Enhancing endoscopic measurement: validating a quantitative method for polyp size and location estimation in upper gastrointestinal endoscopy.

BACKGROUND: Accurate measurement of polyps size is crucial in predicting malignancy, planning relevant intervention strategies and surveillance schedules. Endoscopists' visual estimations can lack precision. This study builds on our prior research, with the aim to evaluate a recently developed quantitative method to measure the polyp size and location accurately during a simulated endoscopy session. METHODS: The quantitative method merges information about endoscopic positions obtained from an electromagnetic tracking sensor, with corresponding points on the images of the segmented polyp border. This yields real-scale 3D coordinates of the border of the polyp. By utilising the sensor, positions of any anatomical landmarks are attainable, enabling the estimation of a polyp's location relative to them. To verify the method's reliability and accuracy, simulated endoscopies were conducted in pig stomachs, where polyps were artificially created and assessed in a test-retest manner. The polyp measurements were subsequently compared against clipper measurements. RESULTS: The average size of the fifteen polyps evaluated was approximately 12 ± 4.3 mm, ranging from 5 to 20 mm. The test-retest reliability, measured by the Intraclass Correlation Coefficient (ICC) for polyp size estimation, demonstrated an absolute agreement of 0.991 (95% CI 0.973-0.997, p < 0.05). Bland & Altman analysis revealed a mean estimation difference of - 0.17 mm (- 2.03%) for polyp size and, a mean difference of - 0.4 mm (- 0.21%) for polyp location. Both differences were statistically non-significant (p > 0.05). When comparing the proposed method with calliper measurements, the Bland & Altman plots showed 95% of size estimation differences between - 1.4 and 1.8 mm (- 13 to 17.4%) which was not significant (p > 0.05). CONCLUSIONS: The proposed method of measurements of polyp size and location was found to be highly accurate, offering great potential for clinical implementation to improve polyp assessment. This level of performance represents a notable improvement over visual estimation technique used in clinical practice.

Endoscopic measurement of the size of gastrointestinal polyps using an electromagnetic tracking system and computer vision-based algorithm.

PURPOSE: Polyp size is an important factor that may influence diagnosis and clinical management decision, but estimation by visual inspection during endoscopy is often difficult and subject to error. The purpose of this study is to develop a quantitative approach that enables an accurate and objective measurement of polyp size and to study the feasibility of the method. METHODS: We attempted to estimate polyp size and location relative to the gastro-oesophageal junction by integrating data from an electromagnetic tracking sensor and endoscopic images. This method is based on estimation of the three-dimensional coordinates of the borders of the polyp by combining the endoscope camera position and the corresponding points along the polyp border in endoscopic images using a computer vision-based algorithm. We evaluated the proposed method using a simulated upper gastrointestinal endoscopy model. RESULTS: The difference between the mean of ten measurements of one artificial polyp and its actual size (10 mm in diameter) was 0.86 mm. Similarly, the difference between the mean of ten measurements of the polyp distance from the gastroesophageal junction and its actual distance (~ 22 cm) was 1.28 mm. Our results show that the changes in camera positions in which the images were taken and the quality of the polyp segmentation have the most impact on the accuracy of polyp size estimation. CONCLUSION: This study demonstrated an innovative approach to endoscopic measurements using motion tracking technologies and computer vision and demonstrated its accuracy in determining the size and location of the polyp. The observed magnitude of error is clinically acceptable, and the measurements are available immediately after the images captured. To enhance accuracy, it is recommended to avoid identical images and instead utilise control wheels on the endoscope for capturing different views. Future work should further evaluate this innovative method during clinical endoscopic procedures.

Prevalence and Sonographic Detection of Gallbladder Polyps in a Western European Population.

BACKGROUND: Gallbladder cancer is rare but associated with significant morbidity and mortality necessitating the early identification of premalignant and malignant lesions to improve overall prognosis. Despite limited evidence regarding the effectiveness of transabdominal ultrasound (US) in the detection of gallbladder polyps, it plays a key role in current European guidelines. The aim of this study was to investigate gallbladder polyp prevalence in a western European population and assess the diagnostic accuracy of transabdominal US. METHODS: Data from patients who underwent cholecystectomy for US detected gallbladder polypoid lesions at four hospitals in Ireland and the United Kingdom between 2010 and 2018 were retrospectively collected. Patient demographics, ultrasonographic, and histopathologic findings were analyzed. RESULTS: A total of 134 patients underwent cholecystectomy for US-detected gallbladder polyps. After histopathologic examination, pseudopolyps were found in 75 (56%) specimens with dysplastic or malignant polyps seen in only six (4.5%) specimens. Mean size for neoplastic polyps was 33 mm. The positive predictive value for US in detecting neoplastic polyps in this study was 4.5%, which is significantly lower than the 10%-15% reported previously. CONCLUSIONS: Although the prevalence of neoplastic polyps in this study is higher than in the previous literature, the distribution of pseudopolyps and true polyps is as expected. With all malignant polyps being >10 mm in diameter, these findings support the current size thresholds stated in European guidelines. The poor diagnostic accuracy of US demonstrated may have led to significant number of patients undergoing unnecessary surgical intervention, further supporting the argument for improved strategies for the investigation of gallbladder polyps.

Open and laparoscopically assisted oesophagectomy: a prospective comparative study.

OBJECTIVES: Although a number of studies have examined minimally invasive approaches for oesophagectomy, these procedures have typically been offered only to selected patients with the limited long-term follow-up data. The purpose of this prospective study was to assess the feasibility of performing laparoscopically assisted oesophagectomy (LAO) for all-comers and to compare the short- and long-term clinical outcomes of this surgical strategy with a matched cohort of patients who had undergone open surgery. METHODS: From November 2009, all patients referred for trans-thoracic resection of an oesophageal cancer underwent a two-stage laparoscopically assisted Ivor-Lewis oesophagectomy. This consisted of laparoscopic mobilization of the stomach and distal oesophagus, followed by open thoracotomy, thoracic lymphadectomy and intrathoracic anastomosis. The clinical and oncological outcomes of the first 39 consecutive LAO patients were compared with those of the preceding 31 consecutive patients who had undergone open surgery. RESULTS: Of the 39 LAO cases, 37 cases were completed laparoscopically and 2 were converted to an open surgery. LAO was associated with a decreased incidence of postoperative complications (specifically cardiac and infectious complications) when compared with open surgery (54 vs 77%, P = 0.04). In addition, the initial intensive care unit stay (2 vs 4 days; P = 0.04) and overall length of hospital stay (14 vs 18 days; P = 0.02) were shorter in the LAO group. In terms of pathological outcomes, the lymph node yield and R0 resection rate of the LAO and open groups were comparable, as were the 1-year survival rates (62 vs 61%, P = 0.97). CONCLUSIONS: LAO can be offered to an unselected cohort of all-comers with a reduced postoperative complication rate and comparable oncological and long-term survival outcomes when compared with open surgery.

Long-term outcomes of extended proximal gastrectomy for oesophagogastric junctional tumours.

BACKGROUND: There is no consensus on the optimum approach for resection of oesophagogastric junctional (OGJ) tumours. We prospectively evaluated the efficacy of transabdominal radical extended proximal gastrectomy with oesophagogastric anastomosis (EPGOG) for selected tumours of the OGJ. METHODS: Between 1998 and 2007, 66 selected consecutive patients with tumours of the OGJ underwent successful EPGOG. Selection was limited to tumours where the maximal proximal extent was 36 cm ab oral. Pre-, peri-, and postoperative outcomes together with long-term survival data for these patients were prospectively collected. RESULTS: Median theatre time was 242 min (range = 120-480), with a median blood loss of 300 ml (range = 50-1720). Eighty-nine percent of patients were extubated in theatre; major complications occurred in 9 (14%) patients, with an overall in-hospital mortality rate of 8%. Thirty-five (53%) patients had nodal disease and the median lymph node yield was 13 (range = 4-36), with an R0 resection rate of 80%. In terms of long-term outcomes, the 2- and 5-year actuarial survival rates were 54 ± 6% and 41 ± 6%. CONCLUSION: Extended radical proximal gastrectomy with oesophagogastric anastomosis for selected junctional tumours is a feasible technique which does not compromise oncological principles as evidenced by an excellent long-term survival rate.

Is an involved circumferential resection margin following oesphagectomy for cancer an important prognostic indicator?

A best evidence topic in thoracic surgery was written according to a structured protocol. The question addressed was whether an involved circumferential resection margin (CRM) following oesophagectomy for cancer is an independent predictor of poor long-term survival. Six hundred and fourteen papers were found using the reported search, of which seven represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group, study type, relevant outcomes and results of these papers are tabulated. Of these studies, four were conducted on patients who predominantly did not receive preoperative chemotherapy and showed conflicting results as to the prognostic significance of CRM involvement. However, three later studies conducted on patients who predominantly did receive preoperative chemotherapy showed that CRM involvement to be an independent predictor of long-term survival. We conclude that for patients who undergo oesophagectomy alone as a treatment for oesophageal cancer, the prognostic importance of CRM involvement is unclear. However, for patients who undergo preoperative chemotherapy prior to surgery, there does appear to be emerging evidence supporting the concept that CRM involvement is an independent predictor of poor long-term outcome.

A double-blind, randomised, controlled trial to study the effects of an enteral feed supplemented with glutamine, arginine, and omega-3 fatty acid in predicted acute severe pancreatitis.

CONTEXT: Current best evidence is in favour of early institution of enteral feeding in acute severe pancreatitis with promising results from trials in immunonutrition on other patient groups. OBJECTIVE: To identify which groups of patients and products are associated with benefit, we investigated immunonutrition in patients with predicted acute severe pancreatitis. DESIGN: A randomised trial of a study feed containing glutamine, arginine, tributyrin and antioxidants versus an isocaloric isonitrogenous control feed was undertaken. PATIENTS: Thirty-one patients with a diagnosis of acute pancreatitis predicted to develop severe disease: 15 study feeds and 16 control feeds. INTERVENTIONS: Enteral feeding via nasojejunal tube for 3 days. If patients required further feeding the study was continued up to 15 days. MAIN OUTCOME MEASURES: Reduction in C-reactive protein (CRP) by 40 mg/L after 3 days of enteral feeding was the primary endpoint. Carboxypeptidase B activation peptide (CAPAP) levels were taken at regular intervals. RESULTS: After 3 days of feeding, in the study group 2/15 (13%) of patients had reduced their CRP by 40 mg/L or more. In the control group 6/16 (38%) of patients had reduced their CRP by this amount. This difference was found to be near the statistical significant limit (P=0.220). CONCLUSIONS: The cause of the unexpectedly higher CRP values in the study group is unclear. The rise in CRP was without a commensurate rise in CAPAP or outcome measures so there was no evidence that this represented pancreatic necrosis. The contrast between the CRP and CAPAP results is of interest and we believe that specific pancreatic indices such as CAPAP should be considered in larger future studies.

Cancer cell adaptation to chemotherapy.

BACKGROUND: Tumor resistance to chemotherapy may be present at the beginning of treatment, develop during treatment, or become apparent on re-treatment of the patient. The mechanisms involved are usually inferred from experiments with cell lines, as studies in tumor-derived cells are difficult. Studies of human tumors show that cells adapt to chemotherapy, but it has been largely assumed that clonal selection leads to the resistance of recurrent tumors. METHODS: Cells derived from 47 tumors of breast, ovarian, esophageal, and colorectal origin and 16 paired esophageal biopsies were exposed to anticancer agents (cisplatin; 5-fluorouracil; epirubicin; doxorubicin; paclitaxel; irinotecan and topotecan) in short-term cell culture (6 days). Real-time quantitative PCR was used to measure up- or down-regulation of 16 different resistance/target genes, and when tissue was available, immunohistochemistry was used to assess the protein levels. RESULTS: In 8/16 paired esophageal biopsies, there was an increase in the expression of multi-drug resistance gene 1 (MDR1) following epirubicin + cisplatin + 5-fluorouracil (ECF) chemotherapy and this was accompanied by increased expression of the MDR-1 encoded protein, P-gp. Following exposure to doxorubicin in vitro, 13/14 breast carcinomas and 9/12 ovarian carcinomas showed >2-fold down-regulation of topoisomerase IIalpha (TOPOIIalpha). Exposure to topotecan in vitro, resulted in >4-fold down-regulation of TOPOIIalpha in 6/7 colorectal tumors and 8/10 ovarian tumors. CONCLUSION: This study suggests that up-regulation of resistance genes or down-regulation in target genes may occur rapidly in human solid tumors, within days of the start of treatment, and that similar changes are present in pre- and post-chemotherapy biopsy material. The molecular processes used by each tumor appear to be linked to the drug used, but there is also heterogeneity between individual tumors, even those with the same histological type, in the pattern and magnitude of response to the same drugs. Adaptation to chemotherapy may explain why prediction of resistance mechanisms is difficult on the basis of tumor type alone or individual markers, and suggests that more complex predictive methods are required to improve the response rates to chemotherapy.

Rapid up-regulation of cyclooxygenase-2 by 5-fluorouracil in human solid tumors.

Inhibition of cyclooxygenase (COX)-2 has been associated with reduced growth of malignant cells. Current therapy of gastrointestinal carcinomas involves the use of 5-fluorouracil (5-FU)-based chemotherapy and we have therefore studied the effect of this agent on the expression of COX-2. COX-2 expression was measured by quantitative RT-PCR in biopsies from a series of 14 esophageal carcinomas, six of which had paired samples taken before and after chemotherapy, and in tumor-derived cells exposed to 5-FU in vitro from a series of 44 tumors, including breast, ovarian, esophageal and colonic carcinomas. COX-2 expression was increased by exposure to 5-FU or 5-FU combination chemotherapy in all the tumor types studied, whether measured in biopsies taken before and after 5-FU-based chemotherapy (4-fold increase, p<0.015) or in primary cells exposed to drugs in vitro (24-fold increase, p<0.001). A modest increase of COX-2 mRNA was also seen after in vitro treatment of cells with cisplatin. In contrast, doxorubicin and paclitaxel caused no up-regulation in vitro, while irinotecan caused inhibition of COX-2 (2.7-fold decrease, p<0.01). These data provide a molecular rationale for clinical trials of combination chemotherapy with COX-2 inhibitors.

Heterogeneity of chemosensitivity of esophageal and gastric carcinoma.

Esophageal and gastric cancer have a poor prognosis, and chemotherapy is rarely of long-term benefit. This may be related in part to heterogeneity of chemosensitivity and to constitutive resistance to individual cytotoxic drugs. This study aimed to demonstrate the degree of heterogeneity of chemosensitivity between tumors. We have examined the heterogeneity of chemosensitivity in esophageal and gastric cancer specimens (n=85) using an ex vivo ATP-based chemosensitivity assay (ATP-TCA). A variety of chemotherapeutic agents were tested. Sixty-four specimens were endoscopic biopsy samples; the remainder were from resection specimens. Cells were obtained from 62 specimens (73%). Eight assays were infected due to contamination/infection of the biopsy material, giving an evaluability rate of 87%. Analysis of the data showed considerable heterogeneity of chemosensitivity. The most active single agents identified by the assay were mitomycin C (56% sensitivity) and 5-fluorouracil (5-FU; 42% sensitivity). Exposure of tumor cells to combinations of drugs showed ECF (epirubicin, cisplatin, 5-FU) and mitomycin C+5-FU to be moderately active regimens. Other experimental drug combinations showed greater activity. There is a marked heterogeneity of chemosensitivity in esophageal and gastric cancers. The degree of heterogeneity observed suggests that the ATP-TCA could be used to individualize chemotherapy by selecting agents for particular patients. This approach provides the rationale for a trial of ATP-TCA-directed therapy to determine whether individualization of chemotherapy might improve patient response and survival.