, especially proteomics, genomics, and computational omics-data analysis, have facilitated drug repurposing. The drug repurposing approach provides cheaper, effective, and safe drugs with fewer side effects and fastens the process of drug development. The review further delineates each repurposed drug's original indication and mechanism of action in cancer. Along with this, the article also provides insight upon artificial intelligence and its application in drug repurposing. Clinical trials are vital for determining medication safety and effectiveness, and hence the clinical studies for each repurposed medicine in cancer, including their stages, status, and National Clinical Trial (NCT) identification, are reported in this review article. Various emerging evidences imply that repurposing drugs is critical for the faster and more affordable discovery of anti-cancerous drugs, and the advent of artificial intelligence-based computational tools can accelerate the translational cancer-targeting pipeline.

Effect of statins on risk and mortality of urologic malignancies: Protocol of an umbrella review

Introduction

Urologic malignancies are the major causes of morbidity and mortality in men over 40 years old, accounting for more than 20% of all malignant tumors. Several meta-analyses are shown that statin exposure can reduce the morbidity and mortality of various urologic cancers. The adjuvant roles of statin in tumor prevention and anti-tumor activity are now being gradually recognized and have gained attention. Nevertheless, to date, multiple clinical studies and meta-analyses found inconsistent results of their anti-cancer effects. This study aims to evaluate the credibility of the published systematic reviews and meta-analyses that assessed the effects of statin exposure for the incidence and mortality of urologic cancers through an umbrella review.

Methods and analysis

The guidance of overviews of systematic reviews reported in the Cochrane Handbook for Systematic Reviews of interventions will be followed while performing and reporting this umbrella review. This project was registered in PROSPERO with the registration number of CRD42020208854. PubMed, Embase and Cochrane Library will be searched for systematic reviews to identify and appraise systematic reviews or meta-analyses of interventional and observational studies examining statin use and the risks of urologic cancer incidence and mortality without language restriction. The search will be carried out on 10 February 2022. Systematic reviews based on qualitative, quantitative or mixed-methods studies will be involved and critically evaluated by two authors using the Assessment of Multiple Systematic Reviews 2 (AMSTAR2, an updated version of AMSTAR) tool. We will determine the level of evidence using the GRADE (Grading of Recommendations, Assessment, Development, and Evaluations) tool. The summary effect estimates will be calculated using random-effects models. Between- study heterogeneity will be assessed using the I² statistic. Furthermore, we will also assess the evidence of excess significance bias and evidence of small study effects.

Ethics and dissemination

Ethics approval is not required as we will search and gather data based on the published systematic reviews and meta-analyses. We plan to publish the results of this umbrella review in a peer-reviewed journal and will be presented at a urological disease conference. All the relevant additional data will also be uploaded to the online open access databases.

PROSPERO registration number

CRD42020208854.

Metformin Use and Mortality in Women with Ovarian Cancer: An Updated Meta-Analysis

BACKGROUND

Previous observational studies and meta-analysis suggested a possible association between metformin use and reduced mortality in women with ovarian cancer (OC). However, clinical factors that may influence the relationship remain poorly evaluated. We performed an updated meta-analysis to systematically evaluate the above association and to observe the potential influences of study characteristics on the association.

METHODS

Relevant studies reporting the association between metformin use and mortality in women with OC in the multivariate adjusted model were identified by search of electronic databases that included PubMed, Embase, and Web of Science. The random-effects model was adopted to combine the results.

RESULTS

Nine studies including 10030 women with OC were included. Overall, metformin use was independently associated with reduced overall mortality (hazard ratio (HR): 0.72, 95% confidence interval (CI): 0.55-0.93, P=0.01; I ² = 62%). Consistent results were observed for studies comparing metformin users with nondiabetic women and studies comparing metformin users with diabetic women who did not use metformin (P for subgroup analysis = 0.70). Further subgroup analyses showed consistent results in studies with metformin use before or after the diagnosis of OC, with or without adjustment of body mass index (BMI) and with or without adjustment of concurrent medications (P for subgroup analyses all >0.10).

CONCLUSION

Metformin use is associated with reduced mortality in women with OC, which may be independent of the diabetic status of the controls, timing of metformin use, or adjustment of BMI and concurrent medications. Clinical trials are needed to validate the potential benefits of metformin on survival of OC.

Association between statin use and the risk, prognosis of gynecologic cancer: A meta-analysis

BACKGROUND

Recent evidence has demonstrated that the salutary effect of statins on the prevention and prognosis of cancers, including gynecologic cancers. However, due to the heterogeneity of tumors, the results from related studies regarding the association between statin therapy and gynecologic cancers are conflicting. Thus, we conducted this meta-analysis to better understand the relationship between statins use and gynecologic cancers.

METHODS

We searched for articles published before July 2021 in the databases: PubMed, Web of Science, Medline, EMBASE and Google Scholar. We computed odds ratio (OR)/relative risk (RR) or hazard ratio (HR) and 95% confidence intervals (CI) regarding the association between statin use and the risk or prognosis of gynecologic cancers by using STATA 12.0 software.

RESULTS

The present meta-analysis showed that statin use was associated with a lower risk of gynecologic cancer (OR/RR = 0.89, 95% CI 0.83 to 0.96, I² = 60.6%, p < 0.001). Statin use was associated with lower risks of endometrial cancer and ovarian cancer (endometrial cancer: OR/RR = 0.81, 95% CI 0.70 to 0.94, I² = 62.3%, p = 0.001; ovarian cancer: OR/RR = 0.92, 95% CI 0.85 to 1.00, I² = 42.1%, p = 0.077). The present meta-analysis showed that statin use was associated with a lower mortality of gynecologic cancer (HR = 0.73, 95% CI 0.67 to 0.80, I² = 39.0%, p = 0.03). Statin use was associated with lower mortalities of endometrial cancer and ovarian cancer (endometrial cancer: HR = 0.71, 95% CI 0.64 to 0.80, I² = 31.9%, p = 0.144; ovarian cancer: HR = 0.78, 95% CI 0.73 to 0.83, I² = 43.9%, p = 0.051).

CONCLUSION

Statins use was inversely associated with the risk and mortality of gynecologic cancers. Meanwhile, we need more well-designed and high-quality studies with strong evidence for definite conclusions that determine clinical practice.

Statin use and incidence and mortality of breast and gynecology cancer: A cohort study using the National Health Insurance claims database

Previous studies have reported inconsistent findings concerning the impact of statin use on cancer prevention. This study examined the association between statin use and cancer incidence and mortality related to breast and gynecologic cancers in South Korea. A population-based cohort study was conducted using the National Health Insurance claims database. Women aged 45-70 years old who had taken statins for at least 6 months were compared to statin non-users of the same age from January 2005 to June 2013. The primary outcomes were cancer incidence and mortality related to breast cancer, total gynecologic cancers, cervix uteri cancer, and ovarian cancer. Cox proportional hazards regression was conducted to calculate the adjusted hazard ratios (aHRs) and 95% confidence intervals (95% CIs). Out of 587 705 women, there were 3591 cases of breast cancer, 2239 cases of gynecologic cancers, and 565 breast and total gynecologic cancer deaths during 7.6 person-years. The aHRs for the association between the risk of each cancer and statin use were 0.88 (95% CI 0.79-0.97) for breast cancer and 0.83 (95% CI 0.67-0.99) for cervix uteri cancer. Statin use was associated with decreased breast cancer mortality (HR = 0.65, 95% CI 0.43-0.99) and total gynecologic cancer mortality (HR = 0.70, 95% CI 0.50-0.98). A dose-response relationship was only found for all-cancer mortality. Statin use for at least 6 months was significantly associated with a lower risk of breast and cervix uteri cancer incidence, and with lower mortality of breast and gynecologic cancers. Further research on these associations will be needed. This article is protected by copyright. All rights reserved.

Post-Diagnostic Statin Use Reduces Mortality in South Korean Patients with Dyslipidemia and Gastrointestinal Cancer

Background: Statins play a role in lowering serum cholesterol and are known to have pleiotropic effects in a variety of diseases, including cancer. Despite the beneficial effects of statins in dyslipidemia patients, the treatment rate for dyslipidemia in Korea remains low, and evidence supporting the continued use of statins is lacking. The purpose of this study was to evaluate the effect of continued statin use and dosage on patient mortality after diagnosis of dyslipidemia and gastrointestinal (GI) cancer. Methods: We used data from the National Health Insurance Sampling (NHIS) cohort to evaluate patients diagnosed with dyslipidemia from 2002 to 2015. A total of 901 GI cancer patients with dyslipidemia and 62,727 non-cancer dyslipidemia patients were included in the study. During the study period, each patient’s medication possession ratio (MPR) after diagnosis was evaluated as a measure of continued statin use. Statin dosage was measured based on a defined daily dose (DDD). Finally, we used Cox-proportional hazard ratios to identify associations between the continual use of statins and mortality in patients with dyslipidemia and GI cancer. Results: In our study, mortality decreased with increasing MPR and reached significance in MPRs exceeding 50% for GI cancer patients and 75% for dyslipidemia patients compared to patients that did not use statins. Moreover, patients with high MPRs had significantly reduced 5-year mortality compared to non-users, and cause-specific mortality analyses revealed that high MPR was associated with decreased colorectal cancer death. We did not find a significant dose–response relationship between statins and mortality. Conclusion: Our findings suggest that continued statin use after diagnosis is associated with reduced patient mortality. Altogether, these results support the continued use of statins in dyslipidemia patients with and without GI cancer and highlight the importance of patient education by healthcare providers.

LDL, HDL and endocrine-related cancer: From pathogenic mechanisms to therapies

Cholesterol is essential for a variety of functions in endocrine-related cells, including hormone and steroid production. We have reviewed the progress to date in research on the role of the main cholesterol-containing lipoproteins; low-density lipoprotein (LDL) and high-density lipoprotein (HDL), and their impact on intracellular cholesterol homeostasis and carcinogenic pathways in endocrine-related cancers. Neither LDL-cholesterol (LDL-C) nor HDL-cholesterol (HDL-C) was consistently associated with endocrine-related cancer risk. However, preclinical studies showed that LDL receptor plays a critical role in endocrine-related tumor cells, mainly by enhancing circulating LDL-C uptake and modulating tumorigenic signaling pathways. Although scavenger receptor type BI-mediated uptake of HDL could enhance cell proliferation in breast, prostate, and ovarian cancer, these effects may be counteracted by the antioxidant and anti-inflammatory properties of HDL. Moreover, 27-hydroxycholesterol a metabolite of cholesterol promotes tumorigenic processes in breast and epithelial thyroid cancer. Furthermore, statins have been reported to reduce the incidence of breast, prostate, pancreatic, and ovarian cancer in large clinical trials, in part because of their ability to lower cholesterol synthesis. Overall, cholesterol homeostasis deregulation in endocrine-related cancers offers new therapeutic opportunities, but more mechanistic studies are needed to translate the preclinical findings into clinical therapies.

Do statins play any role in reducing the incidence and mortality of ovarian cancer? A systematic review and meta-analysis

Introduction

This systematic review and meta-analysis aimed to investigate the relationship between statin consumption and risk of incidence of ovarian cancer (OC) and associated mortality.

Methods

Computerized searches were conducted in three electronic databases (PubMed, Web of Science, and Scopus). Two calibrated authors performed the publications selection, data extraction, and quality assessment of the selected publications. The quality of the included articles was evaluated using the Newcastle-Ottawa Scale (NOS) for observational studies, and Jadad criteria for randomized clinical trials (RCTs). The electronic searches retrieved 2272 titles/abstracts. After the deletion of duplicate publications, 2030 titles/abstracts were assessed. Eighteen articles were included.

Results

Meta-analysis demonstrated that risk ratio (RR) of the association between statin consumption and OC incidence was 0.88 (95% CI = 0.75-1.03, P = 0.109). Patients receiving statin were less likely to die than those who did not receive statin, with a statistically significant association [RR = 0.76 (95% CI 0.67-0.86, P = 0.0001)]. There was no evidence of publication bias in examining the association between statin consumption and the risk of incidence and mortality from OC.

Conclusions

This study determined that statin use reduced the incidence risk of OC and significantly increased the survival in OC patients.

Recycling the Purpose of Old Drugs to Treat Ovarian Cancer

The main challenge in ovarian cancer treatment is the management of recurrences. Facing this scenario, therapy selection is based on multiple factors to define the best treatment sequence. Target therapies, such as bevacizumab and polymerase (PARP) inhibitors, improved patient survival. However, despite their achievements, ovarian cancer survival remains poor; these therapeutic options are highly costly and can be associated with potential side effects. Recently, it has been shown that the combination of repurposed, conventional, chemotherapeutic drugs could be an alternative, presenting good patient outcomes with few side effects and low costs for healthcare institutions. The main aim of this review is to strengthen the importance of repurposed drugs as therapeutic alternatives, and to propose an in vitro model to assess the therapeutic value. Herein, we compiled the current knowledge on the most promising non-oncological drugs for ovarian cancer treatment, focusing on statins, metformin, bisphosphonates, ivermectin, itraconazole, and ritonavir. We discuss the primary drug use, anticancer mechanisms, and applicability in ovarian cancer. Finally, we propose the use of these therapies to perform drug efficacy tests in ovarian cancer ex vivo cultures. This personalized testing approach could be crucial to validate the existing evidences supporting the use of repurposed drugs for ovarian cancer treatment.

Statins in risk-reduction and treatment of cancer

Statins, which are competitive inhibitors of 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase, reduce cholesterol blood levels and the risk of developing cardiovascular diseases and their related complications. In addition to this main activity, statins show pleiotropic effects such as antioxidant, anti-inflammatory and antiproliferative properties, with applications in many pathologies. Based on their antiproliferative properties, in vitro and in vivo studies have investigated their effects on various types of cancer (i.e., breast cancer, prostate cancer, colorectal cancer, ovarian cancer, lung cancer) with different genetic and molecular characteristics. Many positive results were obtained, but they were highly dependent on the physiochemical properties of the statins, their dose and treatment period. Combined therapies of statins and cytotoxic drugs have also been tested, and synergistic or additive effects were observed. Moreover, observational studies performed on patients who used statins for different pathologies, revealed that statins reduced the risk of developing various cancers, and improved the outcomes for cancer patients. Currently, there are many ongoing clinical trials aimed at exploring the potential of statins to lower the mortality and the disease-recurrence risk. All these results are the foundation of new treatment directions in cancer therapy.

Palliative treatment for bowel obstruction in ovarian cancer: a meta-analysis

OBJECTIVE

To comprehensively evaluate and compare outcomes of surgical versus nonsurgical palliative interventions for bowel obstruction due to ovarian cancer.

METHODS

Studies were obtained from database search systems of Pubmed, Medline, Wiley, Springerlink, Kluwer, Web of science and Science direct. Data were analyzed by the meta-analysis method and the random-effect or fixed-effect model. The heterogeneity between the studies was evaluated by I² index and the data were analyzed using STATA version 14.1.

RESULTS

12 studies involving 2778 cases of bowel obstruction in ovarian cancer were included, including 1225 cases of surgery and 1553 cases of palliative nonsurgical treatment. Surgery group had significantly higher remission rate of bowel obstruction (OR = 0.350, 95% CI 0.067-1.819, P = 0.000),but had no manifesting difference in the recurrence rate compared no-surgery group (RR = 0.88, 95% CI 0.76-1.03, P = 0.106). In 30-day mortality rate, surgery group had higher mortality rate (RR = 0.453, 95% CI 0.161-1.272, P = 0.000). But, surgical treatment can markedly prolong survival period (HR = 0.333, 95% CI 0.275-0.390, P = 0.000) compared nonsurgical treatment.

CONCLUSIONS

Surgery can significantly relieve the symptom of intestinal obstruction, prolonging the survival period, but had no impact on the recurrence. Compared with no-surgery group, surgery group suffered higher 30-day mortality.

Rates of underuse of statins among cancer survivors versus controls: NHANES 2011-2016

PURPOSE

Cardiovascular disease (CVD) is a major non-cancer cause of mortality among cancer survivors, and statin therapy is the mainstay of cardiovascular risk management. However, little is known about adherence to statin therapy relative to current guidelines for the management of cholesterol among cancer survivors. We investigated the prevalence of statin-eligible but untreated individuals among cancer survivors and factors associated with underuse of statins.

METHODS

We used US National Health and Nutrition Examination Survey data (2011-2016) and identified 706 cancer survivors and matched controls (1:2) by age and sex. We identified participants who met the American College of Cardiology/American Heart Association (2018) guidelines but were not currently in treatment. We estimated the proportion of patients who were statin-eligible but untreated and performed multivariable logistic regression analysis to identify the factors associated with underuse of statins.

RESULTS

The mean age of the total sample was 62.2 years (standard deviation, 9.1). Among the total participants, 37.5% of cancer survivors and 37.2% of controls were statin-eligible but untreated. The crude statin-eligible untreated proportion was 41.2% among cancer survivors who had received a cancer diagnosis within 3 years and 40.3% among long-term survivors of 10 years or more. In multivariate analysis, old age, male sex, lack of a usual source of care, current smoking, and low household income were significantly associated with statin-eligible untreated status.

CONCLUSIONS AND IMPLICATIONS FOR CANCER SURVIVORS

More than one-third of cancer survivors were statin-eligible but untreated under current guidelines. There is room for improvement to reduce the burden of non-cancer mortality by managing traditional cardiovascular risk factors.

Statin and Cancer Mortality and Survival: An Umbrella Systematic Review and Meta-Analysis

The aim of this study is to provide an overview and understand the strength of evidence and the extent of potential biases and the validity of claimed associations between the use of statins and cancer mortality or survival. We performed a comprehensive umbrella review of meta-analyses and systematically appraised the relevant meta-analyses of observational studies on the associations between statin use and cancer mortality or survival in various kinds of cancer. We searched the PubMed database and screened the reference list of relevant articles. We obtained the summary effect, 95% confidence interval, heterogeneity, and also examined small study effects and 95% prediction intervals for effect sizes, and the level of evidence was determined from the criteria. Regarding cancer mortality, statin use showed convincing evidence for an association with a reduced cancer-specific mortality rate for colorectal cancer. Four associations with reduced all-cause mortality (for breast cancer, colorectal cancer, endocrine-related gynecological cancer, and ovarian cancer) had a suggestive evidence. Moreover, analyses in nine cancers showed a weak level of evidence, while the remaining 15 did not indicate significant changes in either direction. Although there was a preventive effect of statin on cancer mortality in some cancer types, the evidence supporting the use of statins to reduce cancer mortality or survival was low.

Effects of statin exposure and lung cancer survival: A meta-analysis of observational studies

Statin exposure has been reported to improve survival in several cancers. However, studies evaluating the association between statins and prognostic outcomes in patients with lung cancer are conflicting and heterogeneous. Pubmed, EMBASE and reference lists of included studies were searched to identify studies investigating the association between statin exposure and lung cancer prognosis. The primary outcome measure was overall survival (OS) and secondary ones included cancer-specific survival (CSS) and recurrence-free survival (RFS). Hazard ratios (HRs) with 95% confidence intervals (95% CIs) of these outcomes were pooled using random-effects models. Thirteen studies with data from 99,297 individuals satisfying the inclusion criteria were identified. Studies were ranked to be at low to moderate risk of bias. Meta-analysis showed that statin exposure was significantly associated with improved OS (pooled HR 0.79, 95% CI 0.72-0.86), CSS (pooled HR 0.83, 95% CI 0.77-0.89) and RFS (pooled HR 0.85, 95% CI 0.81-0.89). Subgroup analyses showed that statin users after diagnosis of lung cancer had more survival benefit for OS (HR 0.68, 95% CI 0.51-0.92) than those before diagnosis (HR 0.86, 95% CI 0.81-0.90) and current users (HR 0.79, 95% CI 0.62-1.02) (P for interaction <0.001). Besides, statin users were likely to have more survival benefits in stage IV lung cancer patients (HR 0.77, 95% CI 0.74-0.79) than in mixed stage (I-IV or I-III) patients (P for interaction = 0.004). Statin exposure is associated with significantly improved survival in patients with lung cancer. Future studies are warranted to further demonstrate the therapeutic role of statins in specific lung cancer patients.

Current state and outlook for drug repositioning anticipated in the field of ovarian cancer

Ovarian cancer is the seventh most common cancer and the eighth most common cause of cancer mortality in women. Although standard chemotherapy is the established treatment for ovarian cancer, the prognosis remains poor, and it is highly anticipated that new drugs will be developed. New drugs, such as humanized anti-vascular endothelial growth factor monoclonal antibodies and poly ADP-ribose polymerase inhibitors, are expected to improve clinical outcomes of ovarian cancer. However, long-term, costly research is required to develop such new drugs, and soaring national healthcare costs are becoming a concern worldwide. In this social context, drug repositioning, wherein existing drugs are used to develop drugs with new indications for other diseases, has recently gained attention. Because trials have already confirmed the safety in humans and the pharmacokinetics of such drugs, the development period is shorter than the conventional development of a new drug, thereby reducing costs. This review discusses the available basic experimental and clinical data on drugs used for other types of cancer for which drug repositioning is anticipated to repurpose the drug for the treatment of ovarian cancer. These include statins, which are used to treat dyslipidemia; bisphosphonate, which is used to treat osteoporosis; metformin, which is used to treat diabetes; non-steroidal anti-inflammatory drugs; ivermectin, an antiparasitic agent; and itraconazole, an anti-fungal agent. These drugs will play an important role in future drug repositioning strategies for ovarian cancer. Furthermore, drug repositioning is anticipated to extend not only to ovarian cancer treatment but also to ovarian cancer prevention.

Impact of postdiagnostic statin use on ovarian cancer mortality: A systematic review and meta-analysis of observational studies

AIMS

To comprehensively evaluate the association between postdiagnostic statin use and mortality of ovarian cancer (OC) patients.

METHODS

Using a comprehensive strategy, multiple databases (Medline, Embase and Web of Science) were systematically searched to identify observational studies that examined the correlation between statin use and OC mortality up to 31 December 2017. The studies were independently reviewed and selected based on predetermined selection criteria. Data were extracted independently and in duplicate. The risk of bias was evaluated with the Newcastle-Ottawa scale. Hazard ratios (HRs) and 95% confidence intervals (CIs) for mortality were summarized with a profile likelihood random effects model.

RESULTS

Of 269 studies, eight cohort studies of 19 904 OC patients met the inclusion criteria. Postdiagnostic statin use was inversely associated with all-cause mortality/overall survival (summarized HR = 0.74; 95%CI = 0.63-0.87; I²  = 55%; n = 7) and cancer-specific mortality (summarized HR = 0.87; 95%CI = 0.80-0.95; I²  = 0%; n = 3) of OC patients. These findings were consistent by subgroup analyses stratified by study and patient characteristics as well as adjustments made for potential confounders. A meta-regression analysis found no effect of modification by these variables. Of note, similar significant inverse effects were also observed when increasing the intensity (highest vs. lowest) of postdiagnostic statin use (summarized HR = 0.84; 95%CI = 0.74-0.96; I²  = 0%; n = 3).

CONCLUSION

Postdiagnostic statin use can improve the survival of patients with OC. Further prospective cohort and randomized controlled trials are warranted to confirm the therapeutic role of statin use on the outcome of OC.