Background: Colorectal cancer is one of the most common cancers worldwide and has a high mortality rate following disease recurrence. Treatment efficacy is maximized by providing tailored cancer treatment, ideally involving surgical resection and personalized neoadjuvant and adjuvant therapies, including chemotherapy, radiotherapy and increasingly, targeted therapy. Early detection of recurrence or disease progression results in more treatable disease and is essential to improving survival outcomes. Recent advances in the understanding of tumor genetics have resulted in the discovery of circulating tumor DNA (ctDNA). A growing body of evidence supports the use of these sensitive biomarkers in detecting residual disease and diagnosing recurrence as well as enabling targeted and tumor-specific adjuvant therapies. Methods: A literature search in Pubmed was performed to identify all original articles preceding April 2019 that utilize ctDNA for the purpose of monitoring response to colorectal cancer treatment. Results: Ninety-two clinical studies were included. These studies demonstrate that ctDNA is a reliable measure of tumor burden. Studies show the utility of ctDNA in assessing the adequacy of surgical tumor clearance and changes in ctDNA levels reflect response to systemic treatments. ctDNA can be used in the selection of targeted treatments. The reappearance or increase in ctDNA, as well as the emergence of new mutations, correlates with disease recurrence, progression, and resistance to therapy, with ctDNA measurement allowing more sensitive monitoring than currently used clinical tools. Conclusions: ctDNA shows enormous promise as a sensitive biomarker for monitoring response to many treatment modalities and for targeting therapy. Thus, it is emerging as a new way for guiding treatment decisions—initiating, altering, and ceasing treatments, or prompting investigation into the potential for residual disease. However, many potentially useful ctDNA markers are available and more work is needed to determine which are best suited for specific purposes and for improving specific outcomes.

Lactate Pro devices have a significant difference, but when used in clinical practice on cord blood after delivery, this is unlikely to be meaningful. In intrapartum fetal surveillance, a systematic overestimation might lead to unnecessary intervention. It is possible to retrospectively predict the likely level of lactate at birth in delayed cord samples.

Background: While most colorectal cancer (CRC) recurrences reportedly occur within 3 years following curative treatment, many studies are limited by short-term follow-up. This study examines the time to recurrence of CRC in a large Australian cohort with a long follow-up period and assesses whether time to recurrence has changed over time.Methods: A comprehensive prospective database of patients undergoing resection for CRC is maintained at Concord Hospital, Sydney. Demographic and time to recurrence data were extracted for patients who developed a recurrence following potentially curative resection for colon cancer from 1995 to 2010 and rectal cancer from 1971 to 2010. Non-deceased patients had a minimum of 5 years follow-up. Results: Between 1995 and 2010, 2575 patients with CRC underwent surgery. After exclusions, 386 had recurrence following potentially curative resection, ranging from 1 to 172.5 months (median 20.3) after treatment. Within 1 year, 27.5% recurred, 57.5% by 2 years, 74.6% by 3 years, 85.5% by 4 years and 89.6% by 5 years. There was no difference in time to recurrence between colon and rectal cancers (P = 0.674). Among patients having a potentially curative resection for rectal cancer between 1971 and 2010, 386 recurred. There was no difference in time to recurrence by decade (P = 0.863). Conclusion: The majority of recurrences occurred within 3 years of curative treatment. Had surveillance been limited to 5 years, detection of more than 10% of recurrences would have been delayed. Time to recurrence for rectal cancer has not changed in over 40 years, despite treatment advances.

Backgrounds: Surgery remains mainstay management for colon cancer. Post-operative anastomotic leak (AL) carries significant morbidity and mortality. Rates of, and risk factors associated with AL following right hemicolectomy remain poorly documented across Australia and New Zealand. This study examines the Bowel Cancer Outcomes Registry (BCOR) to address this. Methods: A retrospective cohort study was undertaken of consecutive BCOR-registered right hemicolectomy patients undergoing resection for colon cancer (2007)(2008)(2009)(2010)(2011)(2012)(2013)(2014)(2015)(2016)(2017)(2018)(2019)(2020)(2021). The primary outcome measure was AL incidence. Clinicopathological data were extracted from the BCOR. Factors associated with AL and primary anastomosis were identified using logistic regression. AL-rate trends were assessed by linear regression. Results: Of 13 512 patients who had a right hemicolectomy (45.2% male, mean age 72.5 years, SD 12.1), 258 (2.0%) had an AL. On multivariate analysis, male sex (OR 1.33; 95% CI 1.03-1.71) and emergency surgery (OR 1.41; 95% CI 1.04-1.92) were associated with AL. Private health insurance status (OR 0.66; 95% CI 0.50-0.88) and minimallyinvasive surgery (OR 0.61; 95% CI 0.47-0.79) were protective for AL. Anastomotic technique (handsewn versus stapled) was not associated with AL (P = 0.84). Patients with higher ASA status (OR 0.47; 95% CI 0.39-0.58), advanced tumour stage (OR 0.56; 95% CI 0.50-0.63), and emergency surgery (OR 0.16; 95% CI 0.13-0.20) were less likely to have a primary anastomosis. AL-rate and year of surgery showed no association (P = 0.521). Conclusion:The AL rate in Australia and New Zealand following right hemicolectomy is consistent with the published literature and was stable throughout the study period. Sex, emergency surgery, insurance status, and minimally invasive surgery are associated with AL incidence.

Recurrent neo-left colonic volvulus is a rare complication following anterior resection. The conventional approach to treating recurrent volvulus is a large bowel resection with anastomosis or colostomy formation after successful endoscopic decompression. However, in elderly and comorbid patients, this can result in significant morbidity or mortality. Laparoscopic colopexy is a less invasive alternative that has not been previously reported for the treatment of neo-left colonic volvulus. We describe a case of an 86-year-old male who presented with recurrent neo-left colonic volvulus 10 years post-laparoscopic anterior resection for cancer. A laparoscopic colopexy was performed to resolve the volvulus and prevent future recurrence. Interrupted prolene sutures were used to fix the neo-left colon to the posterior stomach and the left lateral abdominal wall. The patient had an uncomplicated postoperative recovery and was discharged 6 days after surgery. He was well at 6 months follow-up.

Objective: Fetal scalp lactate has largely replaced pH analysis to assess intrapartum hypoxia. Many obstetrics units use hand-held lactate meters to measure umbilical blood because of its affordability and ease of use. We sought to investigate the agreement of Lactate Pro TM with a reference method blood gas analyser and to determine its usefulness with a recommended cutoff value of 4.8 mmol/L. Methods: Prospective study carried out at a tertiary institution where 237 arterial and 233 venous samples from umbilical cords of 16 elective caesarean and 285 emergency deliveries were measured using Lactate Pro TM and ABL735 Sesries Acid-Base analyser. Limits of agreement were analysed using Bland-Altman plots. Results: Lactate Pro TM differentiated fewer deliveries as "high risk" (≥4.8 mmol/L) and more as "low risk" (<2.2 mmol/L). Limits of agreement for lactate values (as measured by Lactate Pro TM) were-1.46-0.97 mmol/L for arterial lactate levels <4.8 mmol/L and-3.21-0.88 mmol/L for arterial lactate levels ≥ 4.8 mmol/L. Conclusion: There was a poorer agreement between the two devices at higher lactate values. Lactate Pro TM underestimates by up to 3.2 mmol/L; a 4.8 mmol/L reading may actually signify a lactate level of 8.0 mmol/L, indicating severe metabolic acidosis. We caution the use of this device in assessing fetal lactate levels.

Background: Radiological angioembolization is an important strategy in management of acute colonic bleeding. Due to requirement for specialized interventional radiology, many hospitals rely on transfer for this service. This study aimed to identify patient and clinical factors associated with positive (blush) computed tomography mesenteric angiogram (CTMA) or need for invasive angiography. The secondary aim was to identify a patient population who may forego transfer and be safely managed in a regional centre. Methods: All presentations to Central Coast Local Health District with colonic bleeding from