Nomogram-Based Prognostic Evaluation of Gastric Cancer Patients with Low Counts of Examined Lymph Nodes Outperforms the Predictive Ability of the 7th and 8th Editions of the American Joint Committee on Cancer Staging System.

BACKGROUND: The American Joint Committee on Cancer (AJCC) staging system has limited accuracy in predicting survival of gastric cancer patients with inadequate counts of evaluated lymph nodes (LNs). We therefore aimed to develop a prognostic nomogram suitable for clinical applications in such cases. METHODS: A total of 1511 noncardia gastric cancer patients treated between 1990 and 2010 in the academic surgical center were reviewed to compare the 7th and 8th editions of the AJCC staging system. A nomogram was developed for the prediction of 5-year survival in patients with less than 16 LNs evaluated (n = 546). External validation was performed using datasets derived from the Polish Gastric Cancer Study Group (n = 668) and the SEER database (n = 11,225). RESULTS: The 8th edition of AJCC staging showed better overall discriminatory power compared to the previous version, but no improvement was found for patients with < 16 evaluated LNs. The developed nomogram had better concordance index (0.695) than the former (0.682) or latest (0.680) staging editions, including patients subject to neoadjuvant treatment, and calibration curves showed excellent agreement between the nomogram-predicted and actual survival. High discriminatory power was also demonstrated for both validation cohorts. Subsequently, the nomogram showed the best accuracy for the prediction of 5-year survival through the time-dependent ROC curve analysis in the training and validation cohorts. CONCLUSIONS: A clinically relevant nomogram was built for the prediction of 5-year survival in patients with inadequate numbers of LNs evaluated in surgical specimens. The predictive accuracy of the nomogram was validated in two Western populations.

Clinicopathological Prognostic Factors Determining Outcomes of Treatment in Gastric Cancer Surgery.

BACKGROUND/AIM: The purpose of this study was to examine the impact of clinicopathological prognostic factors on tumor resectability, perioperative complications, and 5-year survival rates in patients with gastric cancer treated surgically. PATIENTS AND METHODS: A cohort of 834 patients operated on for gastric cancer between 2007 and 2016 was analyzed. RESULTS: Patients over 70 years of age manifested a significantly higher rate of overall complications, systemic complications, surgical complications, perioperative mortality, and a worse 5-year survival. The diffuse type according to the Lauren classification was an independent prognostic factor for perioperative mortality. TNM stage significantly influenced resectability and 5-year survival rates. Furthermore, the presence of distant metastases (M1 stage) significantly increased the rates of overall complications, systemic complications, and perioperative mortality. CONCLUSION: Although TNM stage was the most important prognostic factor for resectability, perioperative complications and 5-year survival, other clinicopathological prognostic factors, such as age, and Lauren type also significantly affected treatment outcomes in gastric cancer surgery.

Analysis of Prognostic Factors Affecting Short-term and Long-term Outcomes of Gastric Cancer Resection.

BACKGROUND: The aim of this study was the analysis of the influence of prognostic factors on short- and long-term outcomes of gastric cancer resection. PATIENTS AND METHODS: A database of 709 patients who had gastric cancer resection between 2007 and 2015 was compiled. RESULTS: Total gastrectomy (TG) and subtotal proximal gastrectomy (SPG) significantly increased the risk of overall complications (p=0.0015 and 0.0173, respectively) and surgical complications (p=0.0141 and 0.0035, respectively). Moreover the resection of an additional organ was an independent prognostic factor of overall complications (p<0.0001), systemic complications (p=0.0503), surgical complications (p<0.0001) and relaparotomy (p=0.0259). T stage (p<0.0001), N stage (p<0.0001), M stage (p<0.0001) and radical resection (p<0.0001) significantly affected 5-year survival rates. CONCLUSION: Early diagnosis and radical resection was crucial in 5-year survival rates. However, the type of gastrectomy and the resection of an additional organ were the most important factors in short-term outcomes of treatment for such patients.

Types and implications of abdominal fluid collections following gastric cancer surgery.

Background: Little data are available for abscess and non-abscess abdominal fluid collections (AFCs) after gastric cancer surgery and their clinical implications. We sought to analyse the natural history of such collections in a population of patients subject to routine postoperative imaging.Methods: From 1996 to 2012, 1381 patients underwent gastric resections and routine postoperative monitoring with abdominal ultrasound. As a unit protocol, examinations were carried out in all patients prior to drain removal, immediately before discharge, and at follow-up visits.Results: AFCs were diagnosed in 134 (9.7%) patients after a median time from surgery of seven days (interquartile range (IQR) 5-11 days). Sixty-four of the 134 AFCs (48%) were asymptomatic and resolved spontaneously after a median follow-up of 26.5 days (IQR 14-91 days). Seventy (52%) AFCs required interventional drainage. A stepwise logistic regression model demonstrated that interventional treatment was much more likely among patients with enteric fistula (odds ratio (OR) 9.542, 95% CI 1.418-46.224, p=.003) and pancreatic fistula (OR 7.157, 95% CI 1.340-39.992, p=.012).Conclusions: About one half of AFCs after gastric surgery were asymptomatic and eventually resolved spontaneously without any intervention. However, the need for interventional drainage was significantly increased by coexisting pancreatic or enteric fistula.

Analysis of clinicopathologic characteristics of gastric cancer in patients ≤40 and ≥40 years of age.

Objectives: Gastric cancer (GC) in young patients is a troubling clinical problem. The aim of this study was to analyze whether patients ≤40 years of age with GC differ from patients (age >40 years) in terms of clinicopathological and selected genetic factors.Materials and methods: Between 1984 and 2011, data were collected for 840 GC patients diagnosed and treated for GC at the Department of Gastroenterology at Pomeranian Medical University. The following clinicopathological features were compared between two age groups: sex, symptom duration, family history of cancer, tumor site, stage (early vs. advanced), blood group, histology, Helicobacter pylori infection and BRCA2 C572T silent mutation status.Results: A total of 65 (7.7%) patients were age 40 years or younger. GC was predominant in women in the younger group (p < .001). Patients (≤40 years) more frequently reported a positive family history of cancer (p = .01) and a diffuse tumor type was more common in this group (p < .001). The two age groups did not differ significantly regarding symptom duration, tumor location or stage, H. pylori infection, blood group, or BRCA2 C572T silent mutation status. A comparison of male and female patients aged 40 years or less did not reveal sex-based differences in any analyzed features.Conclusion: Patients ≤40 years of age with GC differ from patient >40 years of age in having a predominance of women, diffuse tumor type, and positive family history of cancer. These results offer openings for further investigation of the relevance of these differences.

Rationale and feasibility of mucin expression profiling by qRT-PCR as diagnostic biomarkers in cytology specimens of pancreatic cancer.

BACKGROUND: Aberrantly expressed mucin glycoproteins (MUC) play important roles in pancreatic ductal adenocarcinoma (PDAC), yet their use as a diagnostic aid in fine-needle aspiration biopsy (FNAB) is poorly documented. The aim of this study was to investigate the rationale and feasibility of mucin (MUC1, MUC2, MUC3, MUC4, MUC5AC, and MUC6) expression profiling by RT-PCR for diagnostic applications in cytology. METHODS: Mucin expression was examined by RT-PCR and immunohistochemistry in specimens resected from patients with pancreatic (n = 101), ampullary (n = 23), and common bile duct (n = 10) cancers and 33 with chronic pancreatitis. Furthermore, mucin profiling by RT-PCR was prospectively compared in surgical and biopsy specimens of 40 patients with pancreatic solid tumours qualified for FNAB prior to surgery. RESULTS: A logistic regression model to distinguish PDAC from chronic pancreatitis using RT-PCR profiling included MUC3, MUC5AC, and MUC6. The same set of mucins differentiated ampullary and bile duct cancers from chronic pancreatitis. AUCs for the ROC curves derived from the two models were 0.95 (95%CI 0.87-0.99) and 0.92 (95%CI 0.81-0.98), respectively. The corresponding positive likelihood ratios were 6.02 and 5.97, while the negative likelihood ratios were 0.10 and 0.12. AUCs of ROC curves obtained by RT-PCR and immunohistochemistry demonstrated that both analytical methods were comparable. Surgical and cytological samples showed significantly correlated values of ΔCt for individual mucins with the overall Pearson's correlation coefficient r = 0.841 (P = 0.001). CONCLUSIONS: Mucin expression profiling of pancreatic cancer with RT-PCR is feasible and may be a valuable help in discriminating malignant lesions from chronic pancreatitis in FNAB cytology.

The Impact of Postoperative Enteral Immunonutrition on Postoperative Complications and Survival in Gastric Cancer Patients - Randomized Clinical Trial.

BACKGROUND: Immunomodulating enteral nutrition in the perioperative period may reduce postoperative complications in cancer patients. Little is known if this effect translates to the better survival. The aim of study was to assess the impact of postoperative immunomodulating enteral nutrition on postoperative complications and survival of gastric cancer patients. METHODS: A group of 98 gastric cancer patients was randomly assigned for postoperative immunomodulating enteral nutrition n = 44 (Reconvan, Fresenius Kabi, Bad Homburg, Germany), or standard enteral nutrition n = 54 (Peptisorb, Nutricia, Schipol, The Netherlands). Postoperative complications, mortality, 6-mo and 1-yr survival were analyzed. RESULTS: The overall postoperative morbidity did not differ between the groups. The rate of pulmonary complications (excluding pneumonia) was significantly lower in immunomodulation group (0% vs 9.3%, p = 0.044), as well as 60-day mortality (0% vs. 11.1%, p = 0.037). There was no difference in 6-mo and 1-yr survival between the groups. CONCLUSIONS: Postoperative immunomodulating enteral nutrition may reduce respiratory complications and postoperative mortality in comparison to standard enteral nutrition. Despite this effect, it did not improve 6-mo and 1-yr survival in immunomodulation group. Probably the beneficial effect of immunomodulating enteral nutrition is too weak to be significant in such a number of patients.

Polish Consensus on Treatment of Gastric Cancer; update 2017.

The "Polish Research on Gastric Cancer" project has been continued since 1986. The main aim of this project, which is a multicenter and interdisciplinary research, is enhancing the treatment results of gastric cancer patients by developing and promoting the use of optimal methods for diagnosis and treatment, both surgical as well as combined. One of the more important achievements of the project is the development and publication of a document named "Polish Consensus on Treatment of Patients with Gastric Cancer", whose first version was published in 1998. Following versions were updated adequately to changing trends in the proceedings in patients with gastric cancer. A scientific symposium on "Polish Consensus on Treatment of Gastric Cancer - update 2016" was held in 3-4 June 2016 in Cracow. During the symposium a panel session was held during which all authors publicly presented the Consensus assumptions to be discussed further. Moreover, the already mentioned session was preceded by a correspondence as well as a working meeting in order to consolidate the position. It has to be underlined that the directions and guidelines included in the Consensus are not the arbitrarily assumed rules of conduct in a legal aspect and as such every doctor/team of doctors is entitled to make different decisions as long as they are beneficial to a patient with gastric cancer. The Consensus discusses as follows: a) recommended qualifications (stage of advancement, pathological, lymph node topography and the extent of lymphadenectomy, division of cancer of the gastroesophageal junction), b) rules for diagnostics including recommendations regarding endoscopic examination and clinical evaluation of the advancement stage, c) recommendations regarding surgical treatment (extent of resection, extent of lymphadenectomy, tactics of proceedings in cancer of the gastroesophageal junction), d) recommendations regarding combined treatment with chemotherapy or radiotherapy, e) place of endoscopic and less invasive surgery in the treatment of gastric cancer. This publication is a summary of the arrangements made in the panel session during the abovementioned scientific symposium in Cracow in 2016.

Evaluation of serum microRNA biomarkers for gastric cancer based on blood and tissue pools profiling: the importance of miR-21 and miR-331.

BACKGROUND: High stability and disease-specific disarrangements suggest that microRNA molecules (miRNAs) present in body fluids are ideally suited for diagnostic applications, including gastric cancer (GC). However, the actual source of circulating miRNA biomarkers in GC has not been adequately evaluated, particularly in the Western populations that have some distinct characteristics compared with Asian patients. METHODS: Twenty treatment-naive patients with GC along with 20 cancer-free controls were recruited. miRCURY LNA miRNA microarrays were used for miRNA expression profiling in primary tumours and adjacent healthy mucosa. Differentially expressed serum miRNAs were identified with a high throughput TaqMan OpenArray technology in tumour-draining veins of the portal system, as well as peripheral blood of the patients and controls. RESULTS: Tissue profiling identified 108 sequences differentially expressed between primary tumours and adjacent mucosa (87 upregulated and 21 downregulated). Twenty miRNAs found in serum of GC patients showed expression levels higher than in controls. However, only seven of these molecules were overexpressed in primary tumours (miR-130a, miR-331, miR-19a, miR-223, miR-106a, miR-21, and miR-374). Moreover, expression of miR-331 and miR-21 was significantly higher in the peripheral circulation compared to tumour-draining veins of the portal system. CONCLUSIONS: The results indicate that the majority of potential serum miRNA biomarkers may originate from tissues other than the primary tumour.

Glycosylation Changes in Serum Proteins Identify Patients with Pancreatic Cancer.

After more than a decade of biomarker discovery using advanced proteomic and genomic approaches, very few biomarkers have been involved in clinical diagnostics. Most candidate biomarkers are focused on the protein component. Targeting post-translational modifications (PTMs) in combination with protein sequences will provide superior diagnostic information with regards to sensitivity and specificity. Glycosylation is one of the most common and functionally important PTMs. It plays a central role in many biological processes, including protein folding, host-pathogen interactions, immune response, and inflammation. Cancer-associated aberrant glycosylation has been identified in various types of cancer. Expression of cancer-specific glycan epitopes represents an excellent opportunity for diagnostics and potentially specific detection of tumors. Here, we report four proteins (LIFR, CE350, VP13A, HPT) found in sera from pancreatic cancer patients carrying aberrant glycan structures as compared to those of controls.

Prognostic Implications of Expression Profiling for Gemcitabine-Related Genes (hENT1, dCK, RRM1, RRM2) in Patients With Resectable Pancreatic Adenocarcinoma Receiving Adjuvant Chemotherapy.

OBJECTIVES: The aim of this study was to examine the relevance of expression profiling of 4 genes involved in the action of gemcitabine among patients with pancreatic ductal-cell adenocarcinoma (PDAC). METHODS: A group of 100 patients who underwent pancreatic resections for PDAC and received adjuvant chemotherapy with gemcitabine between 2007 and 2010 was identified. Expression of mRNAs for human equilibrative nucleoside transporter 1 (hENT1), ribonucleotide reductase subunits (RRM1, RRM2), and deoxycytidine kinase (dCK) was examined by quantitative real-time polymerase chain reaction, normalized to glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and dichotomized into groups of low and moderate/high expression levels grouped by tertiles. RESULTS: Significantly better median survival times were found for high/moderate expression levels of hENT1 (27.9 vs 12.4 months, P = 0.001) and dCK (19.7 vs 10.5 months, P = 0.003), as well as low expression of RRM1 (23.4 vs 11.4 months, P = 0.027). A Cox proportional hazards model identified low expression of hENT1 (hazard ratio [HR], 3.38; 95% confidence intervals [CI], 2.28-10.50) and dCK (HR, 2.24; 95% CI, 1.63-3.39), and high/moderate levels of RRM1 (HR, 1.65; 95% CI, 1.23-2.45) as negative prognostic factors. CONCLUSIONS: Expression of hENT, RRM1, and dCK genes provides important prognostic information for PDAC patients treated with adjuvant gemcitabine.

Preoperative Neutrophil-Lymphocyte and Lymphocyte-Monocyte Ratios Reflect Immune Cell Population Rearrangement in Resectable Pancreatic Cancer.

BACKGROUND: Neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), and lymphocyte-monocyte ratio (LMR) may serve as a simple index of the immune function. The aim of this study was to investigate the prognostic significance of NLR, PLR, and LMR in patients with resectable pancreatic ductal adenocarcinoma (PDAC) and to verify whether such biomarkers are associated with changes in populations of lymphoid cells. METHODS: The prognostic implications of blood count parameters were evaluated in a retrospective cohort of 442 subjects undergoing pancreatic resections for PDAC. Subpopulations of lymphocytes and monocytes in peripheral blood were identified by FACS in a prospective cohort of 54 patients. RESULTS: In the univariate analysis, NLR < 5 and LMR ≥ 3 were associated with significantly longer median survival of 25.7 vs 12.6 months and 29.2 vs 13.1 months, respectively. PLR did not influence survival. The Cox proportional hazards model showed that high NLR (HR 1.66, 95 % CI 1.12 to 2.46, P = 0.012) and low LMR (HR 1.65, 95 % CI 1.06 to 2.58, P = 0.026) were independent predictors of poor prognosis. NLR ≥ 5 and LMR < 3 correlated with an approximately twofold decrease in counts of helper and cytotoxic T cells, B cells, and NK cells. High NLR was also accompanied with increased neutrophil counts, while low LMR showed increased numbers of monocytes, mostly classical. CONCLUSIONS: NLR and LMR may carry important prognostic information for patients with resected PDAC. The unfavorable prognosis likely correlates with reduced numbers of immune cells effective against the tumor and increased populations of cells involved in immune suppression.

Alternative staging of regional lymph nodes in gastric cancer.

The TNM pN stage based on the number of metastatic lymph nodes is an independent prognostic factor in gastric cancer. Many studies have highlighted the phenomenon of stage migration and problems in comparing groups of patients with different numbers of total lymph nodes harvested within TNM staging. The current version of UICC/AJCC and JGCA TNM classifications postulates a minimal number of 16 lymph nodes as the base for N stage determination. Alternative systems such as lymph node ratio (LNR), positive to negative lymph node ratio (PNLNR), and LOGODDS (or LODDS), were implemented to increase the quality of LN assessment. These methods have reached the background in the literature, but to date no standard approach according to the cut-offs for the stages has been implemented. LOGODDS is the method that most reflects the number of harvested lymph nodes. The rationale for alternative staging methods, their correlations, and limitations are presented.

Factors predicting adequate lymph node yield in patients undergoing pancreatoduodenectomy for malignancy.

BACKGROUND: Most pancreatoduodenectomy resections do not meet the minimum of 12 lymph nodes recommended by the American Joint Committee on Cancer for accurate staging of periampullary malignancies. The purpose of this study was to investigate factors affecting the likelihood of adequate nodal yield in pancreatoduodenectomy specimens subject to routine pathological assessment. METHODS: Six hundred sixty-two patients subject to pancreatoduodenectomy between 1990 and 2013 for pancreatic, ampullary, and common bile duct cancers were reviewed. Predictors of yielding at least 12 lymph nodes were evaluated with a logistic regression model, and a survival analysis was carried out to verify the prognostic implications of nodal counts. RESULTS: The median number of evaluated nodes was 17 (interquartile range 11 to 25), and less than 12 lymph nodes were reported in surgical specimens of 179 (27 %) patients. Tumor diameter ≥20 mm (odds ratio [OR] 2.547, 95 % confidence interval [CI] 1.225 to 5.329, P = 0.013), lymph node metastases (OR 2.642, 95 % CI 1.378 to 5.061, P = 0.004), and radical lymphadenectomy (OR 5.566, 95 % CI 2.041 to 15.148, P = 0.01) were significant predictors of retrieving 12 or more lymph nodes. Lymph node counts did not influence the overall prognosis of the patients. However, a subgroup analysis carried out for individual cancer sites demonstrated that removing at least 12 lymph nodes is associated with better prognosis for pancreatic cancer. CONCLUSIONS: Few variables affect adequate nodal yield in pancreatoduodenectomy specimens subject to routine pathological assessment. Considering the ambiguities related to the only modifiable factor identified, appropriate pathology training should be considered to increase nodal yield rather than more aggressive lymphatic dissection.

Semiquantitative immunohistochemistry for mucin (MUC1, MUC2, MUC3, MUC4, MUC5AC, and MUC6) profiling of pancreatic ductal cell adenocarcinoma improves diagnostic and prognostic performance.

AIMS: Mucin (MUC) glycoproteins are involved in various steps of the carcinogenesis and progression of human malignancies. The aim of this study was to verify whether semiquantitative evaluation of MUC staining by immunohistochemistry may help to differentiate pancreatic ductal cell adenocarcinoma (PDAC) from chronic pancreatitis and normal pancreas. METHODS AND RESULTS: Mucin expression was examined by immunohistochemistry in surgical specimens resected from 101 patients with PDAC and 33 with chronic pancreatitis, and in 40 normal pancreatic tissue specimens. A quickscore (QS, range 0-300) was calculated by multiplying staining intensity by the percentage of positive cells. A diagnostic model was developed for MUC QS (MUC1, MUC2, MUC3, MUC4, MUC5AC, and MUC6), based on a receiver operating characteristic (ROC) curve and logistic regression analysis. Median QS values for MUC1 and MUC5AC were significantly higher for PDAC, whereas patients with non-malignant tissues had higher values for MUC3 and MUC6. The area under the curve for the ROC curve derived from the diagnostic model including MUC3, MUC5AC and MUC6 was 0.96 [95% confidence interval (CI) 0.91-0.98], with 85% sensitivity and 94% specificity. Median QS values for MUC2 were significantly higher in patients with less advanced tumours, whereas venous invasion was associated with a lower QS for MUC6. Moreover, multivariate survival analysis revealed that low MUC6 expression was a negative prognostic factor, with a hazard ratio of 1.73 (95% CI 1.07-2.81). CONCLUSIONS: The three-MUC diagnostic model (MUC3, MUC5AC, and MUC6) showed an excellent ability to discriminate pancreatic cancer from non-malignant tissues, and yielded information that may prove useful for the development of clinical applications.

Preoperative serum chemokine (C-C motif) ligand 2 levels and prognosis in colorectal cancer.

INTRODUCTION: Chemokines are cytokines with chemotactic functions in the initiation and maintenance of immune reactions. They have also been shown to regulate other processes such as cancer progression and cancer cell migration. OBJECTIVES: The aim of this study was to determine the prognostic role of serum levels of chemokine (C-C motif) ligand 2 (CCL2) and chemokine (C-C motif) ligand 5 (CCL5) in patients with colorectal cancer. PATIENTS AND METHODS: The study included a group of 45 patients with colorectal cancer. The serum concentrations of CCL2 and CCL5 were measured preoperatively. Peripheral blood mononuclear cells (PBMC) from patients' blood were isolated and cultured alone or with cancer cells. The concentrations of chemokines in serum and culture supernatants were measured using the cytometric bead array method. The cut-off points for serum chemokine levels were set based on the receiver-operating characteristic curve analysis at a level of 103.6 pg/ml for CCL2 and of 11933.2 pg/ml for CCL5. The survival analysis and multivariate analysis of prognostic factors were performed. RESULTS: The 5-year survival was 57.5% for the group with low CCL2 levels and 23.87% for the group with high CCL2 levels. For the groups with low and high CCL5 levels, the survival was 18.3% and 49.3%, respectively. For CCL2, the survival of the low-level group was significantly better than that of the highlevel group (P = 0.0028). In the Cox proportional hazard model, radicality of resection (P = 0.001) and CCL2 levels (P = 0.029) were independent prognostic factors. CONCLUSIONS: The serum level of CCL2 in patients with colorectal cancer may have prognostic value. One of the possible mechanisms of CCL2 production is the interaction of PBMC with cancer cells.

Mondor's disease in a patient after a mammotome biopsy.

Mondor's disease is a rare, benign condition characterised by thrombophlebitis affecting subcutaneous veins of the chest and/or abdomen without an accompanying inflammatory response. The disease has a multifactorial etiology and its course is benign. It is usually self-limiting or it is eliminated by local treatment. Mondor's disease in the thoracoepigastric region may be a rare complication of mammotome biopsy. The case presentation describes a 32-year-old patient with Mondor's disease in the thoracoepigastric region after an ultrasound-guided mammotome biopsy of a breast. In the histopathological examination the lesion was diagnosed as fibroadenoma. Regardless of the disease's etiology, it is recommended to carry out diagnostic examinations to exclude co-occurring breast cancer.

Carbon dioxide insufflation during screening unsedated colonoscopy: a randomised clinical trial.

One of the methods used to reduce pain and discomfort during colonoscopy is insufflation of carbon dioxide instead of air. However, the actual benefit of carbon dioxide insufflation is not unequivocally proven. The aim of the study was to evaluate the advantages of carbon dioxide insufflation during screening colonoscopy. A total of 200 patients undergoing screening colonoscopy between 2010 and 2011 were included in the prospective, randomized study carried out in a surgical referral center. Screening unsedated colonoscopy with either air or carbon dioxide insufflation was performed; patients were randomly assigned to air or carbon dioxide group by means of computer-generated randomization lists. All examinations were performed in an ambulatory setting with standard videocolonoscopes. The main outcomes analyzed were (a) duration of the entire procedure, (b) cecal intubation time, and (c) pain severity immediately, 15, and 60 min after the procedure. Group I included 59 women and 41 men and group II included 51 women and 49 men. The duration of the procedure was circa 10 min in both groups. Pain score values immediately and 15 min after the procedure were similar in both groups (P=0.624 and 0.305, respectively). A lower pain score was observed only after 60 min in patients insufflated with carbon dioxide (1.28 vs. 1.54, P=0.008). No pain reduction was observed in women and in obese patients (BMI>30). Carbon dioxide insufflation during unsedated screening colonoscopy does not decrease the duration of the procedure and appears to reduce pain intensity at 60 min after examination to an extent without clinical significance. The study was registered at ClinicalTrials.gov, number NCT01461564.