Challenges in translating endpoints from trials to observational cohort studies in oncology

Effects of oily fish and its fatty acid intake on non-alcoholic fatty liver disease development among South Korean adults

Background

The benefits of fish fatty acid intake for non-alcoholic fatty liver disease (NAFLD) are rarely reported, although a previous study assessed the relationship between oily fish consumption and the prevalence of NAFLD.

Aims

We investigated whether oily fish and fish-based monounsaturated fatty acids, polyunsaturated fatty acids, and omega-3 fatty acids affect the development of NAFLD in South Korean adults.

Methods

In this large-scale cohort study, 44,139 participants of the Health Examinees study were selected for analysis after 5 years of follow-up. NAFLD is diagnosed with a non-invasive index, the fatty liver index. Using multivariable Cox proportional hazards models, adjusted for age, body mass index, total energy intake, education, physical activity, smoking status, and drinking (alcohol) status, we calculated the hazard ratios and 95% confidence intervals.

Results

For men, NAFLD had no statistically significant associations with quartiles of total oily fish or its fatty acid intake. However, among women, an inverse association was observed (all p for trend <0.05). Regarding the standard deviation (SD) increment of total oily fish or its fatty acid intake by one, all fatty acids from oily fish showed inverse associations for NAFLD in both men and women. After stratified analyses, we found that drinking status and menopause status were independent risk factors for NAFLD. Oily fish or its fatty acid intake has the same benefit pattern on metabolic dysfunction-associated fatty liver disease as NAFLD.

Conclusion

Oily fish and its fatty acid intake showed a preventative benefit for NAFLD and metabolic dysfunction-associated fatty liver disease, especially in South Korean women.

A Systematic Review of the Sex and Gender Reporting in COVID-19 Clinical Trials

Sex and gender have implications for COVID-19 vaccine efficacy and adverse effects from the vaccine. As vaccination is one of the key responses to the COVID-19 pandemic, it is vital that sex and gender differences be acknowledged, measured, and analysed in clinical research. Here, we systematically review published COVID-19 vaccine trials, both interventional and observational, to assess the quality of reporting of sex and gender. Of the 75 clinical trials on COVID-19 vaccines included in this review, only 24% presented their main outcome data disaggregated by sex, and only 13% included any discussion of the implications of their study for women and men. Considering the sex differences in adverse events after vaccination, and the gendered aspects of vaccine hesitancy, these oversights in clinical research on vaccines have implications for recovery from the COVID-19 pandemic and for wider public health.

Overall Survival Among Chemotherapy-Naive Patients With Castration-Resistant Prostate Cancer Under Abiraterone Versus Enzalutamide: A Direct Comparison Based on a 2014-2018 French Population Study (the SPEAR Cohort)

Abiraterone acetate (ABI) and enzalutamide (ENZ) are considered to be clinically relevant comparators among chemotherapy-naive patients with castration-resistant prostate cancer. No clinical trials comparing overall survival with ABI versus ENZ in a head-to-head approach have been published so far. A few observational studies with low power suggested a potential benefit of ENZ. We used the French National Health Data System to compare overall survival of new users of ABI and ENZ among chemotherapy-naive patients with castration-resistant prostate cancer in 2014-2017, followed through 2018 (the SPEAR cohort, a 2014-2018 cohort study). With an intent-to-treat approach, a survival analysis was performed, estimating hazard ratios for overall survival with the inverse probability weighted Cox model method. Among 10,308 new users, 64% were treated with ABI and 36% with ENZ. The crude mortality rate was 25.2 per 100 person-years (95% confidence interval (CI): 24.4, 26.0) for ABI and 23.7 per 100 person-years (95% CI: 22.6, 24.9) for ENZ. In the weighted analysis, ENZ was associated with better overall survival compared with ABI (hazard ratio = 0.90 (95% CI: 0.85, 0.96) with a median overall survival of 31.7 months for ABI and 34.2 months for ENZ). When restricting to 2015-2017 new users, the effect estimate shifted up to a hazard ratio of 0.93 (95% CI: 0.86, 1.01).

Occult Metastasis in Laryngeal Squamous Cell Carcinoma: A Systematic Review and Meta-Analysis

OBJECTIVE

The incidence of occult metastasis (OM) in laryngeal squamous cell carcinoma (SCC) is still widely debated. In this systematic review, we aim to determine the rate of OM in laryngeal SCC, its impact on recurrence, and the role of elective neck dissection (END) in the management of the clinically negative neck.

METHODS

A systematic review of the English-language literature in Web of Science, PubMed, MEDLINE, and Cochrane Library databases on occult metastasis in laryngeal SCC from 1977 to 2018 was conducted. Studies evaluating occult metastasis (OM) in patients with laryngeal SCC with clinically negative necks undergoing surgery were included. Studies evaluating other head and neck subsites, clinically node positive, and salvage patients were excluded.

RESULTS

Twenty-one articles with a total of 5630 patients were included. The overall rate of OM was 20.5% and was 23% and 12.2% in supraglottic and glottic tumors, respectively. The OM rate in T1-T2 tumors was 13% and 25% in T3-T4 tumors. T3-T4 tumors had significantly greater odds of developing OM compared to T1-T2 tumors (Odds Ratio [OR] = 2.61, 95% Confidence Interval [CI] = 1.92-3.55, P < .00001). Patients with OM were more likely to develop distant metastasis (OR = 5.65, 95% CI = 3.36-9.51, P < .00001).

CONCLUSIONS

Patients with advanced T-stage laryngeal SCC should undergo elective neck treatment. More aggressive treatment for patients with history of OM should be considered due to the risk of subsequent regional and distant metastasis.

LEVEL OF EVIDENCE

II.

Observational designs in clinical multiple sclerosis research: Particulars, practices and potentialities

Observational studies investigate a wide range of topics in multiple sclerosis research. This paper presents an overview of the various observational designs and their applications in clinical studies. Observational studies are well suited for making discoveries and assessing new explanations of phenomena, but less so for establishing causal relationships, due to confounding by indication (selection bias), co-morbidity, socio-economic or other factors. Whether observational findings are demonstrative, indicative or only suggestive, depends on the research question, whether and how the design fits this question, analytical techniques, and the quality of data. Observational studies may be cross-sectional vs. longitudinal, and prospective vs. retrospective. The term 'retrograde' is proposed to explicate that cross-sectional studies may obtain data that cover (long) preceding periods. Case reports and case series are usually based on accidental observations or routinely collected data. Cross-sectional studies, by simultaneously assessing clinical phenomena and external factors, enable the discovery and quantification of associations. In ecological studies the unit of analysis is population or group, and relationships on patient level cannot be established. A cohort study is a longitudinal study that investigates patients with a defining characteristic, e.g. diagnosis or specific treatment, by analyzing data acquired at various intervals. Prospective cohort studies use (some) data that are not yet available at the time the research is conceived, whereas in retrospective studies the data already exist. In a case-control study a representative group of patients with a specific clinical feature is compared with controls, and the frequencies at which an external factor, e.g. infection, has occurred in each group is compared; in a nested case-control study controls are drawn from a fully known cohort. Randomized controlled trial (RCT)-extension studies are informative because, due to RCT randomization, they are free from confounding by indication. Patient or disease registries are organised systems for the long-term collection of uniform data on a population that is defined by a particular disease, condition or exposure, with the purpose to study changes over time. In pharmacotherapeutic research, accidental observations of unexpected beneficial effects may lead to further research into a drug's efficacy in other conditions. Uncontrolled phase 1 studies investigate safety and dosing aspects. Observational studies are alternatives to RCTs when these are not feasible for ethical or practical reasons. Phase 4 observational studies play a crucial role in the evaluation of the effectiveness of treatments in daily practice, the validation of RCT-based side effect profiles, and the discovery of late occurring or rare, potentially life-threatening side effects. Combinations of multidisciplinary longitudinal data bases into large data sets enable the development of algorithms for personalized treatments. To improve the reporting of observational findings on treatment effectiveness, it is proposed that abstracts define the research question(s) the study was meant to answer, study design and analytical methods, and identify and quantify the patient population, treatment of interest, relevant outcomes and the study's strengths and limitations. The development of guidelines for Strengthening the Reporting of Observational Studies in Effectiveness Research (STROBER), as an extension of the guidelines used in epidemiology, is wanted.

Is lipid goal one-size-fits-all: A review of evidence for recommended low-density lipoprotein treatment targets in Asian patients

The international guideline recommendations for low-density lipoprotein cholesterol (LDL-C) lowering were made based on the results of randomized controlled trials (RCTs), meta-analyses, and observational studies mostly in the White population. It was not clear whether these LDL-C targets could be applicable to other ethnic groups, for example, Asian patients. This review aimed to address major aspects related to the lipid goal and statin therapy in Asia, including the epidemiology of cardiovascular disease, the LDL-C profiles, the lipid goals from localized guidelines, genetics and lifestyles, and the efficacy and safety of statins. Owing to the geographic, ethnic, genetic, and cultural diversity in this region, we observed a geographic pattern of diversity in cardiovascular epidemiology and statin response in Central Asia, East Asia (particularly for Asia-Pacific region), and South Asia. The rapidly growing literature from Asian countries questioning "lower is better" hypothesis was noticed. However, owing to the nature of these dominantly observational data, the conclusion was hardly confirmative. Despite the rapid expansion of the current literature in this region, efforts should be made to ensure an adequate sample size to assess the significance of a given lipid parameter on overall cardiovascular outcomes in this Asian population.

Real-world use of bevacizumab in metastatic colorectal, metastatic breast, advanced ovarian and cervical cancer: a systematic literature review

AIM

This review aims to assist physicians and payers in assessing the efficacy and safety of bevacizumab in real-world clinical practice by identifying evidence on the comparative effectiveness and safety of bevacizumab in its most frequent indications. Materials & methods: In a systematic review of the published literature, electronic databases (Embase^®, MEDLINE^® and the Cochrane Library) were searched in May 2016 and updated in January 2017; 20 scientific congresses were searched in 2014-2017.

RESULTS

Of 61 included publications, 49, eight, four and 0 concerned metastatic colorectal cancer, metastatic breast cancer, advanced ovarian cancer and cervical cancer, respectively. Fifteen publications (metastatic colorectal cancer) reported on factors predictive of response to therapy.

CONCLUSION

Effectiveness findings from real-world studies broadly supported results from registration studies.

Informed Consent: A Clinical Trials Perspective

The primary goal of the thousands of registered trials in cancer research is to extend survival. With evaluation of efficacy, safety, and tolerability, healthcare providers must ensure that the principles described in the Belmont Report are upheld and that patients are truly informed when signing a consent form. In this article, two cases are highlighted, and reasons for participating in clinical trials are discussed. Challenges, such as healthcare literacy, patients' dedication to their healthcare providers, and choosing between multiple trials, are also explored.