The role of meta-analyses in assessing cancer treatments

Clinical value of long noncoding RNA ZEB1 anti-sense1 in cancer patients: A meta-analysis

BACKGROUND

The high expression of long noncoding RNA ZEB1 anti-sense1 (ZEB1-AS1) has been reported in several types of cancer. However, most studies investigating this phenomenon were either case reports or used small patient samples. The objective of this meta-analysis was to clarify the potential clinical values of ZEB1-AS1 in various cancers.

MATERIALS AND METHODS

The PubMed-MEDLINE, Web of Science, and EMBASE databases were searched, using systematic search terms, to find relevant research reports on this subject. The combined hazards ratios (HRs) and corresponding 95% confidence intervals (CIs) were calculated to explore the association between ZEB1-AS1 expression and overall survival (OS). The combined odd ratios (ORs) were calculated to evaluate the association between ZEB1-AS1 expression and pathological parameters. Data analysis was conducted in R software version 3.4.2. and Stata version 12.0 (College Station, TX: Stata Corp LP).

RESULTS

Ten studies including 963 cancer patients were selected as suitable for this study. The pooled hazards ratio (HR) indicated that high ZEB1-AS1 expression was strongly associated with poor OS (pooled HR = 2.26, 95% CI: 1.80-2.85, P < .0001) in the Chinese cancer patients. Also, a high expression of ZEB1-AS1 was related to metastasis (pooled HR = 3.38, 95% CI: 1.91-6.00, P < .0001), and advanced tumor stage (pooled HR = 0.48, 95% CI: 0.29-0.81, P = .005). The up-regulation of ZEB1-AS1 was not significantly associated with histological differentiation (P = .39), sex (P = .001), and age (P = .372) of cancer patients.

CONCLUSION

The high expression of ZEB1-AS1 significantly predicted poor OS, poor metastasis, and high tumor stage in cancer patients, demonstrating that high ZEB1-AS1 expression may serve as a biomarker of poor prognosis in the Chinese cancer patients.

Acid ceramidase 1 expression correlates with a better prognosis in ER-positive breast cancer

OBJECTIVES

Ceramide and sphingosine mediate response to cancer therapy, inhibit cell growth and induce apoptosis in vitro. Only a few clinical data about the impact of ceramide and sphingosine iny vivo are available. We investigated the relevance of ceramide- and sphingosine-generating enzymes in breast cancer (acid ceramidase 1 (ASAH1), ceramide synthases 4 (LASS4) and 6 (LASS6)) by means of gene expression analysis.

METHODS

We analyzed differences in ASAH1, LASS4 and LASS6 on mRNA level between breast cancer subgroups using microarray data from 1581 tumor samples.

RESULTS

High ASAH1, LASS4 and LASS6 expression correlates with pathohistological grading (p < 0.001) and estrogen receptor (ER) status (p < 0.001). High ASAH1 expression was associated with a larger tumor size >2 cm (p = 0.003), while high LASS6 expression was correlated with ErbB2 negativity (p < 0.001). In survival analysis, we detected a significant better prognosis of patients with higher ASAH1 expression (p = 0.002) in the ER-positive subgroup. In contrast, expression of LASS4 or LASS6 did not show any prognostic impact. In the multivariate analysis, only ASAH1 expression (p = 0.002), tumor size (p < 0.0001) and ErbB2 positivity (p = 0.041) remained significant.

CONCLUSION

ASAH1 is an estrogen-dependent member of the sphingolipid metabolism, which might provide further prognostic information in ER-positive breast cancers.

Management of the clinically negative neck (N0) of supraglottic laryngeal carcinoma: a systematic review

AIM

The most effective therapeutic approach for patients with supraglottic laryngeal carcinoma (SGLC) and clinically negative neck (cN0) remains a subject of much debate. The purpose of this systematic review was to answer the following question: among patients with SGLC and cN0 neck, are the survival and occurrence of neck metastases significantly different between patients that received neck dissection and those that had another therapeutic treatment (radiotherapy, combined therapy, 'wait and see' policy)?

MATERIALS AND METHODS

An electronic literature search was performed in MEDLINE, EMBASE, Cochrane Library and CENTRAL databases, followed by extensive hand-searching for the identification of relevant studies. The following inclusion criteria were established: the study should (a) include a comparison of neck dissection with one of the other therapeutic procedures for cN0 of SGLC; (b) report the therapy for the initial supraglottic cancer; and (c) use time-to-event analysis of its results. Six studies were eventually identified and systematically reviewed.

RESULTS

All studies included in the systematic review were retrospective (n=792 patients). The survival (overall, disease-specific and neck disease-free) and the site of neck recurrence of the patients with N0 supraglottic cancer were not significantly different between patients in the neck dissection treatment group and those of the rest of the therapeutic strategies examined (neck radiotherapy, combined therapy and 'wait and see' policy).

CONCLUSIONS

The present systematic review highlights the need for further well-designed prospective studies that will provide more reliable answers to the debatable issue of the management of cN0 of SGLC. Currently, based on the best available evidence, it seems that neck dissection is not superior to radiotherapy or combined therapy or a 'wait and see' policy in terms of survival and control of neck disease.

Comparison of docetaxel- and vinca alkaloid-based chemotherapy in the first-line treatment of advanced non-small cell lung cancer: a meta-analysis of seven randomized clinical trials

INTRODUCTION

To compare the impact on overall survival (OS) of docetaxel-based chemotherapy versus vinca alkaloid-based regimens for first-line therapy of advanced non-small cell lung cancer.

METHODS

A meta-analysis of all randomized, controlled trials comparing docetaxel- and vinca alkaloid-based chemotherapy was undertaken using MEDLINE, CANCERLIT, MEDSCAPE, Google Scholar, the Cochrane Library, the National Institutes of Health randomized, controlled trials register, and conference proceedings, supplemented by information from clinical study reports. All published and unpublished randomized, controlled trials (in any language) were included. Analysis was based on pooling individual logarithms of the hazard ratio for OS and the odds ratio (OR) for safety.

RESULTS

From eight potentially eligible trials, seven were selected (n = 2867). Docetaxel was administered with a platinum agent (three trials), with gemcitabine (two trials), or as monotherapy (two trials). Vinca alkaloid (vinorelbine [six trials] and vindesine [one trial]) was administered with cisplatin (six trials) or alone (one trial). The pooled estimate for OS showed an 11% improvement in favor of docetaxel (hazard ratio = 0.89; 95% confidence interval: 0.82-0.96; p = 0.004). Sensitivity analyses considering only vinorelbine as a comparator or only the doublet regimens showed similar improvements. Grade 3/4 neutropenia and grade 3/4 serious adverse events were less frequent with docetaxel- versus vinca alkaloid-based regimens (OR = 0.59; 95% confidence interval: 0.38-0.89; p = 0.013 and OR = 0.68; 95% confidence interval: 0.55-0.84; p < 0.001, respectively).

CONCLUSION

According to this meta-analysis, docetaxel is superior to vinca alkaloid-based regimens in terms of OS and safety for first-line therapy of advanced non-small cell lung cancer.

The strengths and limitations of meta-analyses based on aggregate data

BACKGROUND

Properly performed systematic reviews and meta-analyses are thought by many to represent among the highest level of evidence addressing important clinical issues. Few would disagree that meta-analyses based on individual patient data (IPD) offer several advantages and represent the standard to which all other systematic reviews should be compared.

METHODS

All cancer-related meta-analyses cited in Medline were classified as based on aggregate or individual patient data. A review was then undertaken of all reports comparing the comparative strengths and limitations of meta-analyses using either aggregate or individual patient data.

RESULTS

The majority of published meta-analyses are based on summary or aggregate patient data (APD). Reasons suggested for this include the considerable resources, years of study and often, broad international cooperation required for IPD meta-analyses. Many of the most important features of systematic reviews including formal meta-analyses are addressed by both IPD and APD meta-analyses. The need for defining an explicit and relevant clinical question, exhaustively searching for the totality of evidence, meticulous and unbiased data transfer or extraction, assessment of between study heterogeneity and the use of appropriate statistical methods for estimating summary effect measures are essentially the same for the two approaches.

CONCLUSION

IPD offers advantages and, when feasible, should be considered the best opportunity to summarize the results of multiple studies. However, the resources, time and cooperation required for such studies will continue to limit their use in many important areas of clinical medicine which can be meaningfully and cost-effectively approached by properly performed APD meta-analyses. APD meta-analyses continue to be the mainstay of systematic reviews utilized by the US Preventive Services Task Force, the Cochrane Collaboration and many professional societies to support clinical practice guidelines.

State-of-the-art treatment of high-grade brain tumors

The incidence of primary brain tumors has rapidly increased in recent years. The current standard of care for patients with high-grade malignant glioma is resection followed by radiotherapy. However, the use of adjuvant chemotherapy and the standard of care at first relapse are still under debate for patients with glioblastoma multiforme and anaplastic astrocytoma. Meta-analyses have suggested that adjuvant chemotherapy, specifically with nitrosourea-based regimens, is associated with improved survival. However, no randomized, controlled trial has shown a clear advantage for adjuvant chemotherapy in these patients. Cumulative toxicity associated with both radiotherapy and chemotherapy, as well as resistance to nitrosourea-based regimens related to exposure in the adjuvant setting, prevent the use of radiotherapy and nitrosourea-based regimens at first relapse. The combination of procarbazine, carmustine, and vincristine (PCV) has shown activity at first relapse in patients who have not received adjuvant chemotherapy. Temozolomide (Temodar [US], Temodal [international]; Schering-Plough Corporation, Kenilworth, NJ) has shown activity at both first and second relapse in patients who have received prior nitrosourea-based regimens. The better safety profile of temozolomide suggests that it may be preferred to PCV for treatment of patients with recurrent high-grade malignant glioma. Additional randomized, controlled trials are needed to fully define the best option for first-line chemotherapy in both the adjuvant and recurrent settings in patients with high-grade malignant glioma.

Exercise and lumbar spine bone mineral density in postmenopausal women: a meta-analysis of individual patient data

BACKGROUND

Low bone mineral density (BMD) at the lumbar spine is a major public health problem among postmenopausal women. We conducted a meta-analysis of individual patient data (IPD) to examine the effects of exercise on lumbar spine BMD in postmenopausal women.

METHODS

IPD were requested from a previously developed database of summary means from randomized and nonrandomized trials dealing with the effects of exercise on BMD. Two-way analysis of variance tests with pairwise comparisons (p < or =.05) and 95% confidence intervals (CIs) were used to determine the statistical significance for changes in lumbar spine BMD.

RESULTS

Across 13 trials that included 699 subjects (355 exercise, 344 control), a statistically significant interaction was found between test and group (F = 15.232, p =.000). Pairwise comparisons (Bonferroni t tests) revealed a statistically significant increase in final minus initial BMD for the exercise group ( +/- SD = 0.005 +/- 0.043 g/cm(2), t = 2.46, p =.014, 95% CI = 0.001-0.009) and a statistically significant decrease in final minus initial BMD for the control group ( +/- SD = -0.007 +/- 0.045 g/cm(2), t = -3.051, p =.002, 95% CI = -0.012--0.002). Changes were equivalent to an approximate 2% benefit in lumbar spine BMD (exercise, +1%, control, -1%).

CONCLUSIONS

The results of this IPD meta-analysis suggest that exercise helps to improve and maintain lumbar spine BMD in postmenopausal women.

Statistical methodology of phase III cancer clinical trials: advances and future perspectives

The methodology for conducting cancer clinical trials has undergone enormous changes over the past 25-30 years since the EORTC Data Center was created. The purpose of this paper is to highlight and to provide a historical perspective for the main methodological concepts, both practical and theoretical, which form the basis for the design and analysis of phase III cancer clinical trials within the EORTC Data Center. Some statistical aspects of other associated topics such as quality of life, health economics, meta-analysis and treatment outcome will also be briefly discussed. Finally, some future perspectives and topics for further statistical methodological research will be presented in order to spur statisticians to meet the challenge of efficiently designing and analysing the clinical trials of tomorrow.

Meta-analyses of randomised clinical trials in oncology

A meta-analysis is a quantitative synthesis of randomised clinical trials, used to evaluate moderate treatment effects in oncology. It is complementary to large-scale trials. We describes the principles, methods, and limits of meta-analyses. The gold standard for a meta-analysis is to obtain individual patient data directly from each principal investigator, but this is time-consuming and costly. The main steps of a meta-analysis using individual patient data are described. Multidisciplinary collaboration is needed for clinical insight and critical review of the data and results. Meta-analysis should include an evaluation of the trial quality, a quantification of the overall treatment effect, a study of the variations seen in this effect between trials, and pre-planned exploratory analyses to identify groups of patients who may benefit more from the treatment. Statistical methods are explained using real working examples. Since literature-based meta-analysis can lead to seriously biased assessments, meta-analyses of individual patient data should be undertaken systematically when long-term follow-up is needed, when a detailed analysis is important, or when the literature-based meta-analyses are not in agreement. The main factors which influence the quality of a meta-analysis are discussed.