Meta-analysis in epidemiology, with special reference to studies of the association between exposure to environmental tobacco smoke and lung cancer: a critique

Clinical Outcomes After Stereotactic Body Radiation Therapy for Nonspinal Bone Metastases: A Systematic Review and Meta-analysis

There are limited data available on clinical outcomes after stereotactic body radiation therapy (SBRT) for nonspinal bone metastases. We performed a systematic review and meta-analysis to characterize local control (LC), overall survival (OS), pain response rates, and toxicity after SBRT. The primary outcomes were 1-year LC, incidence of acute and late grade 3 to 5 toxicities, and overall pain response rate at 3 months. The secondary outcome was 1-year OS. The Newcastle-Ottawa scale was used for assessment of study bias, with a median score of 5 for included studies (range, 4-8). Weighted random-effects meta-analyses were conducted to estimate effect sizes. We identified 528 patients with 597 nonspinal bone lesions in 9 studies (1 prospective study and 8 retrospective observational studies) treated with SBRT. The estimated 1-year LC rate was 94.6% (95% CI, 87.0%-99.0%). The estimated 3-month combined partial and complete pain response rate after SBRT was 87.7% (95% CI, 55.1%-100.0%). The estimated combined acute and late grade 3 to 5 toxicity rate was 0.5% (95% CI, 0%-5.0%), with an estimated pathologic fracture rate of 3.1% (95% CI, 0.2%-9.1%). The estimated 1-year OS rate was 71.0% (95% CI, 51.7%-87.0%). SBRT results in excellent LC and palliation of symptoms with minimal related toxicity. Prospective investigations are warranted to further characterize long-term outcomes of SBRT for patients with nonspinal bone metastases.

Vitamin D Levels in Patients with Noninfectious Uveitis: A Systematic Review and Meta-Analysis

PURPOSE

Vitamin D deficiency has been associated with higher rates of autoimmune disease, including noninfectious uveitis. This PRISMA-compliant review and meta-analysis aimed to analyze the correlation between noninfectious uveitis and vitamin D levels.

METHODS

We searched PubMed, Embase, Cochrane, and Web of Science databases for studies, published in English, assessing vitamin D levels in patients diagnosed with noninfectious uveitis. The outcomes of interest were vitamin D deficiency, vitamin D mean level, vitamin D supplementation, and smoking rates. A subgroup analysis of inactive uveitis and active uveitis was performed. The heterogeneity was assessed with Cochrane Q-test and I2 statistics; p > 0.10 and I2 > 50% were considered significant for heterogeneity. Statistical analysis was conducted using Review Manager 5.3.

RESULTS

9 studies were included in the meta-analysis comprising a total of 10 711 patients, of whom 1,368 were diagnosed with noninfectious uveitis. Patients with noninfectious uveitis had worse results regarding vitamin D deficiency when compared with the control group (OR 0.58; CI 95% 0.44 to 0.77; p = 0.0002; I2 = 61%). Patients with inactive uveitis had better results towards vitamin D deficiency when compared with active uveitis (OR 5.00; CI 95% 2.84 to 8.81; p < 0.001; I2 = 0%).

CONCLUSION

Our research supports the increasing evidence that associates vitamin D deficiency with noninfectious uveitis and its activity. Further investigation into the efficacy of vitamin D screening and supplementation in reducing the recurrence of uveitis is necessary.

Evidence relating cigarettes, cigars and pipes to cardiovascular disease and stroke: Meta-analysis of recent data from three regions

BACKGROUND

More recent data are required relating to disease risk for use of various smoked products and of other products containing nicotine. Earlier we published meta-analyses of recent results for chronic obstructive pulmonary disease and lung cancer on the relative risk (RR) of current compared to never product use for cigarettes, cigars and pipes based on evidence from North America, Europe and Japan. We now report corresponding up-to-date evidence for acute myocardial infarction (AMI), ischaemic heart disease (IHD) and stroke.

AIM

To estimate, using recent data, AMI, IHD and stroke RRs by region for current smoking of cigarettes, cigars and pipes.

METHODS

Publications in English from 2015 to 2020 were considered that, based on epidemiological studies in the three regions, estimated the current smoking RR of AMI, IHD or stroke for one or more of the three products. The studies should involve at least 100 cases of stroke or cardiovascular disease (CVD), not be restricted to populations with specific medical conditions, and should be of cohort or nested case-control study design or randomized controlled trials. A literature search was conducted on MEDLINE, examining titles and abstracts initially, and then full texts. Additional papers were sought from reference lists of selected papers, reviews and meta-analyses. For each study identified, we entered the most recent available data on current smoking of each product, as well as the characteristics of the study and the RR estimates. Combined RR estimates were derived using random-effects meta-analysis for stroke and, in the case of CVD, separately for IHD and AMI. For cigarette smoking, where far more data were available, heterogeneity was studied by a wide range of factors. For cigar and pipe smoking, a more limited heterogeneity analysis was carried out. A more limited assessment of variation in risk by daily number of cigarettes smoked was also conducted. Results were compared with those from previous meta-analyses published since 2000.

RESULTS

Current cigarette smoking: Ten studies gave a random-effects RR for AMI of 2.72 [95% confidence interval (CI): 2.40-3.08], derived from 13 estimates between 1.47 and 4.72. Twenty-three studies gave an IHD RR of 2.01 (95%CI: 1.84-2.21), using 28 estimates between 0.81 and 4.30. Thirty-one studies gave a stroke RR of 1.62 (95%CI: 1.48-1.77), using 37 estimates from 0.66 to 2.91. Though heterogeneous, only two of the overall 78 RRs were below 1.0, 71 significantly (P < 0.05) exceeding 1.0. The heterogeneity was only partly explicable by the factors studied. Estimates were generally higher for females and for later-starting studies. They were significantly higher for North America than Europe for AMI, but not the other diseases. For stroke, the only endpoint with multiple Japanese studies, RRs were lower there than for Western studies. Adjustment for multiple factors tended to increase RRs. Our RR estimates and the variations by sex and region are consistent with earlier meta-analyses. RRs generally increased with amount smoked. Current cigar and pipe smoking: No AMI data were available. One North American study reported reduced IHD risk for non-exclusive cigar or pipe smoking, but considered few cases. Two North American studies found no increased stroke risk with exclusive cigar smoking, one reporting reduced risk for exclusive pipe smoking (RR 0.24, 95%CI: 0.06-0.91). The cigar results agree with an earlier review showing no clear risk increase for IHD or stroke.

CONCLUSION

Current cigarette smoking increases risk of AMI, IHD and stroke, RRs being 2.72, 2.01 and 1.62. The stroke risk is lower in Japan, no increase was seen for cigars/pipes.

Spinal cord stimulation and deep brain stimulation for disorders of consciousness: a systematic review and individual patient data analysis of 608 cases

The application of spinal cord stimulation (SCS) and deep brain stimulation (DBS) for disorders of consciousness (DoC) has been increasingly reported. However, there is no sufficient evidence to determine how effective and safe SCS and DBS are for DoC owing to various methodological limitations. We conducted a systematic review to elucidate the safety and efficacy of SCS and DBS for DoC by systematically reviewing related literature by searching PubMed, EMBASE, Medline, and Cochrane Library. Twenty eligible studies with 608 patients were included in this study. Ten studies with 508 patients reported the efficacy of SCS for DoC, and the estimated overall effectiveness rate was 37%. Five studies with 343 patients reported the efficacy of SCS for VS, and the estimated effectiveness rate was 30%. Three studies with 53 patients reported the efficacy of SCS for MCS, and the estimated effectiveness rate was 63%. Five studies with 92 patients reported the efficacy of DBS for DoC, and the estimated overall effectiveness rate was 40%. Four studies with 63 patients reported the efficacy of DBS for VS, and the estimated effectiveness rate was 26%. Three studies with 19 patients reported the efficacy of DBS for MCS, and the estimated effectiveness rate was 74%. The adverse event rate of DoC was 8.1% and 18.2% after SCS and DBS, respectively. These results suggest that SCS and DBS can be considered reasonable treatments for DoC with considerable efficacy and safety.

Evidence relating cigarette, cigar and pipe smoking to lung cancer and chronic obstructive pulmonary disease: Meta-analysis of recent data from three regions

BACKGROUND

There is a need to have up-to-date information for various diseases on the risk related to the use of different smoked products and the use of other nicotine-containing products. Here, we contribute to the information pool by presenting up-to-date quantitative evidence for North America, Europe and Japan and for both lung cancer and chronic obstructive pulmonary disease (COPD) on the relative risk (RR) relating to current vs never product use for each of the three smoked tobacco products, cigarettes, cigars and pipes.

AIM

To estimate lung cancer and COPD current smoking RRs for the three products using recent data for the three regions.

METHODS

Publications in English from 2010 to 2020 were considered that, based on epidemiological studies in the three regions, estimated the current smoking RR of lung cancer and/or COPD for one or more of the three products. The studies should involve at least 100 cases of the disease considered, not be restricted to specific lung cancer types or populations with specific medical conditions, and should be of cohort or nested case-control study design or randomized controlled trials. Literature searches were conducted on MEDLINE separately for lung cancer and for COPD, examining titles and abstracts initially, and then full texts. Additional papers were sought from reference lists of selected papers, reviews and meta-analyses. For each study identified, the most recent available data on each product were entered on current smoking, as well as on characteristics of the study and the RR estimates. Combined RR estimates were derived using random-effects meta-analysis. For cigarette smoking, where far more data were available, heterogeneity was studied by a wide range of factors. For cigar and pipe smoking, a more limited heterogeneity analysis was carried out. Results were compared with those from previous meta-analyses published since 2000.

RESULTS

Current cigarette smoking: For lung cancer, 44 studies (26 North American, 14 European, three Japanese, and one in multiple continents), gave an overall estimate of 12.14 [95% confidence interval (CI) 10.30-14.30]. The estimates were higher (heterogeneity P < 0.001) for North American (15.15, CI 12.77-17.96) and European studies (12.30, CI 9.77-15.49) than for Japanese studies (3.61, CI 2.87-4.55), consistent with previous evidence of lower RRs for Asia. RRs were higher (P < 0.05) for death (14.85, CI 11.99-18.38) than diagnosis (10.82, CI 8.61-13.60). There was some variation (P < 0.05) by study population, with higher RRs for international and regional studies than for national studies and studies of specific populations. RRs were higher in males, as previously reported, the within-study male/female ratio of RRs being 1.52 (CI 1.20-1.92). RRs did not vary significantly (P ≥ 0.05) by other factors. For COPD, RR estimates were provided by 18 studies (10 North American, seven European, and one Japanese). The overall estimate of 9.19 (CI 6.97-12.13), was based on heterogeneous data (P < 0.001), and higher than reported earlier. There was no (P > 0.1) variation by sex, region or exclusive use, but limited evidence (0.05 < P < 0.1) that RR estimates were greater where cases occurring shortly after baseline were ignored; where bronchiectasis was excluded from the COPD definition; and with greater confounder adjustment. Within-study comparisons showed adjusted RRs exceeded unadjusted RRs. Current cigar smoking: Three studies gave an overall lung cancer RR of 2.73 (CI 2.36-3.15), with no heterogeneity, lower than the 4.67 (CI 3.49-6.25) reported in an earlier review. Only one study gave COPD results, the RR (2.44, CI 0.98-6.05) being imprecise. Current pipe smoking: Four studies gave an overall lung cancer RR of 4.93 (CI 1.97-12.32), close to the 5.20 (CI 3.50-7.73) given earlier. However, the estimates were heterogeneous, with two above 10, and two below 3. Only one study gave COPD results, the RR (1.12, CI 0.29-4.40), being imprecise. For both diseases, the lower RR estimates for cigars and for pipes than for current smoking of cigarettes aligns with earlier published evidence.

CONCLUSION

Current cigarette smoking substantially increases lung cancer and COPD risk, more so in North America and Europe than Japan. Limited evidence confirms lower risks for cigars and pipes than cigarettes.

Efficacy and Safety of Stereotactic Body Radiation Therapy for Pediatric Malignancies: The LITE-SABR Systematic Review and Meta-Analysis

Purpose

Limited data are currently available on clinical outcomes after stereotactic body radiation therapy (SBRT) for pediatric and adolescent and young adult (AYA) patients with cancer. We aimed to perform a systematic review and study-level meta-analysis to characterize associated local control (LC), progression-free survival (PFS), overall survival, and toxicity after SBRT.

Methods and Materials

Relevant studies were queried using a Population, Intervention, Control, Outcomes, Study Design (PICOS)/Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)/Meta-analysis of Observational Studies in Epidemiology (MOOSE) selection criteria. Primary outcomes were 1-year and 2-year LC as well as incidence of acute and late grade 3 to 5 toxicities, with secondary outcomes of 1-year overall survival and 1-year PFS. Outcome effect sizes were estimated with weighted random effects meta-analyses. Mixed-effects weighted regression models were performed to examine potential correlations between biologically effective dose (BED₁₀), LC, and toxicity incidence.

Results

Across 9 published studies, we identified 142 pediatric and AYA patients with 217 lesions that were treated with SBRT. Estimated 1-year and 2-year LC rates were 83.5% (95% confidence interval, 70.9%-96.2%) and 74.0% (95% CI, 64.6%-83.4%), respectively, with an estimated acute and late grade 3 to 5 toxicity rate of 2.9% (95% CI, 0.4%-5.4%; all grade 3). The estimated 1-year OS and PFS rates were 75.4% (95% CI, 54.5%-96.3%) and 27.1% (95% CI, 17.3%-37.0%), respectively. On meta-regression, higher BED₁₀ was correlated with improved 2-year LC with every 10 Gy₁₀ increase in BED₁₀ associated with a 5% improvement in 2-year LC (P = .02) in sarcoma-predominant cohorts.

Conclusions

SBRT provided durable LC for pediatric and AYA patients with cancer with minimal severe toxicities. Dose escalation may result in improved LC for sarcoma-predominant cohorts without a subsequent increase in toxicity. However, further investigations with patient-level data and prospective inquiries are indicated to better define the role of SBRT based on patient and tumor-specific characteristics.

The future of sperm: a biovariability framework for understanding global sperm count trends

The past 50 years have seen heated debate in the reproductive sciences about global trends in human sperm count. In 2017, Levine and colleagues published the largest and most methodologically rigorous meta-regression analysis to date and reported that average total sperm concentration among men from 'Western' countries has decreased by 59.3% since 1973, with no sign of halting. These results reverberated in the scientific community and in public discussions about men and masculinity in the modern world, in part because of scientists' public-facing claims about the societal implications of the decline of male fertility. We find that existing research follows a set of implicit and explicit assumptions about how to measure and interpret sperm counts, which collectively form what we term the Sperm Count Decline hypothesis (SCD). Using the study by Levine and colleagues, we identify weaknesses and inconsistencies in the SCD, and propose an alternative framework to guide research on sperm count trends: the Sperm Count Biovariability hypothesis (SCB). SCB asserts that sperm count varies within a wide range, much of which can be considered non-pathological and species-typical. Knowledge about the relationship between individual and population sperm count and life-historical and ecological factors is critical to interpreting trends in average sperm counts and their relationships to health and fertility.

Assessment of vitamin D levels and adipokines mediated obesity among psychiatric patients on treatment and treatment naïve: A comparative cross-sectional study

Background and aims

Antipsychotic treatment may contribute to low vitamin D levels and have impact on direct anti-inflammatory activity such as adiponectin activity and indirect proinflammatory activity such as leptin and resistin activity. However, vitamin D levels and adipokines mediated effect on weight gain and increased adiposity are not well evaluated. This study, therefore, assessed vitamin D and adipokines-mediated obesity among Ghanaian psychiatric patients.

Methods

This comparative cross-sectional study was conducted at psychiatric unit of Komfo Anokye Teaching Hospital, Kumasi, Ghana. Anthropometric measurements, sociodemographic and previous medical history were taken from 300 antipsychotics treatment naïve and active patients. Obesity was classified using World Health Organization (WHO) body mass index (BMI)-specific cut-offs. Blood samples were collected for serum vitamin D and adipokines (adiponectin, leptin, and resistin) analysis using enzyme-linked immunosorbent assay. Statistical analyses were done using SPSS version 26.0 and GraphPad Prism version 8.0.

Results

We observed higher prevalence of obesity among treatment active psychiatric patients (40.7%) compared to treatment naïve group (16.8%). Vitamin D insufficiency and deficiency prevalence were significantly higher among the treatment active group (25.3%; 39.5%; p < 0.001) and associated with increased odds of obesity (91.8%; cOR = 91.84, 95% confidence interval [CI]: 24.94-338.13). Moreover, adiponectin (84.2%: cOR = 14.15, 95% CI: 5.52-36.27), leptin (55.6% cOR = 2.20, 95% CI: 1.04-4.67), and resistin (79.4%: cOR = -8.34, 95% CI: 3.39-20.55) were significantly associated with increased odds of obesity among treatment active psychiatric. Furthermore, treatment active psychiatric patients exhibited inverse correlation for adiponectin and leptin with BMI (r = -0.62; -0.24), and WHtR (r = -0.53; -0.24); however, a moderate positive correlation for resistin with BMI (r = 0.80), HC (r = 0.67), and WHtR (r = 0.65).

Conclusion

Obesity is more prevalent in psychiatric patients on antipsychotics such as Olanzapine and Clozapine. Obesity among treatment active psychiatric patients is associated with vitamin D insufficiency and deficiency, low adiponectin and leptin levels but higher resistin level.

Research features between Urology and Nephrology authors in articles regarding UTI related to CKD, HD, PD, and renal transplantation

BACKGROUND

A urinary tract infection (UTI) is one of the most common types of infections affecting the urinary tract. When bacteria enter the bladder or kidney and multiply in the urine, a URI can occur. The urethra is shorter in women than in men, which makes it easier for bacteria to reach the bladder or kidneys and cause infection. A comparison of the research differences between Urology and Nephrology (UN) authors regarding UTI pertaining to the 4 areas (i.e., Chronic Kidney Disease, Hemodialysis, Peritoneal Dialysis, and Renal Transplantation [CHPR]) is thus necessary. We propose and verify 2 hypotheses: CHPR-related articles on UTI have equal journal impact factors (JIFs) in research achievements (RAs) and UN authors have similar research features (RFs).

METHODS

Based on keywords associated with UTI and CHPR in titles, subject areas, and abstracts since 2013, we obtained 1284 abstracts and their associated metadata (e.g., citations, authors, research institutes, departments, countries of origin) from the Web of Science core collection. There were 1030 corresponding and first (co-first) authors with hT-JIF-indices (i.e., JIF was computed using hT-index rather than citations as usual). The following 5 visualizations were used to present the author's RA: radar, Sankey, time-to-event, impact beam plot, and choropleth map. The forest plot was used to distinguish RFs by observing the proportional counts of keyword plus in Web of Science core collection between UN authors.

RESULTS

It was observed that CHPR-related articles had unequal JIFs (χ2 = 13.08, P = .004, df = 3, n = 1030) and UN departments had different RFs (Q = 53.24, df = 29, P = .004). In terms of countries, institutes, departments, and authors, the United States (hT-JIF = 38.30), Mayo Clinic (12.9), Nephrology (19.14), and Diana Karpman (10.34) from Sweden had the highest hT-JIF index.

CONCLUSION

With the aid of visualizations, the hT-JIF-index and keyword plus were demonstrated to assess RAs and distinguish RFs between UN authors. A replication of this study under other topics and in other disciplines is recommended in the future, rather than limiting it to UN authors only, as we did in this study.

Use of folic acid supplementation to halt and even reverse the progression of gastric precancerous conditions: a meta-analysis

Background

Current data indicate that supplements such as folic acid and vitamin B may be beneficial in halting and even reversing atrophic gastritis, intestinal metaplasia and intraepithelial neoplasia, generally referred to as gastric precancerous conditions(GPC). However, there is no Meta-analysis article to evaluate the prevention and treatment of folic acid in the gastric precancerous conditions. We therefore conducted a meta-analysis to confirm the efficacy of folic acid in treating GPC.

Methods

Using a systematic review method, consider randomized controlled trials (RCT), including clinical trial reports, unpublished clinical trial data, and conference papers. The search time was been set from the database’s establishment to June 2, 2021. The language was not limited, using PubMed, SinoMed, Lancet, Web of Science, CNKI, Cochrane, Ovid, Science Direct, Embase, and EBSCO databases. Data were extracted using a pre-designed extraction tool and analysis was undertaken using RevMan5.2.Besides,we use Origin software to construct the Time-dose interval analysis.

Results

Of the 225 records identified, 13 studies involving 1252 patients (including 11 clinical controlled trials, 1 conference paper report and 1 unpublished research report) met the inclusion conditions. Folic acid dose maintained at 20–30 mg / d for 3–6 months may be beneficial to pathological changes of GPC. Moreover, in the 3 month treatment of 5 trials, the effect was more obvious when the folic acid dose was maintained at 30 mg / d. In the 7 trials, the symptom ineffective rate of GPC treated with folic acid was 32% (RR:0.32, 95% confidence interval CI:0.21–0.48), which was combined using a fixed analysis model; The effect of folic acid on gastric mucosal atrophy in 5 trials (RR: 1.61, 95%CI 1.07–2.41). The changes of folic acid on intestinal metaplasia in the 2 experiments (RR: 1.77, 95% CI: 1.32–2.37).The 2 results are combined using a fixed analytical model. However, the subgroup analysis of 9 trials revealed no significant effectiveness of symptom.

Conclusions

Our research showed that folic acid supplementation brings benefits in preventing and even reversing the progression of GPC in the stomach, and provided evidence for its potential clinical use in management of GPC.

Registration: The logn number of our Meta-anlysis on PROSPERO is CRD420223062.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-022-02390-y.

Stereotactic Body Radiation Therapy versus Conventional External Beam Radiation Therapy for Painful Bone Metastases: A Systematic Review and Meta-analysis of Randomized Trials

PURPOSE

To compare the efficacy and safety of stereotactic body radiation therapy (SBRT) and conventional external beam radiation therapy (cEBRT) in patients with previously unirradiated painful bone metastases (BM).

METHODS

We searched biomedical databases for eligible randomized trials (RCTs). The outcomes of interest were pain response, local progression, overall survival (OS) and adverse events. We used established tools to assess the quality of the individual trials and certainty of the pooled evidence. We performed meta-analyses using random effects models.

RESULTS

Six RCTs were identified. SBRT improved complete pain response rates at 3 months (OR, 3.38; 95% CI, 1.88-6.07; high certainty), reduced local progression rates (OR, 0.19; 95% CI, 0.06-0.62; high certainty) and increase pain flare rates. There were no differences for other outcomes.

CONCLUSION

Among patients with previously unirradiated painful BM, SBRT significantly improved complete pain response rates at 3 months, delayed local progression and increase pain flare rates.

Using the forest plot to compare citation achievements in bibliographic and meta-analysis studies since 2011 using data on PubMed Central: A retrospective study

BACKGROUND

We saw a steady increase in the number of bibliographic studies published over the years. The reason for this rise is attributed to the better accessibility of bibliographic data and software packages that specialize in bibliographic analyses. Any difference in citation achievements between bibliographic and meta-analysis studies observed so far need to be verified. In this study, we aimed to identify the frequently observed MeSH terms in these 2 types of study and investigate whether the highlighted MeSH terms are strongly associated with one of the study types.

METHODS

By searching the PubMed Central database, 5121 articles relevant to bibliometric and meta-analysis studies were downloaded since 2011. Social network analysis was applied to highlight the major MeSH terms of quantitative and statistical methods in these 2 types of studies. MeSH terms were then individually tested for any differences in event counts over the years between study types using odds of 95% confidence intervals for comparison.

RESULTS

In these 2 studies, we found that the most productive countries were the United States (19.9%), followed by the United Kingdom (8.8%) and China (8.7%); the most number of articles were published in PLoS One (2.9%), Stat Med (2.5%), and Res Synth (2.4%); and the most frequently observed MeSH terms were statistics and numerical data in bibliographic studies and methods in meta-analysis. Differences were found when compared to the event counts and the citation achievements in these 2 study types.

CONCLUSION

The breakthrough was made by developing a dashboard using forest plots to display the difference in event counts. The visualization of the observed MeSH terms could be replicated for future academic pursuits and applications in other disciplines using the odds of 95% confidence intervals.

Stereotactic Radiosurgery for Dural Arteriovenous Fistulas: A Systematic Review and Meta-Analysis and International Stereotactic Radiosurgery Society Practice Guidelines

BACKGROUND

Dural arteriovenous fistulas (dAVFs) are often treated with stereotactic radiosurgery (SRS) to achieve complete obliteration (CO), prevent future hemorrhages, and ameliorate neurological symptoms.

OBJECTIVE

To summarize outcomes after SRS for dAVFs and propose relevant practice recommendations.

METHODS

Using a PICOS/PRISMA/MOOSE protocol, we included patients with dAVFs treated with SRS and data for at least one of the outcomes of the study. Relevant outcomes were CO, symptom improvement and cure, and post-SRS hemorrhage or permanent neurological deficits (PNDs). Estimated outcome effect sizes were determined using weighted random-effects meta-analyses using DerSimonian and Laird methods. To assess potential relationships between patient and lesion characteristics and clinical outcomes, mixed-effects weighted regression models were used.

RESULTS

Across 21 published studies, we identified 705 patients with 721 dAVFs treated with SRS. The CO rate was 68.6% (95% CI 60.7%-76.5%) with symptom improvement and cure rates of 97.2% (95% CI 93.2%-100%) and 78.8% (95% CI 69.3%-88.2%), respectively. Estimated incidences of post-SRS hemorrhage and PNDs were 1.1% (95% CI 0.6%-1.6%) and 1.3% (95% CI 0.8%-1.8%), respectively. Noncavernous sinus (NCS) dAVFs were associated with lower CO (P = .03) and symptom cure rates (P = .001). Higher grade was also associated with lower symptom cure rates (P = .04), whereas previous embolization was associated with higher symptom cure rates (P = .01).

CONCLUSION

SRS for dAVFs results in CO in the majority of patients with excellent symptom improvement rates with minimal toxicity. Patients with NCS and/or higher-grade dAVFs have poorer symptom cure rates. Combined therapy with embolization and SRS is recommended when feasible for clinically aggressive dAVFs or those refractory to embolization to maximize the likelihood of symptom cure.

Review with meta-analysis relating North American, European and Japanese snus or smokeless tobacco use to major smoking-related diseases

BACKGROUND

While extensive information exists relating cigarette smoking to the risk of lung cancer, chronic obstructive pulmonary disease (COPD), ischaemic heart disease (IHD) or acute myocardial infarction (AMI), and stroke, far less information is available on risks from moist snuff (“snus”) or smokeless tobacco (ST) in United States/Canada, Europe or Japan.

AIM

To summarize data from the selected countries on risks of the four diseases associated with current ST or snus use.

METHODS

Publications in English in 1990-2020 were considered that, based on epidemiological studies in North America, Europe or Japan, estimated risks of lung cancer, COPD, IHD/AMI, or stroke according to use of ST or snus. The studies should involve at least 100 cases of the disease considered, and not be restricted to those with specific other diseases. Medline literature searches were conducted, selecting papers initially from examination of titles and abstracts, and then from full texts. Further papers were sought from reference lists in selected papers, reviews and meta-analyses. For each disease, relative risk estimates adjusted at least for age were extracted relating ST or snus use to risk, and combined using random-effects meta-analysis. The estimates were mainly for current vs. never or non-current use, but results for ever vs never use were also considered.

RESULTS

Seven publications reported results for ST use from six United States studies. The most useful results came from four studies which provided results for current vs. never use. Random-effects meta-analyses of these results showed an increased risk for each disease, clearest for lung cancer (relative risk 1.59, 95% confidence interval 1.06-2.39, based on 4 estimates) and COPD (1.57, 1.09-2.26, n = 3), but also significant (at P < 0.05) for IHD (1.26, 1.10-1.45, n = 4) and stroke (1.27, 1.03-1.57, n = 4). Also including results for ever vs. never use from two other studies increased the lung cancer estimate to 1.80 (1.23-2.64, n = 6), but had little effect on the other estimates. For snus, 16 publications described results from 12 studies, one in Norway and the rest in Sweden. There were no results for COPD, and only three for lung cancer, with these reporting a relative risk of 0.80 (0.40-1.30) for current vs never use. More extensive data were available for IHD/AMI and stroke. Using the latest results from each study, combined estimates for current vs. never use were 1.00 (0.91-1.11, n = 5) for IHD/AMI and 1.05 (0.95-1.17, n = 2) for stroke, while for current vs. non-current use they were 1.10 (0.92-1.33, n = 9) for IHD/AMI and 1.12 (0.86-1.45, n = 9) for stroke. Meta-analyses including earlier results from some studies also showed no significant association between snus use and IHD/AMI or stroke. No relevant results were found for Japan.

CONCLUSION

Risks of smoking-related diseases from snus use in Scandinavia are not demonstrated, while those from ST use in the United States are less than from smoking.

Survival rates and safety associated with chemoradiotherapy followed by surgery and chemoradiotherapy alone for patients with T4 esophageal cancer: a systematic review and meta-analysis

BACKGROUND

The optimal treatment approach for T4 esophageal cancer is not well established. We aimed to perform a systematic review and meta-analysis to determine the survival rates and safety of chemoradiotherapy followed by surgery (CRT-S) and chemoradiotherapy alone (CRT) in patients with T4 N_any M0 esophageal cancer.

MATERIALS AND METHODS

We searched databases for eligible prospective or retrospective studies. The outcomes of interest were overall survival (OS) at 1, 3 and 5 years, treatment-related fistula formation and mortality rates. Meta-analyses were performed using the random effects models separately for studies evaluating CRT-S and CRT. Subgroup analyses were performed based on histology, radiation dose, chemotherapy regimen and duration of the interval between CRT and surgery.

RESULTS

We identified 23 studies including 1,119 patients with predominantly squamous cell carcinoma (93%) and adenocarcinoma (3%) histology. The OS rates of patients receiving CRT-S were 65%, 36% and 20% at 1, 3 and 5 years, respectively. The OS rates of patients receiving CRT were 30%, 11% and 10% at 1, 3 and 5 years, respectively. Treatment-related fistula formation rates were 4% for CRT-S and 9% for CRT. Treatment-related mortality rates were 3% for both groups. Subgroup analyses showed that the interval of >2 months between CRT and surgery was associated with significantly improved OS rates at 1, 3 and 5 years.

CONCLUSION

Chemoradiotherapy is an efficacious treatment approach for T4 esophageal cancer, with clinically acceptable rates of treatment-related fistula formation and mortality. Tri-modality approach with surgery can be considered in carefully selected patients. Our study findings should be interpreted with caution due to the lack of high-quality evidence. Randomized controlled trials are warranted to confirm these findings.

Radiotherapy and Radiosurgery in the Management of Optic Nerve Sheath Meningiomas: An International Systematic Review and Meta-Analysis of Twenty Studies

BACKGROUND

Optic nerve sheath meningiomas (ONMs) are often managed with radiotherapy (RT) with the goal of achieving radiographic local control (LC) and preventing deterioration of visual acuity (VA). We aimed to perform a systematic review and meta-analysis of outcomes for patients with ONM treated with RT.

METHODS

The PICOS/PRISMA/MOOSE selection criteria were used to identify studies. Primary outcomes were stable or improved VA and radiographic LC at last follow-up. The secondary outcomes were incidences of radiation-induced retinopathy and xerophthalmia and stable or improved visual fields (VFs). Weighted random-effects meta-analyses using the DerSimonian and Laird methods were conducted to characterize effect sizes. Mixed-effects regression models were used to examine potential correlations between gross tumor volume (GTV) and outcomes.

RESULTS

In total, 444 patients with ONM across 20 published studies were included. The estimated LC rate was 99.8% (95% confidence interval [CI], 98.3%-100%), and the estimated proportion of patients with stable or improved VA or VF was 89.7% (95% CI, 86.2%-92.4%) and 93.3% (95% CI, 89.5%-95.8%), respectively. Estimated incidences of radiation-induced retinopathy and xerophthalmia were 7.2% and 10.1%, respectively. GTV was significantly associated with VA (P = 0.014) with estimated VA rates of 96.4%, 91.4%, and 80.5% for GTVs of 2.0, 3.0, and 4.0 cm³, respectively.

CONCLUSIONS

RT was well tolerated, with excellent LC achieved. Nearly 90% of patients noted either stability or improvement in VA and VF. Larger ONMs were associated with poorer VA.

Adjuvant radiotherapy may not significantly change outcomes in high-risk cutaneous squamous cell carcinomas with clear surgical margins: A systematic review and meta-analysis

BACKGROUND

The role of adjuvant radiotherapy for high-risk cutaneous squamous cell carcinomas (cSCC) after surgery with negative margins is unclear.

OBJECTIVE

To conduct a systematic review and meta-analysis examining the risk of poor outcomes for those treated with surgery vs. surgery and adjuvant radiotherapy.

METHODS

A comprehensive search of articles was executed in PubMed, Embase, and Cochrane Database. Random-effected meta-analyses were conducted.

RESULTS

Thirty-three studies comprised of 3,867 high-risk cSCC were included. There were no statistically significant differences in poor outcomes between the surgery vs. surgery and adjuvant radiotherapy groups. Estimates for local recurrence were 15.2% (95% confidence interval [CI]: 6.3%-27%) vs. 8.8% (CI: 1.6%-20.9%), regional metastases were 11.5% (CI: 7.2%-16.7%) vs. 4.4% (CI: 0%-18%), distant metastases were 2.6% (CI: 0.6%-6%) vs. 1.7% (CI: 0.2%-4.5%) and disease-specific deaths were 8.2% (CI: 1.2%-20.6%) vs. 19.7% (CI: 3.8%-43.7%) for the surgery group vs. surgery and adjuvant radiotherapy group respectively.

LIMITATIONS

Retrospective nature of most studies with a lack of sufficient patient-specific data.

CONCLUSIONS

For patients with high risk cSCC treated with margin-negative resection, there were no differences in poor outcomes between the surgery vs. surgery and adjuvant radiotherapy groups. Randomized-controlled trials are necessary to define the benefit of adjuvant radiotherapy in this setting.

Systematic review with meta-analysis of the epidemiological evidence in Europe, Israel, America and Australasia on smoking and COVID-19

BACKGROUND

Previous meta-analyses related smoking to death or severe infection from coronavirus disease 2019 (COVID-19) in hospitalized patients, but considered only a few studies, did not adjust for demographics and comorbidities, and inadequately defined smoking.

AIM

To review and meta-analyse epidemiological evidence on smoking and COVID-19, considering a range of endpoints, populations and smoking definitions and the effect of adjustment.

METHODS

Studies were identified from publications in English up to 30 September, 2020 involving at least 100 individuals, carried out in Europe, Israel, America or Australasia, not restricted to those with specific other diseases, and providing information relating smoking to various COVID-related endpoints. Meta-analyses were carried out for combinations of population and endpoint, with variation studied by smoking definition, adjustment level and other factors.

RESULTS

From 96 publications, 74 studies were identified, 37 in the United States, 10 in the United Kingdom, with up to four in the other countries. Three involved over a million individuals, and 37 involved less than a thousand. Adjusted results for smoking were available in 42 studies, with adjustment not considered in 20 studies. Results were considered by endpoint. No significant effect of smoking on COVID-19 positivity was seen in the general population, but there was a reduced risk in those tested. Best-adjusted estimates for current (vs never) smoking were 0.87 (95% confidence interval: 0.52-1.47) in the general population and 0.52 (0.43-0.64) in those tested. For those hospitalized due to COVID-19, unadjusted rates were significantly increased in current smokers (1.20, 1.01-1.42) and ever smokers (1.64, 1.41-1.91), but those adjusted for comorbidities showed no increase for current (0.82, 0.52-1.30) or ever smokers (1.00, 0.76-1.32). There was little evidence to suggest that smoking was associated with intensive care admission. For those hospitalized with COVID-19, best-adjusted estimates were 0.88 (0.72-1.08) for current smokers and 1.10 (0.99-1.22) for ever smokers. In those hospitalized with COVID-19, smoking was not significantly related to subsequent mechanical ventilation, with best-adjusted estimates of 1.12 (0.60-2.09) for current smokers and 1.05 (0.88-1.25) for ever smokers. For those hospitalized with severe COVID-19, best-adjusted estimates were 0.74 (0.49-1.12) for current smokers and 1.15 (0.87-1.51) for ever smokers; few estimates were adjusted for comorbidities. While smoking was associated with increased mortality in unadjusted analyses, the association disappeared after adjustment for comorbidities. For example, in those hospitalized with COVID-19, the unadjusted estimate for ever smokers of 1.59 (1.37-1.83) reduced to 1.07 (0.82-1.38) when adjusted for comorbidities. Studies on those with severe COVID-19 showed that smoking tended to be associated with worsening of the disease. However, no estimate was adjusted, even for demographics. Estimates did not clearly vary by location or study size, and there was too little evidence to usefully study variations by age, amount smoked or years quit.

CONCLUSION

The increased COVID-19 death rate in smokers seen in unadjusted analyses disappears following adjustment for demographics and comorbidities. Among those tested, smoking is associated with lower COVID-19 infection rates.

Bias Assessment in Outcomes Research: The Role of Relative Versus Absolute Approaches

OBJECTIVES

Bias assessment tools vary in content and detail, and the method used for assessment may produce different assessment results in a study if not carefully considered. Therefore, taking an approach to the assessment of studies that produces a similar result regardless of the tool used for assessment (tool independence) is important.

METHODS

A preexisting study that used 25 different quality scales was assessed to examine tool dependence of 2 common approaches to bias assessments-absolute value judgments (defined as the qualitative risk of bias judgment based on a threshold across studies) and relative ranks (defined as the relative probability toward bias of a study relative to the best assessed study). Agreement between each of the 25 scales and a composite scale (that includes all unique safeguards across all scales) was computed (using the intraclass correlation coefficient [ICC]; consistency). Tool dependence was considered present when the ICCs were inconsistent across the 25 scales for the same study.

RESULTS

We found that using relative ranks for tools with different numbers and types of items produced consistent results, with only small differences in the agreement for the various tools with the composite tool, whereas consistency (measured by the ICC) varied considerably when using absolute judgments. Inconsistency is problematic because it means that the assessment result is linked to the scale and not to the study.

CONCLUSIONS

Tool independence is an important attribute of a bias assessment tool. On the basis of this study, the use of relative ranks retains tool independence and therefore produces consistent ranks for the same study across tools.

Prehabilitation exercise therapy for cancer: A systematic review and meta-analysis

OBJECTIVE

The purpose of this study was to determine the impact of prehabilitation exercise intervention with respect to (1) acceptability, feasibility, and safety; and (2) physical function, measured by 6-minute-walk test (6MWT).

DATA SOURCES

PRISMA guidelines were used to systematically search PubMed, Embase, and CINAHL databases evaluating prehabilitation exercise interventions.

STUDY SELECTION

The inclusion criteria were studies investigating patients who underwent surgery for their cancer and underwent prehabilitation exercise.

DATA EXTRACTION AND SYNTHESIS

Guidelines were applied by independent extraction by multiple observers. Data were pooled using a random-effects model.

MAIN OUTCOME(S) AND MEASURE(S)

Acceptability, feasibility, and safety rates were calculated. 6MWT (maximum distance a person can walk at their own pace on a hard, flat surface, measured in meters, with longer distance indicative of better performance status) was compared using two arms using the DerSimonian and Laird method.

RESULTS

Objective 1. Across 21 studies included in this review, 1564 patients were enrolled, 1371 (87.7%) accepted the trial; of 1371, 1230 (89.7% feasibility) completed the intervention. There was no grade 3+ toxicities. Objective 2. Meta-analysis of five studies demonstrated a statistically significant decrease in 6MWT distance postoperatively in the control group (mean difference = +27.9 m; 95% confidence interval (CI): 9.3; 46.6) and a significant improvement postoperatively in the prehabilitation group (mean difference = -24.1 m; 95% CI: -45.7; -2.6). Meta-analysis demonstrated improvements in 6MWT distance 4-8 weeks postoperatively in the prehabilitation group compared to the control group (mean difference = -58.0 m, 95% CI: -92.8; -23.3).

CONCLUSIONS AND RELEVANCE

Prehabilitation exercise for cancer patients undergoing surgery was found to be safe, acceptable, and feasible with a statistically significant improvement in the 6MWT, indicating that prehabilitation can improve postoperative functional capacity.

Radiotherapy and Receptor Tyrosine Kinase Inhibition for Solid Cancers (ROCKIT): A Meta-Analysis of 13 Studies

Background

We hypothesized that the addition of receptor tyrosine kinase inhibitors (RTKis, e.g., lapatinib, erlotinib, cetuximab, bevacizumab, panitumumab) to radiotherapy-based treatment for solid tumors does not increase overall survival but may increase toxicity.

Methods

Population, Intervention, Control, Outcome, Study Design; Preferred Reporting Items for Systematic Reviews and Meta-Analyses; and Meta-analysis of Observational Studies in Epidemiology methods were used to identify prospective randomized studies including patients with solid tumor cancers treated with radiotherapy with or without RTKis. Extracted variables included use of radiotherapy vs chemoradiotherapy, RTKi type (antibody vs small molecule), outcomes, and toxicities. The primary endpoint was overall survival; the secondary endpoint was grade 3+ toxicity. Random-effects meta-analyses were performed for each outcome measure. All statistical tests were 2-sided.

Results

A total of 405 studies met the initial search criteria, of which 13 prospective randomized trials of radiotherapy with or without RTKi met the inclusion criteria, encompassing 5678 patients. The trials included cancers of the head and neck (6 trials, 3295 patients), esophagus (3 trials, 762 patients), lung (2 trials, 550 patients), and brain (2 trials, 1542 patients). Three studies evaluated a small molecule and radiotherapy in 949 patients, and 10 studies evaluated antibodies and radiotherapy in 4729 patients. The addition of RTKis to radiotherapy-based treatment did not improve overall survival (hazard ratio = 1.02, 95% confidence interval = 0.90 to 1.15, P = .76) but increased grade 3+ toxicity (relative risk = 1.18, 95% confidence interval = 1.06 to 1.33, P = .009).

Conclusions

The addition of RTKis to radiotherapy does not improve survival and worsens toxicity.

Dose Escalated Radiation Therapy for Glioblastoma Multiforme: An International Systematic Review and Meta-Analysis of 22 Prospective Trials

PURPOSE

Limited evidence is available on the utility of dose-escalated radiation therapy (DE-RT) with or without temozolomide (TMZ) versus standard-of-care radiation therapy (SoC-RT) for patients with newly diagnosed glioblastoma multiforme. We performed a systematic review/meta-analysis to compare overall survival (OS) and progression-free survival (PFS) between DE-RT and SoC-RT.

METHODS AND MATERIALS

We used a Population, Intervention, Control, Outcomes, Study Design/Preferred Reporting Items for Systematic Reviews and Meta-analyses/Meta-analysis of Observational Studies in Epidemiology selection criterion to identify studies. The primary and secondary outcomes were 1-year OS and 1-year PFS, respectively. Outcomes and comparisons were subdivided based on receipt of TMZ and MGMT status. DE-RT was defined based on equivalent dose calculations. Random effects meta-analyses using the Knapp-Hartung correction, arcsine transformation, and restricted maximum likelihood method were conducted. Meta-regression was used to compare therapeutic (eg, DE-RT or TMZ) and pathologic characteristics (eg, MGMT methylation status) using the Wald-type test.

RESULTS

Across 22 published studies, 2198 patients with glioblastoma multiforme were included; 507 received DE-RT. One-year OS after DE-RT alone was higher than SoC-RT alone (46.3% vs 23.4%; P = .02) as was 1-year PFS (17.9% vs 5.3%; P = .02). No significant difference in 1-year OS (73.2% vs 64.4%; P = .23) or 1-year PFS (44.5% vs 44.3%; P = .33) between DE-RT + TMZ and SoC-RT + TMZ was noted. No difference in 1-year OS was noted between DE-RT + TMZ and SoC-RT + TMZ in either MGMT methylated (83.2% vs 73.2%; P = .23) or MGMT unmethylated (72.6% vs 50.6%; P = .16) patients.

CONCLUSIONS

DE-RT alone resulted in superior PFS and OS versus SoC-RT alone. DE-RT + TMZ did not lead to improved outcomes versus SoC-RT + TMZ. No differential benefit based on MGMT status was found. Future studies are warranted to define which subgroups benefit most from DE-RT.

Systematic review and meta-analysis of breast cancer brain metastasis and primary tumor receptor expression discordance

Background

Change in hormone receptor (estrogen [ER] and progesterone [PR]) and/or human epidermal growth factor receptor type 2 (HER2) status during the evolutionary course of metastatic breast cancer and the effect of tumor classification subtype switching remain understudied and underappreciated in brain metastasis patients.

Methods

Using preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines, a systematic review of series published prior to April 2020 obtained from the Medline database of biopsied or resected breast cancer brain metastasis (BCBM) was performed. Weighted random effects models were used to calculate pooled estimates.

Results

15 full-text articles were included with receptor expression analyses on 1373 patients who underwent biopsy or resection of at least one intracranial lesion to compare to the primary tumor. Primary tumor receptor expression immunophenotypes were 45.0% ER+, 41.0% ER−, 31.0% PR+, 51.0% PR−, 35% HER2+, and 47.0% HER2−. Corresponding BCBM immunophenotypes were 19.0% ER+, 31.0% ER−, 13.0% PR+, 40.0% PR−, 21.0% HER2+, and 26.0% HER2−. On primary/BCBM comparison, 540 patients (42.6%) exhibited discordance in any receptor with 17.0% (95% CI: 13.0%–23.0%) discordant on ER, 23.0% (95% CI: 18.0%–30.0%) discordant on PR, and 12.0% (95% CI: 8.0%–16.0%) discordant on HER2 status. The most common receptor conversions found in BCBM were ER loss 11.0% (95% CI: 8.0%–16.0%), PR loss 15.0% (95% CI: 11.0%–21.0%), and HER2 gain 9.0% (95% CI: 7.0%–11.0%).

Conclusions

BCBM exhibits significant receptor expression discordance in comparison to primary tumors in approximately 40% of patients. Classification patterns need to be analyzed to determine factors predictive of BCBM/primary tumor discordance. Overall, tumor subtype switching and its effect on clinical management remains underappreciated.

Fat compartments in patients with depression: A meta-analysis

INTRODUCTION

Depressive disorders are a common illness worldwide. Major depression is known as a significant predictor of the metabolic syndrome. However, the effects of depression on adipose tissue compartments are controversial. This meta-analysis aimed to evaluate the state of research on the relationship between patients with depression and adipose tissue compartments as compared to nondepressed individuals.

METHODS

The PubMed database was searched for human studies that measured adipose tissue compartments such as visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT) and/or organ-specific adipose tissue measurements using dual-energy X-ray absorptiometry, magnetic resonance imaging or computed tomography scan and reported the means and a measure of variance separately for depressed individuals and healthy controls. Twelve articles were identified, including a total of 1,141 depressed and 2,545 nondepressed individuals.

RESULTS

Major depressive disorder and self-reported depressive symptoms were associated with elevated visceral adipose tissue and elevated subcutaneous adipose tissue. Subanalyses for gender, age, method of adipose tissue measurement, and method of depression assessment showed elevated visceral adipose in depressed individuals. The results could be replicated when focussing on studies controlling for body mass index (BMI). Regarding other adipose tissue compartments, meta-analysis could not be carried out due to lack of studies.

CONCLUSIONS

Depression is associated with enlarged visceral and subcutaneous adipose tissue. Further, especially longitudinal, research is needed to identify the mechanism through which depressive disorders contribute to visceral adiposity.

Safety and Survival Rates Associated With Ablative Stereotactic Radiotherapy for Patients With Oligometastatic Cancer: A Systematic Review and Meta-analysis

Importance

The oligometastatic paradigm postulates that patients with a limited number of metastases can be treated with ablative local therapy to each site of disease with curative intent. Stereotactic ablative radiotherapy (SABR) is a radiation technique that has become widely used in this setting. However, prospective data are limited and are mainly from single institutional studies.

Objective

To conduct a meta-analysis to characterize the safety and clinical benefit of SABR in oligometastatic cancer.

Data Sources

A comprehensive search was conducted in PubMed/MEDLINE, Embase, Cochrane Database of Systematic Reviews, and Cumulative Index to Nursing and Allied Health Literature on December 23, 2019, that included prospective clinical trials and review articles that were published within the past 15 years.

Study Selection

Inclusion criteria were single-arm or multiarm prospective trials including patients with oligometastatic cancer (ie, ≤5 sites of extracranial disease), and SABR was administered in less than or equal to 8 fractions with greater than or equal to 5 Gy/fraction.

Data Extraction and Synthesis

The Population, Intervention, Control, Outcomes and Study Design; Preferred Reporting Items for Systematic Reviews and Meta-analyses; and Meta-analysis of Observational Studies in Epidemiology methods were used to identify eligible studies. Study eligibility and data extraction were reviewed by 3 authors independently. Random-effects meta-analyses using the Knapp-Hartung correction, arcsine transformation, and restricted maximum likelihood method were conducted.

Main Outcomes and Measures

Safety (acute and late grade 3-5 toxic effects) and clinical benefit (1-year local control, 1-year overall survival, and 1-year progression-free survival).

Results

Twenty-one studies comprising 943 patients and 1290 oligometastases were included. Median age was 63.8 years (interquartile range, 59.6-66.1 years) and median follow-up was 16.9 months (interquartile range, 13.7-24.5 months). The most common primary sites were prostate (22.9%), colorectal (16.6%), breast (13.1%), and lung (12.8%). The estimate for acute grade 3 to 5 toxic effect rates under the random-effects models was 1.2% (95% CI, 0%-3.8%; I2 = 50%; 95% CI, 3%-74%; and τ = 0.20%; 95% CI, 0.00%-1.43%), and the estimate for late grade 3 to 5 toxic effects was 1.7% (95% CI, 0.2%-4.6%; I2 = 54%; 95% CI, 11%-76%; and τ = 0.25%; 0.01%-1.00%). The random-effects estimate for 1-year local control was 94.7% (95% CI, 88.6%-98.6%; I2 = 90%; 95% CI, 86%-94%; and τ = 0.81%; 95% CI, 0.36%-2.38%]). The estimate for 1-year overall survival was 85.4% (95% CI, 77.1%-92.0%; I2 = 82%; 95% CI, 71%-88%; and τ = 0.72%; 95% CI, 0.30%-2.09%) and 51.4% (95% CI, 42.7%-60.1%; I2 = 58%; 95% CI, 17%-78%; and τ = 0.20%; 95% CI, 0.02%-1.21%) for 1-year progression-free survival.

Conclusions and Relevance

In this meta-analysis, SABR appears to be relatively safe in patients with oligometastatic cancer with clinically acceptable rates of acute and late grade 3 to 5 toxic effects less than 13% and with clinically acceptable rates of 1-year local control overall survival, and progression-free survival. These findings are hypothesis generating and require validation by ongoing and planned prospective clinical trials.

Meta-analysis of randomized controlled trials on calcium supplements and dairy products for changes in body weight and obesity indices

This meta-analysis was performed to investigate whether calcium supplements and dairy products change obesity indices including fat mass. Original articles published in English between July 2009 and August 2019 were identified. Ten and 14 randomised controlled trials (RCTs) with ≥ 12 weeks interventions of calcium supplements and dairy products among overweight or obese adults aged ≥18 were critically reviewed. Mean difference (MD) or standardised mean difference (SMD) with 95% confidence interval (CI) were obtained using a random effect meta-analysis. Dairy products significantly changed fat mass (SMD, 95% CI; -0.40 [-0.77, -0.02]) and BMI (MD, 95% CI: -0.46 kg/m2 [-0.67, -0.26]), and calcium supplements also showed changes in fat mass (SMD, 95% CI; -0.15[-0.28, -0.02]). However, in the analysis of RCTs with low risk of bias scores, the significant changes remained only in the dairy-products intervention. Our findings suggest that dairy products without distinction of fat percentage may help reduce fat mass and BMI, but calcium supplements may not.

The Role of Postoperative Radiation Therapy for pN2 Non-small-cell Lung Cancer

BACKGROUND

The role for postoperative radiation therapy (PORT) for patients with non-small-cell lung cancer (NSCLC) with mediastinal lymph node (LN) involvement (pN2 disease) is controversial. We compared surgery alone with PORT among patients with pN2 NSCLC. We then performed subset analyses to better delineate patients that might benefit from PORT.

PATIENTS AND METHODS

We conducted a propensity score (PS)-matched, inverse probability of treatment weighting (IPTW) Surveillance, Epidemiology, and End Results (SEER) analysis of patients with pN2 disease from 1989 to 2016 with surgery alone or PORT. Multiple imputation with chained equations was used for missing LN data.

RESULTS

A total of 8631 patients were included in this analysis; 4579 underwent surgery alone, and 4052 underwent PORT. Following PS matching and IPTW, there was no difference in overall survival (OS) (hazard ratio [HR], 0.99; P = .76). However, PORT improved OS among a subset of patients with a LN positive to sampled ratio ≥ 50% (HR, 0.90; P = .01). Moreover, there was a trend towards improved OS among this subset, even with chemotherapy (HR, 0.91; P = .09).

CONCLUSION

PORT is not associated with an improvement or detriment in OS for all patients with pN2 NSCLC. However, patients with a positive to sampled LN ratio ≥ 50% may benefit, regardless of chemotherapy status. Nevertheless, PORT will remain the standard of care as we await the results of the ongoing LUNG ART trial.

Exclusive cigar smoking in the United States and smoking-related diseases: A systematic review

BACKGROUND

Little information has been published on the risks of cigar smoking. Since 1990 cigar smoking has become more prevalent in the United States.

AIM

To summarise the evidence from the United States relating exclusive cigar smoking to risk of the major smoking-related diseases.

METHODS

Literature searches detected studies carried out in the United States which estimated the risk of lung cancer, chronic obstructive pulmonary disease (COPD), heart disease, stroke or overall circulatory disease in exclusive cigar smokers as compared to those who had never smoked any tobacco product. Papers were identified from reviews and detailed searches on MEDLINE. For each study, data were extracted onto a study database and a linked relative risk database. Relative risks and 95%CIs were extracted, or estimated, relating to current, former or ever exclusive cigar smokers, and meta-analysed using standard methods. Sensitivity analyses were conducted including or excluding results from studies that did not quite fit the full selection criteria (for example, a paper presenting combined results from five studies, where 86% of the population were in the United States).

RESULTS

The literature searches identified 17 relevant publications for lung cancer, four for COPD and 12 for heart disease, stroke and circulatory disease. These related to 11 studies for lung cancer, to four studies for COPD and to eight studies for heart disease, stroke or overall circulatory disease. As some studies provided results for more than one disease, the total number of studies considered was 13, with results from four of these used in sensitivity analyses. There was evidence of significant heterogeneity in some of the meta-analyses so the random-effects estimates are summarized below. As the results from the sensitivity analyses were generally very similar to those from the main analyses, and involved more data, only the sensitivity results are summarized below. For lung cancer, relative risks (95%CI) for current, former and ever smokers were respectively, 2.98 (2.08 to 4.26), 1.61 (1.23 to 2.09), and 2.22 (1.79 to 2.74) based on 6, 4 and 10 individual study estimates. For COPD, the corresponding estimates were 1.44 (1.16 to 1.77), 0.47 (0.02 to 9.88), and 0.86 (0.48 to 1.54) based on 4, 2 and 2 estimates. For ischaemic heart disease (IHD) the estimates were 1.11 (1.04 to 1.19), 1.26 (1.03 to 1.53) and 1.15 (1.08 to 1.23) based on 6, 3 and 4 estimates, while for stroke they were 1.02 (0.92 to 1.13), 1.08 (0.85 to 1.38), and 1.11 (0.95 to 1.31) based on 5, 3 and 4 estimates. For overall circulatory disease they were 1.10 (1.05 to 1.16), 1.11 (0.84 to 1.46), and 1.15 (1.06 to 1.26) based on 3, 3 and 4 estimates.

CONCLUSION

Exclusive cigar smoking is associated with an increased risk of lung cancer, and less so with COPD and IHD. The increases are lower than for cigarettes.

Stereotactic radiosurgery for acromegaly: an international systematic review and meta-analysis of clinical outcomes

INTRODUCTION

We performed a systematic review and meta-analysis of clinical outcomes for patients with acromegaly treated with stereotactic radiosurgery (SRS).

METHODS

Primary outcomes were 5- and 10-year endocrine remission (ER) and endocrine control (EC). Secondary outcomes were 10-year radiographic local control (LC), visual toxicity, and hypopituitarism rates. Weighted random effects meta-analyses using the DerSimonian and Laird methods were conducted to characterize and compare effect sizes. Mixed effects regression models were used to examine correlations between potential prognostic factors and primary and secondary outcomes.

RESULTS

In total, 1533 patients across 20 published studies with acromegaly treated with SRS were included. At 5-years, estimated ER and EC rates were 43.2% (95% CI 31.7-54.6%) and 55.0% (95% CI 27.6-82.4%), respectively. At 10-years, estimated ER and EC rates were 56.9% (95% CI 47.5-66.4%) and 69.7% (95% CI 47.7-91.8%), respectively. The estimated 10-year LC rate was 92.8% (95% CI 83.0-100%). Visual toxicity and hypopituitarism following SRS were estimated to be 2.7% (95% CI 1.3-4.2%) and 26.8% (95% CI 16.9-36.7%), respectively. Every 1 Gy increase in margin prescription dose beyond 17 Gy was estimated to result in a 0.41% increased risk of visual toxicity (p = 0.03). No prognostic factors were associated with EC, ER, LC, or hypopituitarism.

CONCLUSIONS

SRS was well-tolerated in the management of pituitary acromegaly resulting in gradually improving ER and EC rates over time that approached 60% and 70%. SRS-related visual loss is an uncommon treatment-related side effect, and patient-specific clinical decision making remains critical.

Systematic review with meta-analysis of the epidemiological evidence relating smoking to type 2 diabetes

BACKGROUND

Evidence relating tobacco smoking to type 2 diabetes has accumulated rapidly in the last few years, rendering earlier reviews considerably incomplete.

AIM

To review and meta-analyse evidence from prospective studies of the relationship between smoking and the onset of type 2 diabetes.

METHODS

Prospective studies were selected if the population was free of type 2 diabetes at baseline and evidence was available relating smoking to onset of the disease. Papers were identified from previous reviews, searches on Medline and Embase and reference lists. Data were extracted on a range of study characteristics and relative risks (RRs) were extracted comparing current, ever or former smokers with never smokers, and current smokers with non-current smokers, as well as by amount currently smoked and duration of quitting. Fixed- and random-effects estimates summarized RRs for each index of smoking overall and by various subdivisions of the data: Sex; continent; publication year; method of diagnosis; nature of the baseline population (inclusion/exclusion of pre-diabetes); number of adjustment factors; cohort size; number of type 2 diabetes cases; age; length of follow-up; definition of smoking; and whether or not various factors were adjusted for. Tests of heterogeneity and publication bias were also conducted.

RESULTS

The literature searches identified 157 relevant publications providing results from 145 studies. Fifty-three studies were conducted in Asia and 53 in Europe, with 32 in North America, and seven elsewhere. Twenty-four were in males, 10 in females and the rest in both sexes. Fifteen diagnosed type 2 diabetes from self-report by the individuals, 79 on medical records, and 51 on both. Studies varied widely in size of the cohort, number of cases, length of follow-up, and age. Overall, random-effects estimates of the RR were 1.33 [95% confidence interval (CI): 1.28-1.38] for current vs never smoking, 1.28 (95%CI: 1.24-1.32) for current vs non-smoking, 1.13 (95%CI: 1.11-1.16) for former vs never smoking, and 1.25 (95%CI: 1.21-1.28) for ever vs never smoking based on, respectively, 99, 156, 100 and 100 individual risk estimates. Risk estimates were generally elevated in each subdivision of the data by the various factors considered (exceptions being where numbers of estimates in the subsets were very low), though there was significant (P < 0.05) evidence of variation by level for some factors. Dose-response analysis showed a clear trend of increasing risk with increasing amount smoked by current smokers and of decreasing risk with increasing time quit. There was limited evidence of publication bias.

CONCLUSION

The analyses confirmed earlier reports of a modest dose-related association of current smoking and a weaker dose-related association of former smoking with type 2 diabetes risk.

Stereotactic radiosurgery for non-functioning pituitary adenomas: meta-analysis and International Stereotactic Radiosurgery Society practice opinion

BACKGROUND

This systematic review reports on outcomes and toxicities following stereotactic radiosurgery (SRS) for non-functioning pituitary adenomas (NFAs) and presents consensus opinions regarding appropriate patient management.

METHODS

Using the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses, a systematic review was performed from articles of ≥10 patients with NFAs published prior to May 2018 from the Medline database using the key words "radiosurgery" and "pituitary" and/or "adenoma." Weighted random effects models were used to calculate pooled outcome estimates.

RESULTS

Of the 678 abstracts reviewed, 35 full-text articles were included describing the outcomes of 2671 patients treated between 1971 and 2017 with either single fraction SRS or hypofractionated stereotactic radiotherapy (HSRT). All studies were retrospective (level IV evidence). SRS was used in 27 studies (median dose: 15 Gy, range: 5-35 Gy) and HSRT in 8 studies (median total dose: 21 Gy, range: 12-25 Gy, delivered in 3-5 fractions). The 5-year random effects local control estimate after SRS was 94% (95% CI: 93.0-96.0%) and 97.0% (95% CI: 93.0-98.0%) after HSRT. The 10-year local control random effects estimate after SRS was 83.0% (95% CI: 77.0-88.0%). Post-SRS hypopituitarism was the most common treatment-related toxicity observed, with a random effects estimate of 21.0% (95% CI: 15.0-27.0%), whereas visual dysfunction or other cranial nerve injuries were uncommon (range: 0-7%).

CONCLUSIONS

SRS is an effective and safe treatment for patients with NFAs. Encouraging short-term data support HSRT for select patients, and mature outcomes are needed before definitive recommendations can be made. Clinical practice opinions were developed on behalf of the International Stereotactic Radiosurgery Society (ISRS).

Single fraction radiosurgery, fractionated radiosurgery, and conventional radiotherapy for spinal oligometastasis (SAFFRON): A systematic review and meta-analysis

BACKGROUND AND PURPOSE

To perform a systematic review/meta-analysis of outcomes for patients with spinal metastases treated with stereotactic radiosurgery (SRS) (either single-fraction (SF-SRS) or multiple-fraction (MF-SRS)) or conventional radiotherapy (RT).

MATERIALS AND METHODS

Thirty-seven studies were identified. Primary outcomes were 1-year local control (LC) and acute/late grade 3-5 toxicities (including vertebral compression fractures (VCF)). Weighted random effects meta-analyses using the DerSimonian and Laird methods and meta-regressions were conducted to characterize and compare effect sizes. Mixed effects regression models were used in dose analyses.

RESULTS

A total of 3237 patients with 4911 lesions were included; 43.8%, 19.7%, and 36.5% of lesions received SF-SRS, MF-SRS, or RT, respectively. SF-SRS resulted in improved 1-year LC (92.9% (95% CI: 86.4-97.4%); p = 0.007) compared to RT (81.0% (95% CI: 69.2-90.5%)) with no difference between MF-SRS (82.1%; p = 0.86) and RT. On subgroup analysis of de novo metastases, superior 1-year LC following SF-SRS (95.5% (95% CI: 87.4-99.6%)) was maintained compared to RT (83.6% (95% CI: 70.4-93.5%); p = 0.007). A 4.7% increase in LC was noted for each 10 Gy₁₀ increase in biologically effective dose (BED₁₀, assuming an alpha/beta = 10) with SRS (p < 0.001). No difference in toxicities were found between SF-SRS (0.4%), MF-SRS (0.2%), or RT (0%). Higher VCF rates were noted following SF-SRS (19.5%) vs. MF-SRS (9.6%; p = 0.039)) with no correlation between dose and VCF rates.

CONCLUSION

SF-SRS resulted in superior LC with a roughly 5% LC benefit for every 10 Gy₁₀ increase in BED₁₀ with higher VCF rates compared to MF-SRS. If LC is the goal of treatment, then SRS may be a preferred treatment modality. However, these results are hypothesis-generating, and prospective randomized clinical trials are indicated to definitively address the question of whether SRS results in improved LC compared to RT.

Brain metastases from non-small cell lung cancer with EGFR or ALK mutations: A systematic review and meta-analysis of multidisciplinary approaches

BACKGROUND AND PURPOSE

To analyze outcomes of non-small cell lung cancer (NSCLC) patients with brain metastases harboring EGFR or ALK mutations and examine for differences between tyrosine kinase inhibitors (TKIs) alone, radiotherapy (RT) alone (either whole brain radiation therapy (WBRT) or stereotactic radiosurgery (SRS)), or combined TKIs and RT.

MATERIALS AND METHODS

Thirty studies were identified.

PATIENTS

with brain metastases from NSCLC.

INTERVENTION

initial TKIs alone with optional salvage RT, RT alone, or TKIs and RT.

CONTROL

wild-type NSCLC and TKIs alone for mutational and treatment analysis, respectively.

OUTCOMES

overall survival (OS) and intracranial progression-free survival (PFS).

SETTING

studies with mutation information.

RESULTS

A total of 2649 patients were included. Patients with ALK and EGFR mutations had significantly higher median OS (48.5 months, p < 0.0001; and 20.9 months; p = 0.0006, respectively) compared to wild-type patients (9.9 months). Similar median OS was noted between TKIs and RT (28.3 months), RT alone (32.2 months; p = 0.22), or TKIs alone (23.9 months; p = 0.2). Patients treated with TKIs and RT had higher median PFS (18.6 months; p = 0.06) compared to TKIs alone (13.6 months) with no difference between TKIs and RT vs. RT alone (16.9 months; p = 0.72). No PFS difference was found between WBRT and TKI (23.2 months; p = 0.72) vs. WBRT alone (24 months) or SRS and TKI (16.7 months; p = 0.56) vs. SRS alone (13.6 months).

CONCLUSION

NSCLC patients with brain metastases harboring EGFR or ALK mutations have superior OS compared to wild-type patients. No PFS or OS benefit was found with the addition of TKIs to RT.

Dose Escalation in Stereotactic Body Radiation Therapy for Pancreatic Cancer: A Meta-Analysis

OBJECTIVE

To determine whether increasing biologically effective dose (BED) with stereotactic body radiation therapy (SBRT) is associated with improved local control (LC) or toxicities in patients with locally advanced pancreatic cancer.

METHODS

A PICOS/PRISMA/MOOSE selection protocol was used to identify 15 studies across 12 institutions in 5 countries where patients received definitive SBRT for nonmetastatic disease. Biologically equivalent doses were calculated with an α/β of 10 (ie, BED10) for LC and acute toxicity and 3 (ie, BED3) for late toxicity. Fixed and random effects models were used to characterize LC and grade 3/4 toxicities by BED.

RESULTS

There were 508 patients included with a median follow-up time of 9.1 months. The median dose was 30 Gy, and the most common regimen was 30 Gy/5 fractions. There was no significant difference in LC rates at 1 year between the BED10<70 Gy versus ≥70 Gy groups, with an estimate of 0.60 (95% confidence interval [CI], 0.36-0.81) versus 0.83 (95% CI, 0.63-0.97), respectively. There was no significant difference in acute toxicity rates between the BED10<70 Gy versus ≥70 Gy groups, with an estimate of 0.02 (95% CI, 0.00-0.08) versus 0.05 (95% CI, 0.00-0.22), respectively. Given the dose distribution across studies, 3 intervals were used to characterize BED3. There were no significant differences in late toxicity among those receiving BED3<100, 100 to 200, or >200 Gy.

CONCLUSIONS

SBRT for pancreatic cancer results in LC rates of 60% to 83% and clinically significant toxicity of <7%. Increasing BED10 beyond 70 Gy was not associated with increased rates of 1-year LC or acute toxicity. Increasing BED3 beyond 100 Gy was not associated with increased rates of late toxicity.

Meta-Analyses in Plastic Surgery: Can We Trust Their Results?

BACKGROUND

Meta-analyses are common in the plastic surgery literature, but studies concerning their quality are lacking. The authors assessed the overall quality of meta-analyses in plastic surgery, and attempted to identify variables associated with scientific quality.

METHODS

A systematic review of meta-analyses published in seven plastic surgery journals between 2007 and 2017 was undertaken. Publication descriptors and methodologic details were extracted. Articles were assessed using the following two instruments: A Measurement Tool to Assess Systematic Reviews (AMSTAR) and AMSTAR 2.

RESULTS

Seventy-four studies were included. The number of meta-analyses per year increased. Most meta-analyses assessed a single intervention (59.5 percent), and pooled a mean of 20.9 studies (range, two to 134), including a mean of 2463 patients (range, 44 to 14,884). Most meta-analyses were published in Plastic and Reconstructive Surgery (44.6 percent) and included midlevel evidence (II to IV) primary studies. Only 16.2 percent of meta-analyses included randomized controlled trials. Meta-analyses generally reported positive (81.1 percent) and significant results (77.0 percent). Median AMSTAR score was 7 of 11 (interquartile range, 5 to 8). Higher AMSTAR scores correlated with more recent meta-analyses that provided a rationale for statistical pooling, and appropriately managed methodologic heterogeneity (r = 0.66; p < 0.01).

CONCLUSIONS

Despite an increase in number and quality, meta-analyses are at high risk of bias because of the low level of evidence of included primary studies and heterogeneity within and between primary studies. Plastic surgeons should be aware of the pitfalls of conducting and interpreting meta-analyses.

Comparison of bias adjustment methods in meta-analysis suggests that quality effects modeling may have less limitations than other approaches

BACKGROUND

The quality of primary research is commonly assessed before inclusion in meta-analyses. Findings are discussed in the context of the quality appraisal by categorizing studies according to risk of bias. The impact of appraised risk of bias on study outcomes is typically judged by the reader; however, several methods have been developed to quantify this risk of bias assessment and incorporate it into the pooled results of meta-analysis, a process known as bias adjustment. The advantages, potential limitations, and applicability of these methods are not well defined.

STUDY DESIGN AND SETTING

Comparative evaluation of the applicability of the various methods and their limitations are discussed using two examples from the literature. These methods include weighting, stratification, regression, use of empirically based prior distributions, and elicitation by experts.

RESULTS

Use of the two examples from the literature suggest that all methods provide similar adjustment. Methods differed mainly in applicability and limitations.

CONCLUSION

Bias adjustment is a feasible process in meta-analysis with several strategies currently available. Quality effects modelling was found to be easily implementable with fewer limitations in comparison to other methods.

Vascular Malformations and Health-Related Quality of Life: A Systematic Review and Meta-analysis

Importance

Patients with vascular malformations (VAMs) and vascular overgrowth syndromes have lower health-related quality of life (HRQoL) attributable to social stigmatization, poor mental health, severity, and pain. However, the factors that contribute to this decreased HRQoL are not clear.

Objective

To perform a systematic review and meta-analysis of studies that used validated HRQoL instruments to compare the HRQoL of persons with VAMs with the US general population.

Data Sources

A comprehensive search was performed in MEDLINE, Embase, PsycINFO, CINAHL, and Scopus from 1946 to March 31, 2017, with the consultation of an experienced librarian.

Study Selection

All VAM studies with validated HRQoL instruments published in the English language were included. Case reports, review articles, non-English-language publications, and studies about the development of new HRQoL instruments were not included.

Data Extraction and Synthesis

Two reviewers assessed studies' eligibility and the risk of bias and performed data extraction. The meta-analysis was performed using the random-effects model. Comparisons of means were performed using the unpaired, 2-sample t test.

Main Outcomes and Measures

The outcome was HRQoL.

Results

Eleven studies met the inclusion criteria for a total of 692 patients with VAMs. Six studies (320 patients) were included in the meta-analysis, whereas 5 studies were included in the qualitative analysis (372 patients). Those with VAMs had lower 36-Item Short-Form Health Survey scores in bodily pain (mean difference, -11.87; 95% CI, -21.45 to -2.29; I2 = 92%; P = .02) and mental health (mean difference, -6.04; 95% CI, -11.55 to -0.52; I2 = 83%; P = .03) compared with the US general population.

Conclusions and Relevance

Patients with VAMs had increased pain and psychosocial distress compared with the US general population. Pain and psychological morbidity are associated with poorer HRQoL and may serve as indicators for quality of life.

Transperitoneal versus retroperitoneal laparoscopic adrenalectomy for adrenal tumours in adults

BACKGROUND

Laparoscopic adrenalectomy is an accepted treatment worldwide for adrenal gland disease in adults. The transperitoneal approach is more common. The retroperitoneal approach may be preferred, to avoid entering the peritoneum, but no clear advantage has been demonstrated so far.

OBJECTIVES

To assess the effects of laparoscopic transperitoneal adrenalectomy (LTPA) versus laparoscopic retroperitoneal adrenalectomy (LRPA) for adrenal tumours in adults.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, ICTRP Search Portal, and ClinicalTrials.gov to 3 April 2018. We applied no language restrictions.

SELECTION CRITERIA

Two review authors independently scanned the abstract, title, or both sections of every record retrieved to identify randomised controlled trials (RCTs) on laparoscopic adrenalectomy for preoperatively assessed adrenal tumours. Participants were affected by corticoid and medullary, benign and malignant, functional and silent tumours or masses of the adrenal gland, which were assessed by both laboratory and imaging studies.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data, assessed trials for risk of bias, and evaluated overall study quality using GRADE criteria. We calculated the risk ratio (RR) for dichotomous outcomes, or the mean difference (MD) for continuous variables, and corresponding 95% confidence interval (CI). We primarily used a random-effects model for pooling data.

MAIN RESULTS

We examined 1069 publications, scrutinized 42 full-text publications or records, and included five RCTs. Altogether, 244 participants entered the five trials; 127 participants were randomised to retroperitoneal adrenalectomy and 117 participants to transperitoneal adrenalectomy. Two trials had a follow-up of nine months, and three trials a follow-up of 31 to 70 months. Most participants were women, and the average age was around 40 years. Three trials reported all-cause mortality; in two trials, there were no deaths, and in one trial with six years of follow-up, four participants died in the LRPA group and one participant in the LTPA group (164 participants; low-certainty evidence). The trials did not report all-cause morbidity. Therefore, we analysed early and late morbidity, and included specific adverse events under these outcome measures. The results were inconclusive between LRPA and LTPA for early morbidity (usually reported within 30 to 60 days after surgery; RR 0.56, 95% CI 0.27 to 1.16; P = 0.12; 5 trials, 244 participants; very low-certainty evidence). Nine out of 127 participants (7.1%) in the LRPA group, compared with 16 out of 117 participants (13.7%) in the LTPA group experienced an adverse event. Participants in the LRPA group may have a lower risk of developing late morbidity (reported as latest available follow-up; RR 0.12, 95% CI 0.01 to 0.92; P = 0.04; 3 trials, 146 participants; very low-quality evidence). None of the 78 participants in the LRPA group, compared with 7 of the 68 participants (10.3%) in the LTPA group experienced an adverse event.None of the trials reported health-related quality of life. The results were inconclusive for socioeconomic effects, assessed as time to return to normal activities and length of hospital stay, between the intervention and comparator groups (very low-certainty evidence). Participants who had LRPA may have had an earlier start on oral fluid or food intake (MD -8.6 hr, 95% CI -13.5 to -3.7; P = 0.0006; 2 trials, 89 participants), and ambulation (MD -5.4 hr, 95% CI -6.8 to -4.0 hr; P < 0.0001; 2 trials, 89 participants) than those in the LTPA groups. Postoperative and operative parameters (duration of surgery, operative blood loss, conversion to open surgery) showed inconclusive results between the intervention and comparator groups.

AUTHORS' CONCLUSIONS

The body of evidence on laparoscopic retroperitoneal adrenalectomy compared with laparoscopic transperitoneal adrenalectomy is limited. Late morbidity might be reduced following laparoscopic retroperitoneal adrenalectomy, but we are uncertain about this effect because of very low-quality evidence. The effects on other key outcomes, such as all-cause mortality, early morbidity, socioeconomic effects, and operative and postoperative parameters are uncertain. LRPA might show a shorter time to oral fluid or food intake and time to ambulation, but we are uncertain whether this finding can be replicated. New long-term RCTs investigating additional data, such as health-related quality of life, surgeons' level of experience, treatment volume of surgical centres, and details on techniques used are needed.

Single versus Multifraction Stereotactic Radiosurgery for Large Brain Metastases: An International Meta-analysis of 24 Trials

PURPOSE

Multifraction (MF) stereotactic radiosurgery (SRS) purportedly reduces radionecrosis risk over single-fraction (SF) SRS in the treatment of large brain metastases. The purpose of the current work is to compare local control (LC) and radionecrosis rates of SF-SRS and MF-SRS in the definitive (SF-SRS_D and MF-SRS_D) and postoperative (SF-SRS_P and MF-SRS_P) settings.

METHODS AND MATERIALS

Population, Intervention, Control, Outcomes, Study Design/Preferred Reporting Items for Systematic Reviews and Meta-analyses and Meta-analysis of Observational Studies in Epidemiology guidelines were used to select articles in which patients had "large" brain metastases (Group A: 4-14 cm³, or about 2-3 cm in diameter; Group B: >14 cm³, or about >3 cm in diameter); 1-year LC and/or rates of radionecrosis were reported; radiosurgery was administered definitively or postoperatively. Random effects meta-analyses using fractionation scheme and size as covariates were conducted. Meta-regression and Wald-type tests were used to determine the effect of increasing tumor size and fractionation on the summary estimate, where the null hypothesis was rejected for P < .05.

RESULTS

Twenty-four studies were included, published between 2008 and 2017, with 1887 brain metastases. LC random effects estimate at 1 year was 77.6% for Group A/SF-SRS_D and 92.9% for Group A/MF-SRS_D (P = .18). LC random effects estimate at 1 year was 77.1% for Group B/SF-SRS_D and 79.2% for Group B/MF-SRS_D (P = .76). LC random effects estimate at 1 year was 62.4% for Group B/SF-SRS_P and 85.7% for Group B/MF-SRS_P (P = .13). Radionecrosis incidence random effects estimate was 23.1% for Group A/SF-SRS_D and 7.3% for Group A/MF-SRS_D (P = .003). Radionecrosis incidence random effects estimate was 11.7% for Group B/SF-SRS_D and 6.5% for Group B/MF-SRS_D (P = .29). Radionecrosis incidence random effects estimate was 7.3% for Group B/SF-SRS_P and 7.5% for Group B/MF-SRS_P (P = .85). Metaregression assessing 1-year LC and radionecrosis as a continuous function of increasing tumor volume was not statistically significant.

CONCLUSIONS

Treatment for large brain metastases with MF-SRS regimens may offer a relative reduction of radionecrosis while maintaining or improving relative rates of 1-year LC compared with SF-SRS. These findings are hypothesis-generating and require validation by ongoing and planned prospective clinical trials.

Improving the conduct of meta-analyses of observational studies

The author, who has published numerous meta-analyses of epidemiological studies, particularly on tobacco, comments on various aspects of their content. While such meta-analyses, even when well conducted, are more difficult to draw inferences from than are meta-analyses of clinical trials, they allow greater insight into an association than do simple qualitative reviews. This editorial starts with a discussion of some problems relating to hypothesis definition. These include the definition of the outcome, the exposure and the population to be considered, as well as the study inclusion and exclusion criteria. Under literature searching, the author argues against restriction to studies published in peer-reviewed journals, emphasising the fact that relevant data may be available from other sources. Problems of identifying studies and double counting are discussed, as are various issues in regard to data entry. The need to check published effect estimates is emphasised, and techniques to calculate estimates from material provided in the source publication are described. Once the data have been collected and an overall effect estimate obtained, tests for heterogeneity should be conducted in relation to different study characteristics. Though some meta-analysts recommend classifying studies by an overall index of study quality, the author prefers to separately investigate heterogeneity by those factors which contribute to the assessment of quality. Reasons why an association may not actually reflect a true causal relationship are also discussed, with the editorial describing techniques for investigating the relevance of confounding, and referring to problems resulting from misclassification of key variables. Misclassification of disease, exposure and confounding variables can all produce a spurious association, as can misclassification of the variable used to determine whether an individual can enter the study, and the author points to techniques to adjust for this. Issues relating to publication bias and the interpretation of “statistically significant” results are also discussed. The editorial should give the reader insight into the difficulties of producing a good meta-analysis.

Cardiovascular disease risk factors in chronic kidney disease: A systematic review and meta-analysis

BACKGROUND AND OBJECTIVES

Chronic kidney disease (CKD) is a global health burden and is independently associated with increased cardiovascular disease risk. Assessment of cardiovascular risk in the general population using prognostic models based on routinely collected risk factors is embedded in clinical practice. In CKD, prognostic models may misrepresent risk due to the interplay of traditional atherosclerotic and non-traditional risk factors. This systematic review's aim was to identify routinely collected risk factors for inclusion in a CKD-specific cardiovascular prognostic model.

DESIGN, SETTING, PARTICIPANTS AND MEASUREMENTS

Systematic review and meta-analysis of observational cohort studies and randomized controlled trials. Studies identified from MEDLINE and Embase searches using a pre-defined and registered protocol (PROSPERO ID-2016:CRD42016036187). The main inclusion criteria were individuals ≥18 years of age with non-endstage CKD. Routinely collected risk factors where multi-variable adjustment for established cardiovascular risk factors had occurred were extracted. The primary outcome was fatal and non-fatal cardiovascular events.

RESULTS

The review of 3,232, abstracts identified 29 routinely collected risk factors of which 20 were presented in more than 1 cohort. 21 cohorts were identified in relation to 27,465 individuals and 100,838 person-years. In addition to established traditional general population cardiovascular risk factors, left ventricular hypertrophy, serum albumin, phosphate, urate and hemoglobin were all found to be statistically significant in their association with future cardiovascular events.

CONCLUSIONS

These non-traditional risk factors should be assessed in the development of future cardiovascular prognostic models for use in individuals with CKD.

Tar level of cigarettes smoked and risk of smoking-related diseases

BACKGROUND

Opinions differ on the relationship between tar level and risk of smoking-related disease. However, except for lung cancer, few reviews have evaluated the epidemiological evidence. Here the relationship of tar level to risk of the four main smoking-related diseases is considered.

METHODS

Papers comparing risk of lung cancer, COPD, heart disease or stroke in smokers of lower and higher tar yield cigarettes were identified from reviews and searches, relative risk estimates being extracted comparing the lowest and highest tar groups. Meta-analyses investigated heterogeneity by various study characteristics.

RESULTS

Twenty-six studies were identified, nine of prospective design and 17 case-control. Two studies grouped cigarettes by nicotine rather than tar. Seventeen studies gave results for lung cancer, 16 for heart disease, five for stroke and four for COPD. Preferring relative risks adjusted for daily amount smoked, where adjusted and unadjusted estimates were available, combined estimates for lowest versus highest tar (or nicotine) groups were 0.78 (95% confidence interval 0.70-0.88) for lung cancer, 0.86 (0.81-0.91) for heart disease, 0.77 (0.62-0.95) for stroke and 0.81 (0.65-1.02) for COPD. Lower risks were generally evident in subgroups by publication period, gender, study design, location and extent of confounder adjustment. Estimates were similar preferring data unadjusted for amount smoked or excluding nicotine-based estimates.

CONCLUSIONS

Despite evidence that smokers substantially compensate for reduced cigarette yields, the results clearly show lower risks in lower tar smokers. Limitations of the evidence are discussed, but seem unlikely to affect this conclusion.

The relationship of cigarette smoking in Japan to lung cancer, COPD, ischemic heart disease and stroke: A systematic review

Background:  To present up-to-date meta-analyses of evidence from Japan relating smoking to major smoking-related diseases.  Methods:  We restricted attention to lung cancer, chronic obstructive pulmonary disease (COPD), ischemic heart disease (IHD) and stroke, considering relative risks (RRs) for current and ex-smokers relative to never smokers.  Evidence by amount smoked and time quit was also considered.  For IHD and stroke only, studies had to provide age-adjusted RRs, with age-specific results considered.  For each disease we extended earlier published databases to include more recent studies.  Meta-analyses were conducted, with random-effects RRs and tests of heterogeneity presented.  Results:  Of 40 studies, 26 reported results for lung cancer and 7 to 9 for each other disease.  For current smoking, RRs (95%CIs) were lung cancer 3.59 (3.25-3.96), COPD 3.57 (2.72-4.70), IHD 2.21 (1.96-2.50) and stroke 1.40 (1.25-1.57).  Ex-smoking RRs were lower.  Data for lung cancer and IHD showed a clear tendency for RRs to rise with increasing amount smoked and decrease with increasing time quit.  Dose-response data were unavailable for COPD and unclear for stroke, where the association was weaker.  Conclusions:  Compared to studies in other Asian and Western countries, current smoking RRs were quite similar for IHD and stroke.  The comparison is not clear for COPD, where the Japanese data, mainly from cross-sectional studies, is limited.  For lung cancer, the RRs are similar to those in other Asian countries, but substantially lower than in Western countries.  Explanations for this are unclear, but less accurate reporting of smoking by Japanese may contribute to the difference.