Machine learning prediction model for postoperative ileus following colorectal surgery.

BACKGROUND: Postoperative ileus (POI) continues to be a major cause of morbidity following colorectal surgery. Despite best efforts, the incidence of POI in colorectal surgery remains high (~30%). This study aimed to investigate machine learning techniques to identify risk factors for POI in colorectal surgery patients, to help guide further preventative strategies. METHODS: A TRIPOD-guideline-compliant retrospective study was conducted for major colorectal surgery patients at a single tertial care centre (2018-2022). The primary outcome was the occurrence of POI, defined as not achieving GI-2 (outcome measure of time to first stool and tolerance of oral diet) by day four. Multivariate logistic regression, decision trees, radial basis function and multilayer perceptron (MLP) models were trained using a random allocation of patients to training/testing data sets (80/20). The area under the receiver operating characteristic (AUROC) curves were used to evaluate model performance. RESULTS: Of 504 colorectal surgery patients, 183 (36%) experienced POI. Multivariate logistic regression, decision trees, radial basis function and MLP models returned an AUROC of 0.722, 0.706, 0.712 and 0.800, respectively. The MLP model had the highest sensitivity and specificity values. In addition to well-known risk factors for POI, such as postoperative hypokalaemia, surgical approach, and opioid use, the MLP model identified sarcopenia (ranked 4/30) as a potentially modifiable risk factor for POI. CONCLUSION: MLP outperformed other models in predicting POI. Machine learning can provide valuable insights into the importance and ranking of specific predictive variables for POI. Further research into the predictive value of preoperative sarcopenia for POI is required.

Pyridostigmine to Reduce the duration of postoperative Ileus after Colorectal surgery (PyRICo-RCT): randomized clinical trial.

BACKGROUND: Postoperative ileus, driven by the cholinergic anti-inflammatory pathway, is the most common complication in patients undergoing colorectal surgery. By inhibiting acetylcholinesterase, pyridostigmine can potentially modulate the cholinergic anti-inflammatory pathway and accelerate gastrointestinal recovery. This study aimed to assess the efficacy of pyridostigmine in improving gastrointestinal recovery after colorectal surgery. METHODS: This double-blinded RCT enrolled adult patients undergoing elective colorectal surgery at two hospitals in South Australia. Patients were randomized to 60 mg oral pyridostigmine or placebo twice daily starting 6 h after surgery until the first passage of stool. The primary outcome was GI-2, a validated composite measure of time to first stool and tolerance of oral diet. Secondary outcomes included incidence of postoperative ileus (defined as GI-2 greater than 4 days), duration of hospital stay, and 30-day complications, evaluated by intention-to-treat univariate analysis. RESULTS: Of 130 patients recruited (mean(s.d.) age 58.4(16.4) years; 73 men, 56%), 65 were allocated to each arm. The median GI-2 was 1 day shorter with pyridostigmine compared with placebo (2 (i.q.r. 1-3) versus 3 (2-4) days; P = 0.015). However, there were no significant differences in postoperative ileus (17.2 versus 21.5%; P = 0.532) or duration of hospital stay (median 5 (i.q.r. 4-8.75) versus 5 (4-7.5) days; P = 0.921). Similarly, there were no significant differences in overall complications, anastomotic leak, cardiac complications, or patient-reported side effects. CONCLUSION: Pyridostigmine resulted in a quicker return of GI-2 and was well tolerated. Larger multicentre studies are required to determine the optimal dosing and evaluate the impact of pyridostigmine in different surgical settings. Registration number: ACTRN12621000530820 (https://anzctr.org.au).

Sense of agency in joint action: a critical review of we-agency.

The sense of agency refers to the experience of control over voluntary actions and their effects. There is growing interest in the notion of we-agency, whereby individual sense of agency is supplanted by a collective agentic experience. The existence of this unique agentic state would have profound implications for human responsibility, and, as such, warrants further scrutiny. In this paper, we review the concept of we-agency and examine whether evidence supports it. We argue that this concept entails multiplying hypothetical agentic states associated with joint action, thus ending up with an entangled phenomenology that appears somewhat speculative when weighted against the available evidence. In light of this, we suggest that the concept of we-agency should be abandoned in favor of a more parsimonious framework for the sense of agency in joint action.

Use of Acetylcholinesterase Inhibitors in Reducing Time to Gastrointestinal Function Recovery following Abdominal Surgery: A Systematic Review.

INTRODUCTION: Postoperative ileus (POI) is a significant complication following abdominal surgery, increasing morbidity and mortality. The cholinergic anti-inflammatory response is one of the major pathways involved in developing POI, but current recommendations to prevent POI do not target this. This review aims to summarise evidence for the use of acetylcholinesterase inhibitors, neostigmine and pyridostigmine, to reduce the time to return of gastrointestinal function (GI) following abdominal surgery. METHODS: A systematic search of various databases was performed from 1946 to May 2023. Randomised controlled trials (RCTs) on acetylcholinesterase inhibitors in intra-abdominal surgery were included. Data on time to flatus and/or stool and side effects were extracted. RESULTS: Among 776 screened manuscripts, 8 RCTs (703 patients) investigating acetylcholinesterase inhibitors in intra-abdominal surgery were analysed. Five studies showed a significant reduction in time to flatus and/or stool by 17-47.6 h. Methodological variations, differing procedure types, and potential bias were observed. Limited studies reported side effects or length of stay. CONCLUSION: Acetylcholinesterase inhibitors may reduce the time for GI to return. However, current evidence is limited and biased. Further studies incorporating acetylcholinesterase inhibitors in an enhanced recovery protocol are required to address this question, especially for patients undergoing colorectal surgery.

Deep learning to predict lymph node status on pre-operative staging CT in patients with colon cancer.

INTRODUCTION: Lymph node (LN) metastases are an important determinant of survival in patients with colon cancer, but remain difficult to accurately diagnose on preoperative imaging. This study aimed to develop and evaluate a deep learning model to predict LN status on preoperative staging CT. METHODS: In this ambispective diagnostic study, a deep learning model using a ResNet-50 framework was developed to predict LN status based on preoperative staging CT. Patients with a preoperative staging abdominopelvic CT who underwent surgical resection for colon cancer were enrolled. Data were retrospectively collected from February 2007 to October 2019 and randomly separated into training, validation, and testing cohort 1. To prospectively test the deep learning model, data for testing cohort 2 was collected from October 2019 to July 2021. Diagnostic performance measures were assessed by the AUROC. RESULTS: A total of 1,201 patients (median [range] age, 72 [28-98 years]; 653 [54.4%] male) fulfilled the eligibility criteria and were included in the training (n = 401), validation (n = 100), testing cohort 1 (n = 500) and testing cohort 2 (n = 200). The deep learning model achieved an AUROC of 0.619 (95% CI 0.507-0.731) in the validation cohort. In testing cohort 1 and testing cohort 2, the AUROC was 0.542 (95% CI 0.489-0.595) and 0.486 (95% CI 0.403-0.568), respectively. CONCLUSION: A deep learning model based on a ResNet-50 framework does not predict LN status on preoperative staging CT in patients with colon cancer.

Clinical predictors of rectal cancer response after neo-adjuvant (Chemo)Radiotherapy in Australia and New Zealand: Analysis of the Bi-National Colorectal Cancer Audit (BCCA).

Pathological complete response (pCR) is observed in 11-26% of locally advanced rectal cancers undergoing neoadjuvant chemoradiotherapy (nCRT). This study aims to determine pCR rates and clinicopathological predictors in the Australian and New Zealand (ANZ) cohort. The Bi-National Colorectal Cancer Audit (BCCA) was interrogated for all rectal cancer patients who underwent nCRT prior to surgical resection between 2007 and 2020. Patients were divided in two groups: pCR (AJCC tumour regression grade 0) and partial/no response (pPR, regression grade 1,2 or 3). In total, 3230 patients were included. Rates of pCR and pPR were 704 (21.8%) and 2526 (78.2%), respectively. Long-course nCRT (p < 0.0001), lower clinical tumour stage (cT; p < 0.0001), and nodal stage (cN; p = 0.003) were associated with pCR on univariate analysis. On multivariable analysis, cN0 stage and long-course nCRT remained independent factors for a pCR. Awareness of these predictors provides valuable information when counseling patients regarding prognosis and treatment options.

Incidence and associated morbidity of sarcopenia in non-malignant small and large bowel anastomosis: propensity score-matched analysis.

PURPOSE: Sarcopenia is a prognostic factor for poor outcomes in colorectal cancer, but data are scarce in colorectal surgery for benign conditions where patients could benefit from a deferral of surgery to enter a prehabilitation programme. We assessed the incidence of sarcopenia and complications in patients with benign colorectal disease. METHODS: Patients who underwent elective non-malignant colorectal surgery during 2018-2022 were retrospectively identified. The cross-sectional psoas area was calculated using computed tomography (CT) imaging mid-3rd lumbar vertebrae. Sarcopenia was determined using gender-specific cut-offs. The primary outcome was complications measured by the comprehensive complication index (CCI). RESULTS: Of 188 patients identified, 39 (20.7%) were sarcopenic. Patients diagnosed with sarcopenia were older (63 vs. 58 years, p = 0.047) and had a reduced BMI (24.7 vs. 27.38 kg/m2, p = 0.001). Sarcopenic patients had more complications (82.1 vs. 64.4%, p = 0.036), and CCI was statistically but not clinically higher (20.9 vs. 20.9, p = 0.047). On univariate linear regression analysis, age ≥ 65 years old, ASA grade ≥ 3, active smokers, sarcopenia, and preoperative anaemia were predictive of CCI. Propensity score-matched analysis was performed, matching 78 cases to remove selection bias, which demonstrated sarcopenia had no impact on postoperative complications. On multivariate analysis, age (p = 0.022), smoking (p = 0.005), and preoperative anaemia (p = 0.008) remained predictive of CCI. CONCLUSION: Sarcopenia is prevalent in one-fifth of patients undergoing benign colorectal surgery. Taking advantage of the longer preoperative waiting periods, sarcopenia could be explored as a target for prehabilitation programmes to improve outcomes.

Global cost of postoperative ileus following abdominal surgery: meta-analysis.

BACKGROUND: Following abdominal surgery, postoperative ileus is a common complication significantly increasing patient morbidity and cost of hospital admission. This is the first systematic review aimed at determining the average global hospital cost per patient associated with postoperative ileus. METHODS: A systematic search of electronic databases was performed from January 2000 to March 2023. Studies included compared patients undergoing abdominal surgery who developed postoperative ileus to those who did not, focusing on costing data. The primary outcome was the total cost of inpatient stay. Risk of bias was assessed using the Newcastle-Ottawa assessment tool. Summary meta-analysis was performed. RESULTS: Of the 2071 studies identified, 88 papers were assessed for full eligibility. The systematic review included nine studies (2005-2022), investigating 1 860 889 patients undergoing general, colorectal, gynaecological and urological surgery. These studies showed significant variations in the definition of postoperative ileus. Six studies were eligible for meta-analysis showing an increase of €8233 (95 per cent c.i. (5176 to 11 290), P < 0.0001, I2 = 95.5 per cent) per patient with postoperative ileus resulting in a 66.3 per cent increase in total hospital costs (95 per cent c.i. (34.8 to 97.9), P < 0.0001, I2 = 98.4 per cent). However, there was significant bias between studies. Five colorectal-surgery-specific studies showed an increase of €7242 (95 per cent c.i. (4502 to 9983), P < 0.0001, I2 = 86.0 per cent) per patient with postoperative ileus resulting in a 57.3 per cent increase in total hospital costs (95 per cent c.i. (36.3 to 78.3), P < 0.0001, I2 = 85.7 per cent). CONCLUSION: The global financial burden of postoperative ileus following abdominal surgery is significant. While further multicentre data using a uniform postoperative ileus definition would be useful, reducing the incidence and impact of postoperative ileus are a priority to mitigate healthcare-related costs, and improve patient outcomes.

Can sarcopenia predict complete response after total neoadjuvant therapy in advanced rectal cancer? A multicentre observational cohort study.

BACKGROUND: The association between sarcopenia and response to neoadjuvant treatment remains unclear. This study investigates sarcopenia as a predictor of overall complete response (oCR) after Total Neoadjuvant Therapy (TNT) for advanced rectal cancer. METHOD: A prospective observational study was performed of patients with rectal cancer undergoing TNT at three South Australian hospitals between 2019 and 2022. Sarcopenia was diagnosed by pretreatment computed tomography measurement of psoas muscle cross-sectional area at the third lumbar vertebra level, normalised for patient height. The primary endpoint was oCR rate defined as the proportion of patients who achieved either clinical complete response (cCR) or pathological complete response. RESULTS: This study included 118 rectal cancer patients with an average age of 59.5 years, 83 (70.3%) of whom formed the non-sarcopenic group (NSG) and 35 (29.7%) the sarcopenic group (SG). The oCR rate was significantly higher in NSG compared with the SG (p < 0.001). cCR rate was significantly greater in NSG compared with the SG (p = 0.001). Multivariate analysis revealed sarcopenia (p = 0.029) and hypoalbuminemia (p = 0.040) were risk factors for cCR and sarcopenia was an independent risk factor for oCR (p = 0.020). CONCLUSION: Sarcopenia and hypoalbuminemia were negatively associated with tumour response following TNT in advanced rectal cancer patients.

A prospective study of diagnostic accuracy of multidisciplinary team and radiology reporting of preoperative colorectal cancer local staging.

INTRODUCTION: The aim of this study was to correlate and assess diagnostic accuracy of preoperative staging at multidisciplinary team meeting (MDT) against the original radiology reports and pathological staging in colorectal cancer patients. METHODS: A prospective observational study was conducted at two institutions. Patients with histologically proven colorectal cancer and available preoperative imaging were included. Preoperative tumor and nodal staging (cT and cN) as determined by the MDT and the radiology report (computed tomography [CT] and/or magnetic resonance imaging [MRI]) were recorded. Kappa statistics were used to assess agreement between MDT and the radiology report for cN staging in colon cancer, cT and cN in rectal cancer, and tumor regression grade (TRG) in patients with rectal cancer who received neoadjuvant therapy. Pathological report after surgery served as the reference standard for local staging, and AUROC curves were constructed to compare diagnostic accuracy of the MDT and radiology report. RESULTS: A total of 481 patients were included. Agreement between MDT and radiology report for cN stage was good in colon cancer (k = .756, Confidence Interval (CI) 95% .686-.826). Agreement for cT and cN and in rectal cancer was very good (kw = .825, CI 95% .758-.892) and good (kw = .792, CI 95% .709-.875), respectively. In the rectal cancer group that received neoadjuvant therapy, agreement on TRG was very good (kw = .919, CI 95% .846-.993). AUROC curves using pathological staging indicated no difference in diagnostic accuracy between MDT and radiology reports for either colon or rectal cancer. CONCLUSION: Preoperative colorectal cancer local staging was consistent between specialist MDT review and original radiology reports, with no significant differences in diagnostic accuracy identified.

Does Sarcopenia Predict Local Response Rates After Chemoradiotherapy for Locally Advanced Rectal Cancer?

BACKGROUND: The predictive value of sarcopenia for tumor response to neoadjuvant chemoradiotherapy is unclear. OBJECTIVE: This study aimed to investigate the association between sarcopenia and pathological tumor regression grade after neoadjuvant chemoradiotherapy in patients with locally advanced rectal cancer. DESIGN: Retrospective cohort study from a prospectively collected database. Univariate logistic regression was performed to assess the association between sarcopenia and tumor response. SETTINGS: This study was conducted at 2 tertiary care centers. PATIENTS: Participants were patients undergoing neoadjuvant chemoradiotherapy for locally advanced rectal cancer (T3/4, N0/+) between 2007 and 2018. INTERVENTION: Sarcopenia was diagnosed using sex-specific cutoffs of lean muscle mass. Using the initial staging CT, lean muscle mass was estimated using the cross-sectional area of the psoas muscle at the level of the third lumbar vertebra, normalized for patient height. MAIN OUTCOME MEASURES: The primary end point was pathological tumor regression grade, defined as good (tumor regression grade 0/1) vs poor (tumor regression grade 2/3). RESULTS: The study included 167 patients with locally advanced rectal cancer with a median age of 60 (20-91) years, with 132 in the nonsarcopenia group and 35 in the sarcopenia group. Eighty-nine percent of patients had stage 3 cancer. Nine patients (5.4%) had a complete clinical response, 1 patient did not respond to treatment and opted for nonoperative management, and the remaining 157 patients (94.0%) proceeded to surgery. Pathological data revealed no significant difference between good tumor regression grade patients in the sarcopenia group compared with the nonsarcopenia group. Univariate analysis revealed BMI ≥25 kg/m 2 to be a risk factor for good tumor regression grade ( p = 0.002). LIMITATIONS: This study was limited by its retrospective design and small sample size. CONCLUSIONS: Sarcopenia is not a predictor of poor neoadjuvant chemoradiotherapy response in patients with locally advanced rectal cancer. Increasing BMI was associated with good tumor regression grade. Future multicentered studies are warranted to validate this finding. See Video Abstract at http://links.lww.com/DCR/C78 . LA SARCOPENIA PREDICE LAS TASAS DE RESPUESTA LOCAL DESPUS DE LA QUIMIORRADIOTERAPIA PARA EL CNCER DE RECTO LOCALMENTE AVANZADO: ANTECEDENTES:El valor predictivo de la sarcopenia para la respuesta tumoral a la quimiorradioterapia neoadyuvante no está claro.OBJETIVO:Este estudio investiga la asociación entre la sarcopenia y el grado de regresión tumoral patológica después de la quimiorradioterapia neoadyuvante en pacientes con cáncer de recto localmente avanzado.DISEÑO:Estudio de cohorte retrospectivo a partir de una base de datos recolectada prospectivamente. Se realizó una regresión logística univariante para evaluar la asociación entre la sarcopenia y la respuesta tumoral.ENTORNO CLINICO:Este estudio se realizó en dos centros de atención terciaria.PACIENTES:Pacientes sometidos a quimiorradioterapia neoadyuvante por cáncer de recto localmente avanzado (T3/4, N0/+) entre 2007-2018.INTERVENCIÓNES:La sarcopenia se diagnosticó utilizando puntos de corte de masa muscular magra específicos por género. Utilizando la tomografía computarizada de estadificación inicial, se estimó la masa muscular magra utilizando el área transversal del músculo psoas a nivel de la tercera vértebra lumbar, normalizada para la altura del paciente.PRINCIPALES MEDIDAS DE VALORACIÓN:El criterio principal de valoración fue el grado de regresión tumoral patológica, definido como bueno (grado de regresión tumoral 0/1) frente a malo (grado de regresión tumoral 2/3).RESULTADOS:El estudio incluyó a 167 pacientes con cáncer de recto localmente avanzado con una mediana de edad de 60 años (20-91), 132 en el grupo sin sarcopenia y 35 en el grupo con sarcopenia. Ochenta y nueve por ciento estaban en etapa III. Seis pacientes (5,4%) tuvieron respuesta clínica completa sostenida, un paciente no respondió al tratamiento y optó por manejo conservador, los 157 restantes (94,0%) procedieron a cirugía. Los datos patológicos no revelaron diferencias significativas entre los pacientes con buen grado de regresión tumoral en el grupo de sarcopenia en comparación con el grupo sin sarcopenia. El análisis univariado reveló que un IMC ≥25 kg/m2 era un factor de riesgo para un buen grado de regresión tumoral (p = 0,002).LIMITACIONES:Este estudio estuvo limitado por su diseño retrospectivo y tamaño de muestra pequeño.CONCLUSIÓNES:La sarcopenia no es un predictor de mala respuesta a la quimiorradioterapia neoadyuvante en pacientes con cáncer de recto localmente avanzado. El aumento del IMC se asoció con un buen grado de regresión tumoral. Se justifican futuros estudios multicéntricos para validar este hallazgo. Consulte Video Resumen en http://links.lww.com/DCR/C78 . (Traducción-Dr. Ingrid Melo ).

Personalized total neoadjuvant therapy versus chemotherapy during the 'wait period' versus standard chemoradiotherapy for locally advanced rectal cancer.

BACKGROUND: This study aimed to compare current treatment response rates with personalized Total Neoadjuvant Therapy (pTNT), against extended chemotherapy in the 'wait period' (xCRT) and standard chemoradiotherapy (sCRT) with adjuvant chemotherapy for rectal cancer. METHODS: This was a multicentre retrospective cohort analysis. Consecutive patients with rectal cancer treated with pTNT over a 3.9-year period were compared to a historical cohort of patients treated with xCRT or sCRT as part of the published WAIT Trial. pTNT patients received 8 cycles mFOLFOX6 or 6 cycles CAPOX in the neoadjuvant setting (no adjuvant treatment). Patients in the WAIT Trial received either 3 cycles 5-FU/LV during the 10-week wait period after chemoradiotherapy or standard chemoradiotherapy, followed by adjuvant chemotherapy. The primary endpoint was overall complete response (oCR) rate defined as the proportion of patients who achieved either complete clinical response (cCR) or pathological complete response (pCR). RESULTS: Of 284 patients diagnosed with rectal cancer during the 3.9-year period, 107 received pTNT. Forty of these were matched with 49 patients from the WAIT Trial (25 received xCRT and 24 received sCRT). There was a significant difference in oCR between the groups (pTNT n = 21, xCRT n = 6, sCRT n = 7, P = 0.043). Of the patients that underwent surgery, pCR occurred in 13 patients with no significant difference between groups (P = 0.415). There were no significant differences in 2-year disease-free survival or overall survival. CONCLUSION: Compared with sCRT and xCRT, pTNT results in a significantly higher complete response rate which may facilitate organ preservation.

Clinical and biochemical predictors of tumor response after neoadjuvant therapy in rectal cancer.

BACKGROUND: Patients who have a good clinical and/or pathologic response to neoadjuvant chemoradiotherapy (nCRT) for rectal cancer have better long-term outcomes and can potentially be spared morbid surgery. This study aimed to identify pretreatment clinical and biochemical predictors of response to neoadjuvant treatment for rectal cancer. METHODS: Patients undergoing neoadjuvant therapy for rectal cancer between 2007 and 2022 were retrospectively included. Those patients who achieved a complete clinical response were offered a nonoperative management strategy and the remaining patients underwent surgical resection. The primary endpoint was tumor regression grade (TRG) based on radiological imaging (mrTRG) or pathology (pTRG). Patient response was classified as good (mrTRG 1-2 or pTRG 0-1) versus poor (mrTRG 3-4 or pTRG 2-3). Logistic regression was performed to determine predictors of TRG. RESULTS: A total of 984 patients with rectal cancer were identified of which 274 met the inclusion criteria. Of 274 patients, 228 (83%) underwent surgical resection. A good TRG response was observed in 119 (41%) patients, and a complete response was achieved in 53 (17%) patients. On univariable and multivariable logistic regression, clinical T2 stage and body mass index of ≥25 kg/m2 were significant predictors of a good TRG. Clinical T2 stage and a personalised total neoadjuvant therapy regimen were significant predictors of complete response. CONCLUSION: Clinical T2 stage and a BMI≥25 kg/m2 were predictors of good response to neoadjuvant therapy for rectal cancer. Future prospective studies are required to confirm these findings and evaluate their potential use in better targeting of nCRT.

Personalized total neoadjuvant therapy (pTNT) for advanced rectal cancer with tailored treatment sequencing based on clinical stage at presentation.

BACKGROUND: This study aimed to assess short-term outcomes of a personalized total neoadjuvant treatment (pTNT) protocol, with treatment sequencing based on clinical stage at presentation. METHODS: A multidisciplinary pTNT protocol was implemented across two metropolitan hospitals. This consists of two-schema based on clinical stage: patients with distant failure risk were offered induction chemotherapy before chemoradiation (nCRT), and patients with locoregional failure risk received nCRT followed by consolidation chemotherapy. Patients underwent surgical resection unless a complete clinical response (cCR) was achieved, in which case non-operative management (NOM) was offered. A prospective cohort analysis of all patients with rectal cancer who underwent pTNT with curative intent between Jan 2019 and Aug 2022 was performed. RESULTS: Of 270 patients referred with rectal cancer, 102 received pTNT with curative intent and 79 have completed their treatment thus far. Thirty-three patients (41.8%) received induction chemotherapy and 46 (58.2%) received consolidation chemotherapy per protocol. The percentage of patients with EMVI, resectable M1 disease, cT4 disease, and positive lateral lymph nodes were 54.4%, 36.7%, 27.8% and 15.2%, respectively. Overall, 32 (40.5%) patients had cCR and 4 (5.1%) pCR, and 40 (50.6%) patients had non-operative management. Grade 3 toxicity was reported in 10.1% of patients and only three patients (3.8%) experienced Grade 4 chemotherapy-related toxicity, with no treatment related mortality. CONCLUSION: Early results with a defined two-schema pTNT protocol are encouraging and suggest that tailoring sequencing to disease risk at presentation may represent the optimal balance between local and distant disease control, as well as treatment toxicity.

Cost of postoperative ileus following colorectal surgery: A cost analysis in the Australian public hospital setting.

AIM: Postoperative ileus (POI) following surgery results in significant morbidity, drastically increasing hospital costs. As there are no specific Australian data, this study aimed to measure the cost of POI after colorectal surgery in an Australian public hospital. METHODS: A cost analysis was performed, for major elective colorectal surgical cases between 2018 and 2021 at the Royal Adelaide Hospital. POI was defined as not achieving GI-2, the validated composite measure, by postoperative day 4. Demographics, length of stay and 30-day complications were recorded retrospectively. Costings in Australian dollars were collected from comprehensive hospital billing data. Univariate and multivariate analyses were performed. RESULTS: Of the 415 patients included, 34.9% (n = 145) developed POI. POI was more prevalent in males, smokers, previous intra-abdominal surgery, and converted laparoscopic surgery (p < 0.05). POI was associated with increased length of stay (8 vs. 5 days, p < 0.001) and with higher rates of complications such as pneumonia (15.2% vs. 8.1%, p = 0.027). Total cost of inpatient care was 26.4% higher after POI (AU$37,690 vs. AU$29,822, p < 0.001). POI was associated with increased staffing costs, as well as diagnostics, pharmacy, and hospital services. On multivariate analysis POI, elderly patients, stoma formation, large bowel surgery, prolonged theatre time, complications and length of stay were predictive of increased costs (p < 0.05). CONCLUSION: In Australia, POI is significantly associated with increased complications and higher costs due to prolonged hospital stay and increased healthcare resource utilisation. Efforts to reduce POI rates could diminish its morbidity and associated expenses, decreasing the burden on the healthcare system.

Artificial intelligence for body composition and sarcopenia evaluation on computed tomography: A systematic review and meta-analysis.

PURPOSE: Tracing muscle groups manually on CT to calculate body composition parameters and diagnose sarcopenia is costly and time consuming. Artificial Intelligence (AI) provides an opportunity to automate this process. In this systematic review, we aimed to assess the performance of CT-based AI segmentation models used for body composition analysis. METHOD: We systematically searched PubMed (MEDLINE), Embase, Web of Science and Scopus for studies published from January 1, 2011, to May 27, 2021. Studies using AI models for assessment of body composition and sarcopenia on CT scans were included. Excluded were studies that used muscle strength, physical performance data, DXA and MRI. Meta-analysis was conducted on the reported dice similarity coefficient (DSC) and Jaccard similarity coefficient (JSC) of AI models. RESULTS: 284 studies were identified, of which 24 could be included in the systematic review. Among them, 15 were included in the meta-analysis, all of which used deep learning. Deep learning models for skeletal muscle (SM) segmentation performed with a pooled DSC of 0.941 (95 %CI 0.923-0.959) and a pooled JSC of 0.967 (95 %CI 0.949-0.986). Additionally, a pooled DSC of 0.967 (95 %CI 0.958-0.978), 0.963 (95 %CI 0.957-0.969) and 0.970 (95 %CI 0.944-0.996) was observed for segmentation of subcutaneous adipose tissue (SAT), visceral adipose tissue (VAT), and bone, respectively. SM studies suffered from significant publication bias, and heterogeneity among the included studies was considerable. CONCLUSIONS: CT-based deep learning models can facilitate the automated segmentation of body composition and aid in sarcopenia diagnosis. More rigorous guidelines and comparative studies are required to assess the efficacy of AI segmentation models before incorporating these into clinical practice.

Examining the effect of Libet clock stimulus parameters on temporal binding.

Temporal binding refers to the subjective temporal compression between actions and their outcomes. It is widely used as an implicit measure of sense of agency, that is, the experience of controlling our actions and their consequences. One of the most common measures of temporal binding is the paradigm developed by Haggard, Clark and Kalogeras (2002) based on the Libet clock stimulus. Although widely used, it is not clear how sensitive the temporal binding effect is to the parameters of the clock stimulus. Here, we present five experiments examining the effects of clock speed, number of clock markings and length of the clock hand on binding. Our results show that the magnitude of temporal binding increases with faster clock speeds, whereas clock markings and clock hand length do not significantly influence temporal binding. We discuss the implications of these results.

The impact of acetylcholinesterase inhibitors on ileus and gut motility following abdominal surgery: a clinical review.

Postoperative ileus is a common complication in the days following colorectal surgery occurring in up to 50% of patients. When prolonged, this complication results in significant morbidity and mortality, doubling the total costs of hospital stay. Postoperative ileus (POI) results from the prolonged inflammatory phase that is mediated in part by the cholinergic anti-inflammatory pathway. Acetylcholinesterase inhibitors, such as neostigmine and pyridostigmine, delay the degradation of acetylcholine at the synaptic cleft. This increase in acetylcholine has been shown to increase gut motility. They have been effective in the treatment of acute colonic pseudo-obstruction, but there is limited evidence for the use of these medications for reducing the incidence of POI. This review was conducted to summarise the evidence of acetylcholinesterase inhibitors' effect on gut motility and discuss their potential use as part of an enhanced recovery protocols to prevent or treat POI.

Artificial intelligence for pre-operative lymph node staging in colorectal cancer: a systematic review and meta-analysis.

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 .