Explore the vast range of titles available.

Background Artificial intelligence (AI) is increasingly being used in medical imaging analysis. We aimed to evaluate the diagnostic accuracy of AI models used for detection of lymph node metastasis on pre-operative staging imaging for colorectal cancer. Methods A systematic review was conducted according to PRISMA guidelines using a literature search of PubMed (MEDLINE), EMBASE, IEEE Xplore and the Cochrane Library for studies published from January 2010 to October 2020. Studies reporting on the accuracy of radiomics models and/or deep learning for the detection of lymph node metastasis in colorectal cancer by CT/MRI were included. Conference abstracts and studies reporting accuracy of image segmentation rather than nodal classification were excluded. The quality of the studies was assessed using a modified questionnaire of the QUADAS-2 criteria. Characteristics and diagnostic measures from each study were extracted. Pooling of area under the receiver operating characteristic curve (AUROC) was calculated in a meta-analysis. Results Seventeen eligible studies were identified for inclusion in the systematic review, of which 12 used radiomics models and five used deep learning models. High risk of bias was found in two studies and there was significant heterogeneity among radiomics papers (73.0%). In rectal cancer, there was a per-patient AUROC of 0.808 (0.739–0.876) and 0.917 (0.882–0.952) for radiomics and deep learning models, respectively. Both models performed better than the radiologists who had an AUROC of 0.688 (0.603 to 0.772). Similarly in colorectal cancer, radiomics models with a per-patient AUROC of 0.727 (0.633–0.821) outperformed the radiologist who had an AUROC of 0.676 (0.627–0.725). Conclusion AI models have the potential to predict lymph node metastasis more accurately in rectal and colorectal cancer, however, radiomics studies are heterogeneous and deep learning studies are scarce. Trial registration PROSPERO CRD42020218004 .

Purpose Prolonged post-operative ileus (PPOI) increases post-operative morbidity and prolongs hospital stay. An improved understanding of the elements which contribute to the genesis of PPOI is needed in the first instance to facilitate accurate risk stratification and institute effective preventive measures. The aim of this retrospective cohort study was to therefore determine the perioperative risk factors associated with development of PPOI. Methods All elective intra-abdominal operations undertaken by the Colorectal Unit at Auckland District Health Board from 1 January to 31 December 2011 were accessed. Data were extracted for an assortment of patient characteristics and perioperative variables. Cases were stratified by the occurrence of clinician-diagnosed PPOI. Univariate and regression analyses were performed to identify correlates and independent risk factors, respectively. Results Two hundred and fifty-five patients were identified of whom 50 (19.6 %) developed PPOI. The median duration for PPOI was 4 days with 98 % resolving spontaneously with conservative measures. Univariate analysis identified increasing age; procedure type; increasing opiate consumption; elevated preoperative creatinine; post-operative haemoglobin drop, highest white cell count and lowest sodium; and increasing complication grade as significant correlates. Logistic regression found increasing age (OR 1.032, 95 % CI 1.004–1.061; p  = 0.026) and increasing drop in pre- to post-operative haemoglobin (OR 1.043, 95 % CI 1.002–1.085; p  = 0.037) as the only independent predictors for developing PPOI. An important limitation of this study was its retrospective nature. Conclusions Increasing age and increasing drop in haemoglobin are independent predictors for developing PPOI. Prospective assessment is required to facilitate more accurate risk factor analysis.

Background The most important prognostic factor in colonic cancer is the presence or absence of regional lymph nodes metastases. The aim of this study was to evaluate the relationship between 5-year mortality in the New Zealand population, and the number of nodes examined in Stage II and III colon cancers. Methods New Zealand Cancer Registry data were retrieved for patients with colonic cancer from January 1995 to July 2003. Patients with incomplete entries, Stage I tumors, and distant metastases were excluded from analysis. Univariate and Cox regression models were used with 5-year mortality as the primary endpoint. Results The study identified 4309 patients. Younger age, female gender, Pacific Island descent, and right-sided tumors were associated with significantly higher lymph node retrieval. Cox regression analysis showed that the number of nodes examined was a significant predictor of 5-year mortality when age, sex, ethnicity, and site were controlled for. Five-year survival consistently improved between nodal strata until the 16-node mark, above which survival advantage was minimal. For Stage III cancers, a higher lymph node ratio was associated with a significant increase in mortality. Conclusions Increased rates of nodal examination are associated with a significantly lower 5-year mortality for Stage II and III colonic cancer, but this survival advantage appears to be minimal after the 16-node mark. The lymph node ratio has been validated as a powerful predictor of survival in Stage III cancer. Our results support the current practice of harvesting and examining as many nodes as possible during attempted curative resection.

Background There is a lack of an internationally accepted standardised clinical definition for postoperative ileus (POI). This has made it difficult to estimate incidence and identify risk factors and has compromised external validity of clinical trials. Aim To clarify terminology of POI and propose concise, clinically quantifiable definitions. Methods A systematic review extracted definitions from randomised trials published between 1996 and 2011 investigating POI after abdominal surgery. This was followed by a global survey seeking opinions of those who have published in the field. Results Definitions were extracted from 52 identified trials. Responses were received in the survey from 45 of 118 corresponding authors. Data were amalgamated to synthesise the following definitions: postoperative ileus (POI) “interval from surgery until passage of flatus/stool AND tolerance of an oral diet”; prolonged POI “two or more of nausea/vomiting, inability to tolerate oral diet over 24 h, absence of flatus over 24 h, distension, radiologic confirmation occurring on or after day 4 postoperatively without prior resolution of POI”; recurrent POI “two or more of nausea/vomiting, inability to tolerate oral diet over 24 h, absence of flatus over 24 h, distension, radiologic confirmation, occurring after apparent resolution of POI”. Concordance of the latter two definitions with survey responses were ≥75 %. Conclusion We have proposed standardised endpoints for use in future studies to facilitate objective comparison of competing interventions.

Aim Prolonged postoperative ileus (PPOI) occurs in around 15% of patients after major abdominal surgery, posing a significant clinical and economic burden. Significant fluid and electrolyte changes may occur peri‐operatively, potentially contributing to PPOI; however, this association has not been clearly elucidated. A joint clinical‐theoretical study was undertaken to evaluate peri‐operative electrolyte concentration trends, their association with ileus, and predicted impact on bioelectrical slow waves in interstitial cells of Cajal (ICC) and smooth muscle cells (SMC). Methods Data were prospectively collected from 327 patients undergoing elective colorectal surgery. Analyses were performed to determine associations between peri‐operative electrolyte concentrations and prolonged ileus. Biophysically based ICC and SMC mathematical models were adapted to evaluate the theoretical impacts of extracellular electrolyte concentrations on cellular function. Results Postoperative day (POD) 1 calcium and POD 3 chloride, sodium were lower in the PPOI group (p < 0.05), and POD3 potassium was higher in the PPOI group (p < 0.05). Deficits beyond the reference range in PPOI patients were most notable for sodium (Day 3: 29.5% ileus vs. 18.5% no ileus, p = 0.04). Models demonstrated an 8.6% reduction in slow‐wave frequency following the measured reduction in extracellular NaCl on POD5, with associated changes in cellular slow‐wave morphology and amplitude. Conclusion Low serum sodium and chloride concentrations are associated with PPOI. Electrolyte abnormalities are unlikely to be a primary mechanism of ileus, but their pronounced effects on cellular electrophysiology predicted by modeling suggest these abnormalities may adversely impact motility recovery. Resolution and correction of electrolyte abnormalities in ileus may be clinically relevant.

Several clinical guidelines exist for acute pancreatitis, with varying recommendations. The aim of this study was to determine the quality of guidelines for acute pancreatitis. A literature search identified relevant guidelines, which were then reviewed to determine their document format and scope and the presence of endorsement by a professional body. The quality of guidelines was determined using the validated Grilli, Shaneyfelt, and AGREE instruments. Twenty-one of the 30 guidelines analyzed were endorsed by professional bodies. Median quality scores were as follows: Grilli, 2; Shaneyfelt, 13; and AGREE, 50. Guideline quality did not improve over time. Guidelines endorsed by a professional body had higher scores than those without official endorsement. Guidelines with tables, a recommendations summary, evidence grading, and audit goals had significantly higher scores than guidelines lacking those features. The many clinical guidelines for acute pancreatitis range widely in quality. Guidelines developed by professional bodies, and those with tables, a recommendations summary, evidence grading, and audit goals, are of higher quality. Further research is required to determine whether guideline quality alters clinical outcomes.

Background Cyclic motor patterns (CMPs) are the most common motor pattern in the distal colon. This study used high‐resolution (HR) colonic manometry to quantify trends in distal colonic motor activity before elective colonic surgery, determine the effect of a preoperative carbohydrate load, and compare this with a meal response in healthy controls. Methods Fiber‐optic HR colonic manometry (36 sensors, 1 cm intervals) was used to investigate distal colonic motor activity in 10 adult patients prior to elective colonic surgery, 6 of whom consumed a preoperative carbohydrate drink (200 kCal). Data were compared with nine healthy volunteers who underwent HR colonic manometry recordings while fasted and following a 700 kCal meal. The primary outcome was the percentage of recording occupied by CMPs, defined as propagating contractions at 2–4 cycles per minute (cpm). Secondary outcomes included amplitude, speed, and distance of propagating motor patterns. Results The occurrence of CMPs progressively increased in time periods closer to surgery (p = 0.001). Consumption of a preoperative drink resulted in significantly increased CMP occurrence (p = 0.04) and propagating distance (p = 0.04). There were no changes in amplitude or speed of propagating motor patterns during the preoperative period. The increase in activity following a preoperative drink was of similar magnitude to the colonic meal response observed in healthy controls, despite the lesser caloric nutrient load. Conclusion Distal colonic CMP increased in occurrence prior to surgery, amplified by ingestion of preoperative carbohydrate drinks. We hypothesize that anxiety, which is also known to rise with proximity to surgery, could play a contributing role. Distal colonic cyclic motor patterns increased in occurrence prior to surgery, amplified by ingestion of preoperative carbohydrate drinks. We hypothesize that anxiety, which is also known to rise with proximity to surgery, could play a contributing role.

Background The impact of RAS/BRAF mutation on primary response rates after total neoadjuvant therapy (TNT) in patients with advanced rectal cancer is unclear. The aim of this study was to assess complete response rates after TNT according to RAS/BRAF mutation status. Methods A prospective observational study was performed in patients with rectal cancer who underwent TNT with curative intent at three South Australian hospitals between 2019 and 2023. Patients were classified according to their mutation status: mutant RAS/BRAF (mutRAS) or wild-type RAS/BRAF (wtRAS). The primary endpoint was overall complete response (oCR) rate, defined as the proportion of patients who achieved clinical complete response (cCR) and/or pathological complete response (pCR). Results Of the 150 patients eligible for inclusion, 80 patients with RAS/BRAF status available were identified. Of these, 43 (53.8%) patients were classified as mutRAS and 37 (46.3%) patients as wtRAS. Patients with mutRAS had significantly lower cCR and oCR rates after TNT than patients with wtRAS (14% vs. 37.8%, p  = 0.014; 11.6% vs. 43.2%, p  = 0.001, respectively). There was no significant difference in pCR rate between the groups. Of the 80 rectal cancer patients tested, 35 (43.8%) had metastatic disease (M1). There was no significant difference in complete M1 response rates between the groups (17.6% vs. 38.9%, p  = 0.254). Conclusion RAS/BRAF mutations negatively impact primary tumor response rates after TNT in patients with advanced rectal cancer. Large-scale national studies are needed to determine whether RAS/BRAF status could be used to select optimal oncologic therapy in rectal cancer patients.