Intraoperative Fractions of Inspiratory Oxygen Are Associated With Recurrence-Free Survival After Elective Cancer Surgery

Background: Choice of the fraction of inspiratory oxygen (FiO2) is controversial. The objective of this analysis was to evaluate whether intraoperative FiO2 was associated with recurrence-free survival after elective cancer surgery.Methods and Analysis: In this single-center, retrospective study, we analyzed 1,084 patients undergoing elective resection of pancreatic (n = 652), colorectal (n = 405), or hepatic cancer (n = 27) at Heidelberg University Hospital between 2009 and 2016. Intraoperative mean FiO2 values were calculated. For unstratified analyses, the study cohort was equally divided into a low- and a high-FiO2 group. For cancer-stratified analyses, this division was done within cancer-strata. The primary outcome measure was recurrence-free survival until the last known follow-up. Groups were compared using Kaplan–Meier analysis. A stratified log rank test was used to control for different FiO2 levels and survival times between the cancer strata. Cox-regression analyses were used to control for covariates. Sepsis, reoperations, surgical-site infections, and cardiovascular events during hospital stay and overall survival were secondary outcomes.Results: Median FiO2 was 40.9% (Q1–Q3, 38.3–42.9) in the low vs. 50.4% (Q1–Q3, 47.4–54.7) in the high-FiO2 group. Median follow-up was 3.28 (Q1–Q3, 1.68–4.97) years. Recurrence-free survival was considerable higher in the high-FiO2 group (p < 0.001). This effect was also confirmed when stratified for the different tumor entities (p = 0.007). In colorectal cancer surgery, increased FiO2 was independently associated with increased recurrence-free survival. The hazard for the primary outcome decreased by 3.5% with every 1% increase in FiO2. The effect was not seen in pancreatic cancer surgery and we did not find differences in any of the secondary endpoints.Conclusions: Until definite evidence from large-scale trials is available and in the absence of relevant clinical conditions warranting specific FiO2 values, perioperative care givers should aim for an intraoperative FiO2 of 50% in abdominal cancer surgery as this might benefit oncological outcomes.

EP.TU.637To Resect or Not to Resect? Incidental Meckel’s Diverticulum at Colon Cancer Resection

Case An 85-year-old man underwent elective resection for a large proximal transverse colon tumour. At the time of this open extended right hemicolectomy, a Meckel’s diverticulum was identified in the ileum, but not resected considering the age and character of the diverticulum. However, on the sixth post-operative day, he developed small bowel obstructive symptoms which required a reoperation. It was found that the cause of obstruction was identified as a long pedunculated Meckel’s diverticulum wrapped 15 centimetres proximal to the anastomosis. Considering the general condition of the patient and co-morbidities, resection of the Meckel’s diverticulum and loop ileostomy was performed. The patient has now recovered and is being followed up in the community awaiting stoma reversal. Background Occurring in 2% of the population, Meckel’s diverticulum is the most common congenital gastrointestinal malformation. Complications of a Meckel’s diverticulum include obstruction, haemorrhage, perforation, diverticulitis and intussusception. Most complications manifest in childhood and are less likely to occur in adults. The indication for resection of incidental Meckel’s diverticula in an adults is still debated amongst surgeons. Discussion and Conclusion This case demonstrates an unfortunate scenario of a post-operative complication from an abnormality detected at the time of the index surgery. A recent systematic review has shown that evidence in literature remains controversial for resection in asymptomatic Meckel’s Diverticulum. There are even scoring systems to facilitate decisions in such situations. This case offers an interesting perspective where morbidity may have been reduced if resection was undertaken.

SP10.1.9 Delay to Elective Colorectal Cancer Surgery and its Potential Implications: A Systematic Review and Meta-analysis

Aim The ongoing Covid-19 pandemic has interrupted surgical treatment of colorectal cancer (CRC). This systematic review will assess literature concerning the risk of delay of elective surgery for CRC patients, focusing on overall survival (OS) and disease-free survival (DFS). Methods A systematic review was performed as per PRISMA guidelines (PROSPERO ID: CRD42020189158). Medline, EMBASE and Scopus were searched. Patients over 18 with a diagnosis of colon or rectal cancer who received elective surgery as primary treatment were included. Delay was defined as the period between CRC diagnosis and day of surgery. Metanalyses of the outcomes OS and DFS were conducted. Forest plots, funnel plots, tests of heterogeneity, and estimated Number Needed to Harm (NNHs) were produced. Results Of 3753 articles identified, seven met the inclusion criteria. Encompassing 314560 patients, three of the seven studies showed a delay to elective resection was associated with poorer OS or DFS. OS was assessed at a one-month delay, the HR for six datasets was 1.13 (95%CI 1.02-1.26, p = 0.020) and at three months the HR for three datasets was 1.57 (95%CI 1.16-2.12, p = 0.004). Estimated NNHs for a delay at one month and three months were 35 and 10 respectively. Delay was non-significantly negatively associated with DFS on metanalysis. Conclusions This review recommends elective surgery for CRC patients is not postponed longer than four weeks, as evidence suggests extended delays from diagnosis are associated with poorer outcomes. Focused research is essential so patient groups can be prioritized based on risk-factors for future pandemics.

732 Delay to Elective Colorectal Cancer Surgery and its Potential Implications During the Covid-19 Pandemic: A Systematic Review and Metanalysis

Aim The ongoing Covid-19 pandemic has interrupted the surgical treatment of colorectal cancer (CRC). This systematic review will assess literature concerning the risk of delay of elective surgery for CRC patients, focusing on overall survival (OS) and disease-free survival (DFS). Method A systematic review was performed as per PRISMA guidelines (PROSPERO ID: CRD42020189158). Medline, EMBASE and Scopus were searched. Delay to elective surgery was defined as the period between CRC diagnosis and the day of surgery. Metanalyses of the outcome’s OS and DFS were conducted. Forest plots, funnel plots, and tests of heterogeneity were produced. An estimated Number Needed to Harm (NNH) was calculated for statistically significant pooled Hazard Ratios (HRs). Results Of 3753 articles identified, seven met the inclusion criteria. Encompassing 314560 patients, three of the seven studies showed that a delay to elective resection is associated with poorer OS or DFS. OS was assessed at a one-month delay, the HR for six datasets was 1.13 (95%CI 1.02-1.26, p = 0.020) and at three months the pooled HR for three datasets was 1.57 (95%CI 1.16-2.12, p = 0.004). Estimated NNHs for a delay at one month and three months were 35 and 10 respectively. Delay was non-significantly negatively associated with DFS on meta-analysis. Conclusions This review recommends that elective surgery for CRC patients is not postponed, as evidence suggests delays from diagnosis are associated with poorer outcomes. Focused research is essential so that patient groups can be prioritized based on risk factors for future pandemics.

O22 Risk of death following pulmonary complications of surgery with and without SARS-CoV-2 infection: a comparative analysis of pre-pandemic and pandemic cohort studies

Introduction No comparison has been made between the risk of death following pulmonary complications in patients with and without SARS-CoV-2 infection. This study aimed to determine the incidence and impact of pulmonary complications before and during the SARS-CoV-2 pandemic. Method A patient-level comparative analysis of two international prospective cohort studies; conducted pre-pandemic (22 January to 19 October 2019) and during the SARS-CoV-2 pandemic (local emergence of COVID-19 up to 19 April 2020). Patients undergoing elective resection of an intra-abdominal cancer with curative intent across five surgical oncology disciplines were included in analysis. The primary outcome measure was the mortality within 30 days of surgery. Result This study included 7402 patients from 50 countries; 3031 (40.9%) were operated pre-pandemic and 4371 (59.1%) during the pandemic. 5.1% (n = 224/4371) of patients during the pandemic developed a postoperative SARS-CoV-2 infection. Despite selection of lower risk cases during the pandemic, the rates of pulmonary complications pre were similar (6.3% vs 6.9%, P = 0.280). However, the risk of death after surgery was higher during the pandemic (2.0% vs 0.7%, P < 0.001). The population attributable fraction of deaths due to pulmonary complications was 37.7% (95% CI: 15.2–64.7%) pre-pandemic and 66.0% (95% CI: 48.6–79.3%) during the pandemic. The increased mortality was largely attributable to SARS-CoV-2 infection; 68.9% (n = 31/45) of deaths patients with pulmonary complications occurred following SARS-CoV-2 infection. Conclusion Pulmonary complications are the primary driver of death after elective surgery during the pandemic. Care providers must urgently reconfigure surgical services to protect patients from perioperative SARS-CoV-2 infection. Take-home Message Pulmonary complications are the primary driver of death after elective surgery during the pandemic. Care providers must urgently reconfigure surgical services to protect patients from perioperative SARS-CoV-2 infection.

A prospective study of outcome of resection anastomosis in elective GI surgeries.

Background: Bowel anastomosis is successful when there is accurate union with no tension.Previous literature has compared between hand suturing and stapling devices in retrospective andprospective designs with varying outcomes. In this study a comparison between hand suturing andsurgical stapling in patients undergoing bowel surgery is done. Methods: A prospective study designover a period of 12 months was conducted in 40 patients undergoing elective resection andanastomosis. Different time parameters for anastomisis procedure, time taken for bowel sounds toreturn, resumption of oral feeds, postoperative hospital stay were collected. Follow up for 30 dayspost-operative was done. Results: In total forty patients were studied out of which twenty patientsunderwent hand sewn and twenty patients underwent stapler anastomosis. Main group analysis inmean time durations between hand sewn and stapler anastomosis were respectively; 35.25 minutesand 12 minutes for anastomosis, 3.4 days and 3.35 days for return of bowel sounds, 4.08 days and4 days for resumotion of oral feeds, 9.35 days and 8.50 days for post-operative hospital stay. A sub-group analysis was also done.Conclusion: Stapler anastomosis had shorter anastomosis time andtotal duration of operation compared to hand sewn anastomosis. However no difference was seen inreturn of bowel activity, resumption of oral feeds and duration of hospital stay.

V9 Risk of death following pulmonary complications after surgery with and without SARS-CoV-2 infection: a pooled analysis of individual patient data from pre-pandemic and pandemic international cohort studies

Introduction Whilst the severe consequences of COVID-19 around the time of surgery are well described, no comparison has been made to pulmonary complications in the absence of infection. This study aimed to compare postoperative death in patients with and without SARS-CoV-2 infection. Methods A patient-level comparative analysis of two international prospective cohort studies; one conducted before (January to October 2019) and one during the SARS-CoV-2 pandemic (from local emergence of COVID-19 to April 2020). Patients undergoing elective resection of an intra-abdominal cancer with curative intent were included in a multilevel logistic regression. The primary outcome was 30-day postoperative mortality. Results Of 7402 patients included, 3031 underwent surgery before and 4371 during the pandemic. Overall, 6.5% (n = 484) patients suffered a pulmonary complication, 5.1% had a SARS-CoV-2 infection diagnosed, and 1.4% patients (n = 107) died. Compared to patients without pulmonary complications, those with SARS-CoV-2 pulmonary complications had a higher adjusted odds of death (OR: 54.14, 95%CI: 23.46 to 124.91, p < 0.001) than those with non-SARS-CoV-2 pulmonary complications (OR: 7.20, 95%CI: 3.85 to 13.45, p < 0.001). Conclusion Postoperative pulmonary complications were associated with increased 30-day mortality. SARS-CoV-2 associated pulmonary complications were associated with a far higher mortality than a non-SAR-CoV-2 pulmonary complication.