The Need for Systematic Reviews in Oncology

Determinants of delayed childhood cancer care in low- and middle-income countries: A systematic review

Early access to care is essential to improve survival rates for childhood cancer. This study evaluates the determinants of delays in childhood cancer care in low- and middle-income countries (LMICs) through a systematic review of the literature. We proposed a novel Three-Delay framework specific to childhood cancer in LMICs by summarizing 43 determinants and 24 risk factors of delayed cancer care from 95 studies. Traditional medicine, household income, lack of transportation, rural population, parental education, and travel distance influenced most domains of our framework. Our novel framework can be used as a policy tool toward improving cancer care and outcomes for children in LMICs.

Comparative efficacy and safety of immune checkpoint inhibitors for unresectable advanced melanoma: A systematic review and network meta-analysis

BACKGROUND

Immune checkpoint inhibitors (ICIs) have entered the treatment paradigm for unresectable advanced melanoma, but there is a lack of evidence regarding its relative efficacy and safety. This study aim to compare the efficacy and safety of ICIs in patients with advanced unresectable melanoma.

METHODS

Studies included randomized clinical trials (RCTs) that compared ICIs, or combination therapy of ICIs, or with chemotherapy drugs, different ICIs, or one of the ICIs at different dosing schedules. Random-effects models of Bayesian network meta-analysis were performed following the PRISMA reporting guideline. Primary outcomes were overall survival (OS) and progression-free survival (PFS). Secondary outcomes included objective response rate (ORR), disease control rate (DCR), and adverse events.

PROSPERO

CRD42021229086.

RESULTS

Twenty-four RCTs with 18 different treatment regimens for advanced melanoma involving 10,090 patients were included. Overall, nivolumab 1 mg/kg plus ipilimumab 3 mg/kg treatment regimen were associated with the highest beneficial effect on OS, PFS, and DCR. Closely followed by nivolumab 3 mg/kg plus ipilimumab 1 mg/kg, and nivolumab plus relatlimab treatment regimens. However, three regimens had less favorable safety profiles. Although ipilimumab 0.3 mg/kg was ranked as the best options with the lowest risk of grade ≥ 3 treatment or immune-related adverse events, less therapeutic benefit was performed. The pembrolizumab 10 mg/kg regimen may be the preferred treatment with relative higher efficiency and safety among the ICIs regimens reported, as well as the nivolumab 3 mg/kg regimen. Head-to-head trials showed similar results.

CONCLUSIONS

This study shown the preferred treatment regimens with relatively higher efficiency and safety among the reported ICI regimens. Our results may complement the current standard of care, while its direct drug comparisons will aid future trials.

Machine learning computational tools to assist the performance of systematic reviews: A mapping review

BACKGROUND

Within evidence-based practice (EBP), systematic reviews (SR) are considered the highest level of evidence in that they summarize the best available research and describe the progress in a determined field. Due its methodology, SR require significant time and resources to be performed; they also require repetitive steps that may introduce biases and human errors. Machine learning (ML) algorithms therefore present a promising alternative and a potential game changer to speed up and automate the SR process. This review aims to map the current availability of computational tools that use ML techniques to assist in the performance of SR, and to support authors in the selection of the right software for the performance of evidence synthesis.

METHODS

The mapping review was based on comprehensive searches in electronic databases and software repositories to obtain relevant literature and records, followed by screening for eligibility based on titles, abstracts, and full text by two reviewers. The data extraction consisted of listing and extracting the name and basic characteristics of the included tools, for example a tool's applicability to the various SR stages, pricing options, open-source availability, and type of software. These tools were classified and graphically represented to facilitate the description of our findings.

RESULTS

A total of 9653 studies and 585 records were obtained from the structured searches performed on selected bibliometric databases and software repositories respectively. After screening, a total of 119 descriptions from publications and records allowed us to identify 63 tools that assist the SR process using ML techniques.

CONCLUSIONS

This review provides a high-quality map of currently available ML software to assist the performance of SR. ML algorithms are arguably one of the best techniques at present for the automation of SR. The most promising tools were easily accessible and included a high number of user-friendly features permitting the automation of SR and other kinds of evidence synthesis reviews.

Commentary: On the reliability of causal claims

Causal assessments in epidemiology are a complex process due to the many methods involved. The general scientific method lords over the process joined by study designs and statistical methods. Other methods include those that evaluate quality and bias along with the research synthesis methods such as the systematic narrative review, meta-analysis, and the criteria-based methods. When different investigators apply these methods to the same evidence and come up with different causal assessments, as described in the review by Goodman et al. in this issue, a key question becomes, how can the differences be explained? A prime candidate involves different methodologic choices. A deeper question emerges from this same situation: are the methods used for causal assessments reliable? Reliability is a hallmark of scientific practice. The methods used to make claims about causality should be reliable. Given the complexity of the causal assessment process, an objective evaluation of reliability is challenging but clearly worth the effort. Fortunately, Hill's criterion of analogy, much maligned in epidemiology, provides a clue. This commentary explores the issue of the reliability of causal claims using the Goodman et al. systematic review as its foil along with the claims by EPA, IARC, and ATSDR about the relationship between perchloroethylene and non-Hodgkin lymphoma, the claims Goodman et al. believe are wrong.

Safety and efficacy of nivolumab compared with other regimens in patients with melanoma: A network meta-analysis

BACKGROUND

Melanoma is a cancerous tumor that develops from melanocytes in the epidermal basal layer of the skin. It is a fatal skin cancer and the third most common kind of cutaneous tumor. We aim to evaluate the effect of nivolumab in melanoma patients compared with other regimens.

METHODS

This meta-analysis included only clinical trials, both randomized and nonrandomized. The main outcomes of interest were the response to treatment, overall survival (OS), progression-free survival, and adverse events.

RESULTS

The overall effect estimates favored nivolumab group over the combination of nivolumab plus ipilimumab (HR 3.06, 95% CI 1.70-5.49) and chemotherapy group (HR 3.58, 95% CI 1.63-7.84) after 1 year. Compared to chemotherapy, nivolumab had lower rates of adverse events.

CONCLUSION

Nivolumab monotherapy yields high progression-free survival rates and has the same efficacy when combined with ipilimumab in a 1-year OS. However, after 2 and 3 years of follow-up, the combined regimen has more OS rates.

Health utilities in pediatric cancer patients and survivors: a systematic review and meta-analysis for clinical implementation

PURPOSE

Health utility (HU) is a useful metric for evaluating cost and utility of cancer therapies or prioritizing healthcare resources. We conducted a meta-analysis to compare HUs in association with clinical parameters and identify missing cancer-related themes from the extant HU measures for pediatric cancer patients and survivors.

METHODS

Studies published in the PubMed, Embase, Web of Science, and Cochrane Library were identified. Meta-analyses were performed to estimate weighted means of HUs assessed by self- and proxy-responses. Mixed-effects meta-regressions were applied to compare HUs between cancer patients/survivors and general populations. Missing themes in the extant measures were identified based on established patient-reported outcomes frameworks.

RESULTS

Of 123 selected studies included pediatric cancer populations, 44% used the Health Utilities Index version 2 (HUI2), and 48% used version 3 (HUI3). Compared to general populations, cancer patients undergoing therapies for acute lymphoblastic leukemia (ALL) had 0.129 (95% CI - 0.183 to - 0.075) and brain tumor had 0.257 (95% CI - 0.354 to - 0.160) lower HUs per proxy-reported HUI3, whereas survivors of ALL had 0.028 (95% CI - 0.062 to 0.007) and brain tumor had 0.188 (95% CI - 0.237 to - 0.140) lower HUs per proxy-reported HUI3. Compared to general populations, cancer patients treated with multimodality therapy and survivors off therapy 2-5 years had significantly poorer HUs (p's < 0.05). Missing cancer-specific contents from the HU measures were identified.

CONCLUSION

Pediatric cancer patients and survivors had poorer HUs than general populations. It is important to select appropriate HUs for economic evaluations, and offer interventions to minimize HU deficits for particular cancer populations.

An analysis of the evidence underpinning the national comprehensive cancer network practice guidelines

OBJECTIVE

This study assesses the quality and completeness of systematic reviews (SRs) included by the National Comprehensive Cancer Network (NCCN) cancer screening clinical practice guidelines (CPGs).

METHODS

We evaluated SRs according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) and AMSTAR-2 (A Measurement Tool to Assess systematic Reviews).

RESULTS

Seven NCCN CPGs were included with 109 SRs. The mean PRISMA percent completeness of included SRs was 71 % (range 0.1-1.0). The mean AMSTAR-2 percent completeness was 56 % (range 0.05-0.99). Of the 70 SRs assessed via AMSTAR-2, 42 (60 %) received a "critically low" rating, 11 (15.7 %) received "low" ratings, and 17 (24.3 %) received "moderate". None of the SRs received a "high" rating.

CONCLUSION

Lack of adherence to AMSTAR-2 and PRISMA reporting standards among the SRs included is prevalent. We suggest improved reporting of SR inclusion criteria and evaluation to bolster the reporting quality of SRs underpinning CPG recommendations.

Does paraquat cause Parkinson's disease? A review of reviews

To examine the extent to which a consensus exists in the scientific community regarding the relationship between exposure to paraquat and Parkinson's disease, a critical review of reviews was undertaken focusing on reviews published between 2006 and the present that offered opinions on the issue of causation. Systematic searches were undertaken of scientific databases along with searches of published bibliographies to identify English language reviews on the topic of paraquat and Parkinson's disease including those on the broader topic of environmental and occupational risk factors for Parkinson's disease. Of the 269 publications identified in the searches, there were twelve reviews, some with meta-analyses, that met the inclusion criteria. Information on methods used by the reviewers, if any, and source of funding was collected; the quality of the reviews was considered. No author of any published review stated that it has been established that exposure to paraquat causes Parkinson's disease, regardless of methods used and independent of funding source. A consensus exists in the scientific community that the available evidence does not warrant a claim that paraquat causes Parkinson's disease. Future research on this topic should focus on improving the quality of epidemiological studies including better exposure measures and identifying specific mechanisms of action. Future reviews of emerging evidence should be structured as systematic narrative reviews with meta-analysis if appropriate.

A systematic literature review and network meta-analysis of effectiveness and safety outcomes in advanced melanoma

BACKGROUND

Although a myriad of novel treatments entered the treatment paradigm for advanced melanoma, there is lack of head-to-head evidence. We conducted a network meta-analysis (NMA) to estimate each treatment's relative effectiveness and safety.

METHODS

A systematic literature review (SLR) was conducted in Embase, MEDLINE and Cochrane to identify all phase III randomised controlled trials (RCTs) with a time frame from January 1, 2010 to March 11, 2019. We retrieved evidence on treatment-related grade III/IV adverse events, progression-free survival (PFS) and overall survival (OS). Evidence was synthesised using a Bayesian fixed-effect NMA. Reference treatment was dacarbazine. In accordance with RCTs, dacarbazine was pooled with temozolomide, paclitaxel and paclitaxel plus carboplatin. To increase homogeneity of the study populations, RCTs were only included if patients were not previously treated with novel treatments.

RESULTS

The SLR identified 28 phase III RCTs involving 14,376 patients. Nineteen and seventeen treatments were included in the effectiveness and safety NMA, respectively. For PFS, dabrafenib plus trametinib (hazard ratio [HR] PFS: 0.21) and vemurafenib plus cobimetinib (HR PFS: 0.22) were identified as most favourable treatments. Both had, however, less favourable safety profiles. Five other treatments closely followed (dabrafenib [HR PFS: 0.30], nivolumab plus ipilimumab [HR PFS: 0.34], vemurafenib [HR PFS: 0.38], nivolumab [HR PFS: 0.42] and pembrolizumab [HR PFS: 0.46]). In contrast, for OS, nivolumab plus ipilimumab (HR OS: 0.39), nivolumab (HR OS: 0.46) and pembrolizumab (HR OS: 0.50) were more favourable than dabrafenib plus trametinib (HR OS: 0.55) and vemurafenib plus cobimetinib (HR OS: 0.57).

CONCLUSIONS

Our NMA identified the most effective treatment options for advanced melanoma and provided valuable insights into each novel treatment's relative effectiveness and safety. This information may facilitate evidence-based decision-making and may support the optimisation of treatment and outcomes in everyday clinical practice.