A critical appraisal of epidemiological studies comes from basic knowledge: a reader's guide to assess potential for biases

Scientific literature may be biased because of the internal validity of studies being compromised by different forms of measurement error, and/or because of the selective reporting of positive and 'statistically significant' results. While the first source of bias might be prevented, and in some cases corrected to a degree, the second represents a pervasive problem afflicting the medical literature; a situation that can only be 'corrected' by a change in the mindset of authors, reviewers, and editors. This review focuses on the concepts of confounding, selection bias and information bias, utilising explanatory examples and simple rules to recognise and, when possible, to correct for them. Confounding is a mixing of effects resulting from an imbalance of some of the causes of disease across the compared groups. It can be prevented by randomization and restriction, and controlled by stratification, standardization or by using multivariable techniques. Selection bias stems from an absence of comparability among the groups being studied, while information bias arises from distorted information collection techniques. Publication bias of medical research results can invalidate evidence-based medicine, when a researcher attempting to collect all the published studies on a specific topic actually gathers only a proportion of them, usually the ones reporting 'positive' results. The selective publication of 'statistically significant' results represents a problem that researchers and readers have to be aware of in order to face the entire body of published medical evidence with a degree of scepticism

Robotic rectal resection preserves anorectal function: Systematic review and meta-analysis.

AbstractBackgroundImproving survival rates in rectal cancer patients has generated a growing interest in functional outcomes after total mesorectal excision (TME). The well‐established low anterior resection syndrome (LARS) score assesses postoperative anorectal impairment after TME. Our meta‐analysis is the first to compare bowel function after open, laparoscopic, transanal, and robotic TME.MethodsAll studies reporting functional outcomes after rectal cancer surgery (LARS score) were included, and were compared with a consecutive series of robotic TME (n = 48).ResultsThirty‐two publications were identified, including 5 565 patients. Anorectal function recovered significantly better within one year after robotic TME (3.8 [95%CI –9.709–17.309]) versus laparoscopic TME (26.4 [95%CI 19.524–33.286]), p = 0.006), open TME (26.0 [95%CI 24.338–29.702], p = 0.002) and transanal TME (27.9 [95%CI 22.127–33.669], p = 0.003).ConclusionsRobotic TME enables better recovery of anorectal function compared to other techniques. Further prospective, high‐quality studies are needed to confirm the benefits of robotic surgery

Adult height and risk of gastric cancer: a pooled analysis within the Stomach cancer Pooling Project

Background: The association between height and risk of gastric cancer has been studied in several epidemiological studies with contrasting results. The aim of this study is to examine the association between adult height and gastric cancer within a large pooled analysis of case-control studies members of the Stomach cancer Pooling (StoP) Project consortium. Methods: Data from 18 studies members of the StoP consortium were collected and analyzed. A multivariable logistic regression model was used to estimate the study-specific odds ratios (ORs) and 95% confidence intervals (CIs) for the association between 10-cm increase in height and risk of gastric cancer. Age, sex, tobacco smoking, alcohol consumption, social class, geographical area and Helicobacter pylori (H. pylori) status were included in the regression model. Resulting estimates were then pooled with random-effect model. Analyses were conducted overall and in strata of selected variables. Results: A total of 7562 cases and 19 033 controls were included in the analysis. The pooled OR was 0.96 (95% CI 0.87-1.05). A sensitivity analysis was performed restricting the results to the studies with information on H. pylori status, resulting in an OR of 0.97 (95% CI 0.79-1.20). Conclusion: Our study does not support a strong and consistent association between adult height and gastric cancer

The Prognostic Impact of the Metastatic Lymph Nodes Ratio in Colorectal Cancer

Background: This study was designed to validate the prognostic significance of the ratio of positive to examined lymph nodes (LNR) in patients with colorectal cancer.Methods: 218,314 patients from the SEER database and 1,811 patients from the three independent multicenter were included in this study. The patients were divided into 5 groups on a basis of previous published LNR: LNR0, patients with no metastatic lymph nodes; LNR1, patients with the LNR between 0.1 and 0.17; LNR2, patients with the LNR between 0.18 and 0.41; LNR3, patients with the LNR between 0.42 and 0.69; LNR4, patients with the LNR >0.7. The 5-year OS and CSS rate were estimated using Kaplan-Meier method and the survival difference was tested using log-rank test. Multivariate Cox analysis was used to further assess the influence of the LNR on patients' outcome.Results: The 5-year OS rate of patients within LNR0 to LNR4 group was 71.2, 55.8, 39.3, 22.6, and 14.6%, respectively (p < 0.001) in the SEER database. While the 5-year OS rate of those with LNR0 to LNR4 was 75.2, 66.1, 48.0, 34.0, and 17.7%, respectively (p < 0.001) in the international multicenter cohort. In the multivariate analysis, LNR was demonstrated to be a strong prognostic factor in patients with < 12 and ≥12 metastatic lymph nodes. Furthermore, the LNR had a similar impact on the patients' prognosis in colon cancer and rectal cancer.Conclusion: The LNR allowed better prognostic stratification than the positive node (pN) in patients with colorectal cancer and the cut-off values were well validated

Telocytes are the physiological counterpart of inflammatory fibroid polyps and PDGFRA-mutant GISTs

PDGFRA mutations in the gastrointestinal (GI) tract can cause GI stromal tumour (GIST) and inflammatory fibroid polyp (IFP). Hitherto no cell type has been identified as a physiological counterpart of the latter, while interstitial Cajal cells (ICC) are considered the precursor of the former. However, ICC hyperplasia (ICCH), which strongly supports the ICC role in GIST pathogenesis, has been identified in germline KIT-mutant settings but not in PDGFRA-mutant ones, challenging the precursor role of ICC for PDGFRA-driven GISTs. Telocytes are a recently described interstitial cell type, CD34+/PDGFRA+. Formerly considered fibroblasts, they are found in many organs, including the GI tract where they are thought to be involved in neurotransmission. Alongside IFPs and gastric GISTs, GI wall \u201cfibrosis\u201d has been reported in germline PDGFRA-mutants. Taking the opportunity offered by its presence in a germline PDGFRA-mutant individual, we demonstrate that this lesion is sustained by hyperplastic telocytes, constituting the PDGFRA-mutant counterpart of germline KIT mutation-associated ICCH. Moreover, our findings support a pathogenetic relationship between telocyte hyperplasia and both IFPs and PDGFRA-mutant GISTs. We propose the term \u201ctelocytoma\u201d for defining IFP, as it conveys both the pathogenetic (neoplastic) and histotypic (\u201ctelocytary\u201d) essence of this tumour, unlike IFP, which rather evokes an inflammatory-hyperplastic lesion

The Road to Curative Surgery in Gastric Cancer Treatment: A Different Path in the Elderly?

BACKGROUND: The aim of this study was to evaluate the possibility of a different path to achieve curative surgery in patients older than age 70 years and affected by resectable gastric cancer. STUDY DESIGN: This is a multicentric retrospective study based on an analysis of 1,465 patients with gastric adenocarcinoma who underwent surgery with curative intent. Patients were divided into 2 age groups (younger than 70 years vs older than 70 years) and were evaluated with respect to postoperative morbidity and mortality and survival. RESULTS: Postoperative morbidity and mortality in elderly and nonelderly groups were 24.8% vs 20.6% and 2.6% vs 3.7%, respectively (p = NS). In the elderly group, multivisceral resection was independently associated with surgical complications (hazard ratio [HR] = 1.988; 95% CI, 1.124-3.516; p = 0.018), total gastrectomy with medical complications (HR = 2.007; 95% CI, 1.165-3.459; p = 0.012), and higher postoperative mortality (HR = 4.319; 95% CI, 1.571-11.873; p = 0.005); D1 lymph node dissection was predictive of a lower postoperative mortality rate (HR = 0.219; 95% CI, 0.080-0.603; p = 0.003). Five-year overall survival rates differed significantly in young and elderly patients (58.9% vs 38.9%; p < 0.001), and 5-year cancer-specific survival did not show any significant difference. CONCLUSIONS: Age should not be considered as a factor in the selection of treatment for gastric cancer patients. Curative surgery can be performed as safely in elderly patients as in younger patients, with comparable postoperative results and long-term survival rates, although the life expectancy of elderly patients is shorter

Safety and efficacy of totally minimally invasive right colectomy in the obese patients: a multicenter propensity score-matched analysis

Despite the well-known benefits of the minimally invasive approach for the right colon cancer treatment, less is known about its feasibility and advantages in morbid obese patients. The aim of this study is to compare the postoperative outcomes after totally minimally invasive right colectomy between the obese and non-obese population. Data derived from a prospectively maintained multicenter colorectal database were analysed, dividing the enrolled patients into two groups: obese (BMI > 29.99) patient group and non-obese patient group. Data about gender, age, American Society of Anesthesiologists (ASA) Score, tumor characteristics, operative time, anastomosis time, extraction site, incision length, intraoperative complications, postoperative complications, postoperative recovery, specimen length and retrieved nodes were taken to assess the achievement of the oncologic standards. After a propensity score matching, a total of 184 patients was included, 92 in each group. No differences were found in terms of demographic data and tumor characteristics. Intraoperative data showed a significant difference in terms of anastomosis time in favour of non-obese group (p < 0.0001). No intraoperative complications were recorded and no conversion was needed in both groups. No differences were found in terms of postoperative complications. There were no differences in terms of first mobilization (p = 0.745), time to first flatus (p = 0.241) time to tolerance to liquid and solid diet (p = 0.241 and p = 0.06) and length of hospital stay (p = 0.817). The analysis of oncologic outcomes demonstrated adequate results in both groups. The results obtained by our study confirmed the feasibility and safety of the totally minimally invasive approach even in obese population

Colorectal surgery in Italy during the Covid19 outbreak: a survey from the iCral study group

Background The COVID19 pandemic had a deep impact on healthcare facilities in Italy, with profound reorganization of surgical activities. The Italian ColoRectal Anastomotic Leakage (iCral) study group collecting 43 Italian surgical centers experienced in colorectal surgery from multiple regions performed a quick survey to make a snapshot of the current situation. Methods A 25-items questionnaire was sent to the 43 principal investigators of the iCral study group, with questions regard- ing qualitative and quantitative aspects of the surgical activity before and after the COVID19 outbreak. Results Two-thirds of the centers were involved in the treatment of COVID19 cases. Intensive care units (ICU) beds were partially or totally reallocated for the treatment of COVID19 cases in 72% of the hospitals. Elective colorectal surgery for malignancy was stopped or delayed in nearly 30% of the centers, with less than 20% of them still scheduling elective colo- rectal resections for frail and comorbid patients needing postoperative ICU care. A significant reduction of the number of colorectal resections during the time span from January to March 2020 was recorded, with significant delay in treatment in more than 50% of the centers. Discussion Our survey confirms that COVID19 outbreak is severely affecting the activity of colorectal surgery centers partici- pating to iCral study group. This could impact the activity of surgical centers for many months after the end of the emergency

ICG fluorescence imaging in colorectal surgery: a snapshot from the ICRAL study group

Background: Fluorescence-guided visualization is a recently proposed technology in colorectal surgery. Possible uses include evaluating perfusion, navigating lymph nodes and searching for hepatic metastases and peritoneal spread. Despite the absence of high-level evidence, this technique has gained considerable popularity among colorectal surgeons due to its significant reliability, safety, ease of use and relatively low cost. However, the actual use of this technique in daily clinical practice has not been reported to date. Methods: This survey was conducted on April 2020 among 44 centers dealing with colorectal diseases and participating in the Italian ColoRectal Anastomotic Leakage (iCral) study group. Surgeons were approximately equally divided based on geographical criteria from multiple Italian regions, with a large proportion based in public (89.1%) and nonacademic (75.7%) centers. They were invited to answer an online survey to snapshot their current behaviors regarding the use of fluorescence-guided visualization in colorectal surgery. Questions regarding technological availability, indications and techniques, personal approaches and feelings were collected in a 23-item questionnaire. Results: Questionnaire replies were received from 37 institutions and partially answered by 8, as this latter group of centers do not implement fluorescence technology (21.6%). Out of the remaining 29 centers (78,4%), fluorescence is utilized in all laparoscopic colorectal resections by 72.4% of surgeons and only for selected cases by the remaining 27.6%, while 62.1% of respondents do not use fluorescence in open surgery (unless the perfusion is macroscopically uncertain with the naked eye, in which case 41.4% of them do). The survey also suggests that there is no agreement on dilution, dosing and timing, as many different practices are adopted based on personal judgment. Only approximately half of the surgeons reported a reduced leak rate with fluorescence perfusion assessment, but 65.5% of them strongly believe that this technique will become a minimum requirement for colorectal surgery in the future. Conclusion: The survey confirms that fluorescence is becoming a widely used technique in colorectal surgery. However, both the indications and methods still vary considerably; furthermore, the surgeons' perceptions of the results are insufficient to consider this technology essential. This survey emphasizes the need for further research to reach recommendations based on solid scientific evidence. Keywords: Colon cancer; Fluorescence guided surgery; ICG; Laparoscopy; Rectal cancer