The role of preoperative iron deficiency in colorectal cancer patients: prevalence and treatment

Preoperative iron infusion does not reduce the requirement for blood transfusion in colorectal cancer surgery

BACKGROUND

Allogeneic blood transfusions (BT) for patients undergoing colorectal cancer surgery have demonstrated to increase postoperative morbidity and mortality. It has been suggested that the utilization of preoperative iron infusions may reduce the requirement for allogeneic BT in these patients. The aim of this project is to ascertain whether the preoperative use of intravenous iron is significantly associated with a reduction in perioperative blood transfusion requirement.

METHODS

A retrospective study of 130 patients was conducted in Blacktown Hospital, Australia. Data pertaining to patient demographics, as well as quantity of preoperative iron infusion and perioperative blood transfusion was collected.

RESULTS

Twenty-six (20%) patients required perioperative BT. Twenty-seven underwent preoperative iron infusion, with 20 of them not requiring BT and seven requiring BT. There was no evidence to suggest preoperative iron infusion reduces blood transfusion requirement (RR 1.55, 95% CI 0.57-4.18, P=0.39). For elective procedures, no significance was also demonstrated (RR 1.20, 95% CI 0.29-4.92, P=0.80).

CONCLUSIONS

There is no evidence suggesting that preoperative iron infusion reduces the requirement for perioperative blood transfusion in colorectal cancer surgery.

Iron metabolism in colorectal cancer: a balancing act

BACKGROUND

Colorectal cancer (CRC) is the third most commonly diagnosed cancer and the second deadliest malignancy worldwide. Current dietary habits are associated with increased levels of iron and heme, both of which increase the risk of developing CRC. The harmful effects of iron overload are related to the induction of iron-mediated pro-tumorigenic pathways, including carcinogenesis and hyperproliferation. On the other hand, iron deficiency may also promote CRC development and progression by contributing to genome instability, therapy resistance, and diminished immune responses. In addition to the relevance of systemic iron levels, iron-regulatory mechanisms in the tumor microenvironment are also believed to play a significant role in CRC and to influence disease outcome. Furthermore, CRC cells are more prone to escape iron-dependent cell death (ferroptosis) than non-malignant cells due to the constitutive activation of antioxidant genes expression. There is wide evidence that inhibition of ferroptosis may contribute to the resistance of CRC to established chemotherapeutic regimens. As such, ferroptosis inducers represent promising therapeutic drugs for CRC.

CONCLUSIONS AND PERSPECTIVES

This review addresses the complex role of iron in CRC, particularly in what concerns the consequences of iron excess or deprivation in tumor development and progression. We also dissect the regulation of cellular iron metabolism in the CRC microenvironment and emphasize the role of hypoxia and of oxidative stress (e.g. ferroptosis) in CRC. Finally, we underline some iron-related players as potential therapeutic targets against CRC malignancy.

Impact of low serum iron on treatment outcome of PD-1 inhibitors in advanced gastric cancer

BACKGROUND

The aim of this study was to investigate the influence of serum iron levels in advanced gastric cancer (GC) patients treated with programmed cell death protein-1 (PD-1) inhibitors.

METHODS

We retrospectively reviewed 149 GC patients who were treated with PD-1 inhibitors at our center. Clinicopathological characteristics, laboratory data, and clinical outcomes were analyzed.

RESULTS

Multivariate analysis showed that Eastern Cooperative Oncology Group performance status (ECOG PS), histological subtype, and baseline serum iron levels were independent prognostic factors for overall survival (OS), while ECOG PS, multiple metastatic sites, and baseline serum iron levels were independent prognostic factors for progression-free survival (PFS). Patients with baseline low serum iron levels (LSI) had a significantly shorter median OS and PFS compared to patients with normal serum iron levels (NSI) (Median OS: 7 vs. 14 months, p = 0.001; median PFS: 3 vs. 5 months, p = 0.005). Patients with baseline LSI had a disease control rate (DCR) of 58.3% at 2 months after PD-1 inhibitor initiation (M2), compared to 81.1% in patients with NSI (p = 0.005). Patients with baseline LSI had a DCR of 43.8% at 4 months, compared to 64.2% in patients with NSI (p = 0.017).

CONCLUSIONS

LSI was associated with worse OS, PFS, and DCR in GC patients treated with PD-1 inhibitors and might be a quick and efficient biomarker to predict the efficacy of PD-1 inhibitors.

Iron Surveillance and Management in Gastro-Intestinal Oncology Patients: A National Physician Survey

PURPOSE

Iron deficiency (ID) is a complication of gastrointestinal (GI) cancers that may manifest as iron deficiency anemia (IDA). Serum ferritin monitoring and oral iron supplementation have the limitations of being falsely elevated and poorly absorbed, respectively. This study aims to assess the discordance in surveillance, treatment practices, and awareness of ID/IDA in GI cancer patients by Canadian physicians treating these patients.

METHODS

From February 2020 to September 2021, a 22-question electronic survey was sent to medical oncologists (MOs), surgical oncologists (SOs), and gastroenterologists (GEs). The survey collected information about four domains: physician demographics, surveillance practices, treatment practices, and awareness of ID/IDA in GI cancer patients and ASCO/ASH guidelines.

RESULTS

A total of 108 (34 MOs, 19 SOs, and 55 GEs) of the 872 (12.4%) invited physicians completed the survey. Of these, 26.5% of MOs, 36.8% of SOs, and 70.9% of GEs measured baseline iron parameters, with few continuing surveillance throughout treatment. Ferritin was widely measured by MOs (88.9%), SOs (100%), and GEs (91.4%). Iron was supplemented if ID/IDA was identified pre-treatment by 66.7% of MOs, 85.7% of SOs, and 94.2% of GEs. Parenteral iron was prescribed by SOs (100%), while oral iron was prescribed by MOs (83.3%) and GEs (87.9%). Only 18.6% of physicians were aware of the ASCO/ASH guidelines regarding erythropoiesis-stimulating agents with parenteral iron for treating chemotherapy-induced anemia.

CONCLUSION

Results illustrate variations in practice patterns for IDA management across the different physician specialties. Moreover, there appeared to be gaps in the knowledge and care surrounding evidence-based IDA management principles which may contribute to poor clinical outcomes.

Perioperative Iron Deficiency in Patients Scheduled for Major Elective Surgeries: A French Prospective Multicenter Cross-Sectional Study

BACKGROUND

The management of perioperative iron deficiency is a component of the concept of patient blood management. The objective of this study was to update French data on the prevalence of iron deficiency in patients scheduled for major surgery.

METHODS

The CARENFER PBM study was a prospective cross-sectional study in 46 centers specialized in orthopedic, cardiac, urologic/abdominal, or gynecological surgery. The primary end point was the prevalence of iron deficiency at the time of surgery (D-1/D0) defined as serum ferritin <100 µg/L and/or transferrin saturation (TSAT) <20%.

RESULTS

A total of 1494 patients (mean age, 65.7 years; women, 49.3%) were included from July 20, 2021 to January 3, 2022. The prevalence of iron deficiency in the 1494 patients at D-1/D0 was 47.0% (95% confidence interval [CI], 44.5-49.5). At 30 days after surgery, the prevalence of iron deficiency was 45.0% (95% CI, 42.0-48.0) in the 1085 patients with available data. The percentage of patients with anemia and/or iron deficiency increased from 53.6% at D-1/D0 to 71.3% at D30 ( P < .0001), mainly due to the increase of patients with both anemia and iron deficiency (from 12.2% at D-1/D0 to 32.4% at D30; P < .0001). However, a treatment of anemia and/or iron deficiency was administered preoperatively to only 7.7% of patients and postoperatively to 21.7% (intravenous iron, 14.2%).

CONCLUSIONS

Iron deficiency was present in half of patients scheduled for major surgery. However, few treatments to correct iron deficiency were implemented preoperatively or postoperatively. There is an urgent need for action to improve these outcomes, including better patient blood management.

Myeloid FTH1 Deficiency Protects Mice From Colitis and Colitis-associated Colorectal Cancer via Reducing DMT1-Imported Iron and STAT3 Activation

BACKGROUND

Myeloid cells are critical for iron and immune homeostasis. Ferritin heavy chain (FTH1) is essential for intracellular iron storage. Myeloid FTH1 is important in the pathogenesis of many inflammatory diseases. However, the role of myeloid FTH1 in colitis and colitis-associated cancer has not been determined.

METHODS

Myeloid FTH1 deficient and wild-type mice were treated with dextran sodium sulfate (DSS) or azoxymethane (AOM)-DSS to compare their susceptibility to acute colitis or colitis-associated cancer.

RESULTS

Myeloid FTH1-deficient mice fed with a high-iron diet were less susceptible to DSS-induced acute colitis than wild type mice. Mechanistic studies showed that myeloid FTH1 deficiency resulted in lower expression of an iron uptake protein divalent metal transporter 1 (DMT1) and active phosphorylated signal transducer and activator of transcription 3 (STAT3) in the colon tissues. Our studies also showed that pharmacological STAT3 reactivation restored the susceptibility of myeloid FTH1-deficient mice to DSS-induced acute colitis. Consistently, myeloid FTH1-deficient mice fed with a high-iron diet had reduced DMT1, phosphorylated STAT3 and inflammation in their colon tissues, and were less susceptible to colitis-associated colorectal cancer.

CONCLUSIONS

Our study demonstrated that myeloid FTH1 is required for colitis and colitis-associated colorectal cancer via maintaining of DMT1-iron-STAT3 signaling activation under excess iron condition.

Iron Deficiency Anemia in Colorectal Cancer Patients: Is Preoperative Intravenous Iron Infusion Indicated? A Narrative Review of the Literature

Iron deficiency anemia is the most common extraintestinal symptom in patients with colorectal cancer (CRC). Inflammation associated with malignancy leads to functional iron deficiency via the hepcidin pathway, whereas chronic blood loss causes absolute iron deficiency and depletion of iron stores. The assessment and treatment of preoperative anemia is of great importance in patients with CRC, since published data have consistently shown that preoperative anemia is associated with increased need for perioperative blood transfusions and more postoperative complications. Recent studies have documented mixed results regarding the preoperative intravenous iron administration in anemic CRC patients in terms of efficacy for anemia correction, cost-effectiveness, need for transfusions and risk for postoperative complications.

A protocol for a prospective, multicentre observational study to determine if nonanaemic iron deficiency worsens postoperative outcome in patients undergoing elective surgery for resection of colorectal cancer: The NATO study

BACKGROUND

Preoperative absolute and functional iron deficiency anaemia is associated with poor postoperative outcomes in patients undergoing surgery for colorectal cancer. It is biologically plausible that "early", or "nonanaemic" iron deficiency may also be associated with worse postoperative outcomes in similar cohorts, albeit at lesser severity than that seen for anaemia. The evidence supporting this assertion is of low quality.

METHODS

We have designed a prospective, observational study to delineate associations between preoperative non-anaemic iron deficiency and postoperative outcomes after surgery for colorectal cancer. Patients without anaemia, undergoing elective surgery for colorectal cancer will be allocated to an iron replete or an iron deficient group based on preoperative transferrin saturation. The primary outcome is days alive and at home on postoperative day 90. Secondary outcomes include days alive and at home on postoperative day 30, length of hospital stay, readmission to acute care, postoperative complications, health-related quality of life scores, quality of postoperative recovery, and requirement for allogeneic blood transfusion. The planned sample size is 422 patients, which has 80% power to detect a two-day difference in the primary outcome. The study commenced in May 2019.

CONCLUSION

The results of this study will provide patients and clinicians with high-quality evidence concerning associations between nonanaemic iron deficiency and patient-centred outcomes after surgery for colorectal cancer. The study will be conducted in multiple urban and rural centres across Australia and New Zealand. The results will be highly generalisable to contemporary surgical practice and should be rapidly translated.

Iron metabolism in colorectal cancer

Iron, as one of the essential trace elements in the human body, is involved in a wide range of critical biochemical reactions and physiological processes, including the maintenance of the normal cell cycle, mitochondrial function, nucleotide metabolism, and immune response. In this context, iron is naturally associated with cancer occurrence. Cellular iron deficiency can induce apoptosis, however, iron can also engage in potentially harmful reactions that produce free radicals because of its capacity to gain and lose electrons. Studies suggest that dietary iron, particularly heme iron, may be one of the leading causes of colorectal cancer (CRC). Moreover, patients with CRC have abnormal iron absorption, storage, utilization, and exportation. Therefore, iron is crucial for the development and progression of CRC. Elaborating on the alterations in iron metabolism during the onset and advancement of CRC would help to further explain the role and mechanism of iron inside the body. Thus, we reviewed the alterations in numerous iron metabolism-related molecules and their roles in CRC, which may provide new clues between iron metabolism and CRC.

Oxidative Stress and DNA Damage Markers in Colorectal Cancer

Oxidative stress (OS) and inflammation are known to play an important role in chronic diseases, including cancer, and specifically colorectal cancer (CRC). The main objective of this study was to explore the diagnostic potential of OS markers in patients with CRC, which may translate into an early diagnosis of the disease. To do this, we compared results with those in a group of healthy controls and assessed whether there were significant differences. In addition, we explored possible correlations with the presence of tumors and tumor stage, with anemia and with inflammatory markers used in clinical practice. The study included 80 patients with CRC and 60 healthy controls. The following OS markers were analyzed: catalase (CAT), reduced glutathione (GSH) and oxidized glutathione (GSSG) in serum; and 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-oxodG) and F2-isoprotanes in urine (F2-IsoPs). Tumor markers (CEA and CA 19.9), anemia markers (hemoglobin, hematocrit and medium corpuscular volume) and inflammatory markers (leukocytes, neutrophils, N/L index, platelets, fibrinogen, C-reactive protein, CRP and IL-6) were also determined. Comparison of means between patients and controls revealed highly significant differences for all OS markers, with an increase in the prooxidant markers GSSG, GSSG/GSH ratio, 8-oxodG and F2-IsoPs, and a decrease in the antioxidant markers CAT and GSH. Tumor and inflammatory markers (except CRP) correlated positively with GSSG, GSSG/GSH ratio, 8-oxodG and F2-IsoPs, and negatively with CAT and GSH. In view of the results obtained, OS markers may constitute a useful tool for the early diagnosis of CRC patients.

Iron deficiency screening is a key issue in chronic inflammatory diseases: A call to action

Iron deficiency is frequent in patients with chronic inflammatory conditions (e.g., chronic heart failure, chronic kidney disease, cancers, and bowel inflammatory diseases). Indeed, high concentrations of inflammatory cytokines increase hepcidin concentrations that lead to the sequestration of iron in cells of the reticuloendothelial system (functional iron deficiency). Iron parameters are often assessed only in the context of anemia, but iron deficiency, even without anemia, is present in about half of patients with inflammatory conditions. Iron deficiency worsens underlying chronic diseases and is an independent factor of morbidity and mortality. In daily practice, the most effective biomarkers of iron status are serum ferritin, which reflects iron storage, and transferrin saturation, which reflects the transport of iron. Serum ferritin is increased in an inflammatory context, and there is still no consensus on the threshold to be used in chronic inflammatory conditions. Nevertheless, recent recommendations of international guidelines agreed to define iron deficiency by serum ferritin &lt;100 µg/L and/or transferrin saturation &lt;20%. Iron parameters remain, however, insufficiently assessed in patients with chronic inflammatory conditions. Indeed, clinical symptoms of iron deficiency, such as fatigue, are not specific and often confused with those of the primary disease. Iron repletion, preferably by the intravenous route to bypass tissue sequestration, improves clinical signs and quality of life. Because of the negative impact of iron deficiency on chronic inflammatory diseases and the efficacy of intravenous iron repletion, screening of iron parameters should be part of the routine examination of all patients with chronic inflammatory diseases.

Absolute and Functional Iron Deficiency in Colon Cancer: A Cohort Study

Background and Objectives: Iron is an essential micronutrient for many biological functions and has been found to be intimately linked to cancer biology. Although the effects of increased dietary iron consumption in the development of CRC have been previously investigated in several cohort studies, the available evidence on the involvement of iron deficiency in this process is relatively scarce. Previously published papers did not analyze specific outcomes, such as the presence of biologically aggressive histopathological characteristics, that are associated with the subtypes of iron deficiency. The purpose of this study was to investigate the connection between the development of colorectal cancer and the presence of functional iron deficiency (FID), which is defined as insufficient biological availability of iron in the presence of adequate storage reserves, or absolute iron deficiency (AID), which is defined as severely depleted iron storage levels. Materials and Methods: Our paper represents a single center registry-based cohort study. Iron levels were routinely evaluated upon diagnosis of CRC and the collected data were coupled with patient- and tumor-specific data (2018–2022). Spearman’s correlation coefficient and the chi-squared test were used to analyze the association. Results: Out of 129 patients, 75 (58.13%) were anemic. AID was identified in 26.35% of cases and FID was encountered in 51.16% of cases. A statistically significant association between FID and lymphatic invasion was encountered. An analysis of the correlation demonstrated a significant association between anemia and right-sided tumor location. Conclusions: Functional iron deficiency seems to be independently associated with lymphatic invasion. Although a statistically significant correlation with the T or N stage was not demonstrated, the analysis suggested a potential positive relationship between the presence of FID and more aggressive tumor characteristics.

Long-term survival in colorectal liver metastasis

INTRODUCTION

Liver resection is the best treatment option for patients with resectable colorectal liver metastasis (CRLM). A 10-year follow-up can reflect the true curative potential of resection. This retrospective study investigated factors for long-term survival of CRLM patients.

METHOD

Data of patients who underwent liver resection for CRLM without extrahepatic disease from 1990 to 2012 at our hospital were reviewed. Patients who survived for > 10 years were compared with those who survived for < 10 years.

RESULTS

Totally, 315 patients were included in the study. They were divided into 2 groups: < 10-year group and > 10-year group. Patients in the < 10-year group had more tumor nodules (P = 0.016), more bilobar involvement (P = 0.004), narrower resection margin (P < 0.001), and worse disease-free and overall survival (P < 0.001). On multivariate analysis, low preoperative hemoglobin level, large number of tumor nodules, and bilobar involvement were poor prognostic factors for overall survival, while adjuvant chemotherapy was a favorable factor. Further analysis of patients with bilobar disease showed that perioperative blood transfusion was a poor prognostic factor for overall survival while adjuvant chemotherapy was a favorable one. In patients with multiple bilobar tumor nodules, adjuvant chemotherapy had a positive impact on disease-free survival and overall survival.

CONCLUSIONS

Patients who survived for > 10 years after liver resection for CRLM tended to have normal preoperative hemoglobin level, unilobar disease, fewer tumor nodules, and have received adjuvant chemotherapy. Adjuvant chemotherapy favorably affected long-term survival of CRLM patients.

Perioperative changes in haemoglobin and ferritin concentrations from preoperative intravenous iron isomaltoside for iron deficiency anaemia in patients with colorectal cancer: A pilot randomised controlled trial

Background

Patients with colorectal cancer have a high risk of iron deficiency anaemia (IDA) due to chronic tumour induced blood loss, a reduced dietary iron intake from poor nutrition or gastrointestinal malabsorption. This pilot, double blinded, randomised controlled trial (RCT) examined the effect and feasibility of using preoperative iron isomaltoside for treating iron deficiency anaemia.

Methods

Forty eligible adults with IDA were randomised to receive either intravenous iron isomaltoside (20 mg.kg^-1 up to 1000 mg over 30 minutes) or usual preoperative care (control) three weeks before scheduled colorectal surgery. The primary outcomes were perioperative changes in haemoglobin and ferritin concentrations.

Results

The recruitment rate was 78% of all eligible referred patients (1.9 patients/month). The haemoglobin and ferritin concentrations were higher in the iron isomaltoside group than the control group over the perioperative period (group*time interaction P = 0.042 and P < 0.001 respectively). Mean haemoglobin change from baseline to before surgery was higher in the iron isomaltoside group (7.8, 95% CI: 3.2 to 12.3 g.l^-1) than the control group (1.7, 95% CI: -1.9 to 5.3 g.l^-1) [mean difference 6.1, 95% CI: 0.3 to 11.8 g.l^-1; P = 0.040]. The ferritin change from baseline to before surgery between groups was large in favour of the iron isomaltoside group (mean difference 296.9, 95% CI: 200.6 to 393.2 μg.l^-1; P < 0.001]. There were no differences between groups in packed red blood cell transfusions needed, surgical complications, quality of recovery and days (alive and) at home within 30 days after surgery.

Conclusion

Iron isomaltoside therapy was safe and had a minimal effect on perioperative changes in haemoglobin concentration. Given the slow recruitment and new evidence emerging during the conduct of this study, conducting a multi-centre RCT based on the current pilot trial protocol is unlikely to be feasible.

Trial registration

ClinicalTrials.gov NCT03565354.

Risk Nomogram Does Not Predict Anastomotic Leakage After Colon Surgery Accurately: Results of the Multi-center LekCheck Study

PURPOSE

Anastomotic leakage (AL) is a dreaded complication after colorectal surgery. Preoperatively identifying high-risk patients can help to reduce the incidence of this complication. For this reason, AL risk nomograms have been developed. The objective of this study was to test the AL risk nomogram developed by Frasson, et al. for validity and to identify risk-factors for AL.

METHODS

From the international multi-center LekCheck study database, patients who underwent colonic surgery with the formation of an anastomosis were included. Data were prospectively collected between 2016 and 2019 at 14 hospitals. Univariate and multivariable regression analyses, and area under receiver operating characteristic curve analysis (AUROC) were performed.

RESULTS

A total of 643 patients were included. The median age was 70 years and 51% were male. The majority underwent surgery for malignancies (80.7%). The overall AL rate was 9.2%. The risk nomogram was not predictive for AL in the population tested (AUROC 0.572). Low preoperative haemoglobin (p = 0.006), intraoperative hypothermia (p = 0.02), contamination of the operative field (p = 0.004), and use of epidural analgesia (p = 0.02) were independent risk-factors for AL.

CONCLUSION

The AL risk nomogram could not be validated using the international LekCheck study database. In the future, intraoperative predictive factors for AL, as identified in this study, should also be included in AL risk predictors.

The prognostic impact of preoperative mean corpuscular volume in colorectal cancer

OBJECTIVE

The relationship between preoperative mean corpuscular volume and postoperative prognosis has been reported in some cancers recently, but no certain consensus has been reached, especially for colorectal cancer. We evaluated the usefulness of mean corpuscular volume as a prognostic factor in colorectal cancer patients.

METHODS

This study included 1003 patients with colorectal cancer who underwent curative surgery in a single institution. The relationship between mean corpuscular volume values and postoperative recurrence was evaluated by fractional polynomial model. Based on the result, patients were divided into groups according to mean corpuscular volume values. Clinicopathological factors and long-term outcomes were compared between the groups.

RESULTS

The risk of postoperative recurrence according to mean corpuscular volume value showed a J-shaped curve, suggesting that both low and high mean corpuscular volume have high risk. Low mean corpuscular volume (≤84 fl) group was oncologically advanced in terms of pathological tumor stage, histological grade and lymphatic invasion with higher inflammation markers. High mean corpuscular volume (>95 fl) group had higher frequency of drinking habit with higher values of aspartate aminotransferase, alanine aminotransferase and γ-glutamyl transpeptidase. Abnormal mean corpuscular volume group including these two groups showed significantly worse disease-free survival than the other (P < 0.001). Multivariate analysis suggested that abnormal mean corpuscular volume was an independent risk factor for postoperative recurrence (hazard ratio, 1.344; 95% confidence interval, 1.005-1.796; P = 0.046). Furthermore, its prognostic impact was more significant in pStage III than in other stages.

CONCLUSION

Preoperative low and high mean corpuscular volume is a poor prognostic factor in colorectal cancer patients. It could be a predictive marker to estimate worse survival outcome after surgery.

Phenome-wide association study (PheWAS) of colorectal cancer risk SNP effects on health outcomes in UK Biobank

BACKGROUND

Associations between colorectal cancer (CRC) and other health outcomes have been reported, but these may be subject to biases, or due to limitations of observational studies.

METHODS

We set out to determine whether genetic predisposition to CRC is also associated with the risk of other phenotypes. Under the phenome-wide association study (PheWAS) and tree-structured phenotypic model (TreeWAS), we studied 334,385 unrelated White British individuals (excluding CRC patients) from the UK Biobank cohort. We generated a polygenic risk score (PRS) from CRC genome-wide association studies as a measure of CRC risk. We performed sensitivity analyses to test the robustness of the results and searched the Danish Disease Trajectory Browser (DTB) to replicate the observed associations.

RESULTS

Eight PheWAS phenotypes and 21 TreeWAS nodes were associated with CRC genetic predisposition by PheWAS and TreeWAS, respectively. The PheWAS detected associations were from neoplasms and digestive system disease group (e.g. benign neoplasm of colon, anal and rectal polyp and diverticular disease). The results from the TreeWAS corroborated the results from the PheWAS. These results were replicated in the observational data within the DTB.

CONCLUSIONS

We show that benign colorectal neoplasms share genetic aetiology with CRC using PheWAS and TreeWAS methods. Additionally, CRC genetic predisposition is associated with diverticular disease.

Hematinic and Iron Optimization in Peri-operative Anemia and Iron Deficiency

Purpose of Review

Preoperative anemia is independently associated with worse postoperative outcomes following cardiac and noncardiac surgery. This article explores the current understanding of perioperative anemia and iron deficiency with reference to definition, diagnosis, and treatment.

Recent Findings

Iron deficiency is the most common cause of anemia. It can arise from reduced iron intake, poor absorption, or excess iron loss. Inflammation throughout the preoperative period can drive iron sequestration, leading to a functional deficiency of iron and the development of what was referred to until recently as the “anemia of chronic disease.” Current best practice guidance supports the routine administration of preoperative intravenous iron to treat anemia despite limited evidence. This “one size fits all” approach has been called into question following results from a recent large, randomized trial (the PREVENTT trial) that assessed the use of a single dose of intravenous iron compared to placebo 10–42 days before major abdominal surgery. Although there were no improvements in patient-centered outcomes apparent during the initial hospital stay, secondary endpoints of this trial suggested there may be some late benefit after discharge from the hospital (8 weeks postoperatively). This trial raises questions on (1) the mechanisms of iron deficiency in the perioperative patient; (2) the need to reassess our opinions on generic anemia management; and (3) the need to address patient outcomes after discharge from hospital.

Summary

Despite the known associations between preoperative anemia (particularly iron deficiency anemia) and poor postoperative outcome, recent evidence suggests that administering intravenous iron relatively close to surgery does not yield a tangible short-term benefit. This is made more complex by the interplay between iron and innate immunity. Iron deficiency irrespective of hemoglobin concentration may also impact postoperative outcomes. Therefore, further research into associations between iron deficiency and postoperative outcomes, and between postoperative anemia, delayed outcomes (hospital readmission), and the efficacy of postoperative intravenous iron is required.

Preoperative intravenous iron treatment reduces postoperative complications and postoperative anemia in preoperatively anemic patients with colon carcinoma

PURPOSE

Anemia is common among patients with colorectal cancer and is associated with an increased risk of complications and poorer survival rate. The main objective of our study was to determine the effect of preoperative intravenous iron supplementation therapy on the need for red blood cell transfusions, other postoperative complications, and length of hospital stay in colon cancer patients undergoing colon resection.

METHODS

In this retrospective cohort study, data were collected from medical records of all 549 colon carcinoma patients who underwent a colon resection in Helsinki University Hospital during the years 2017 and 2018. The patients were divided into two cohorts: one with anemic patients treated with preoperative intravenous iron supplementation therapy (180 patients) and one with anemic patients without preoperative intravenous iron supplementation therapy (138 patients). Non-anemic patients and patients requiring emergency surgery were excluded (231 patients).

RESULTS

Patients treated with intravenous iron had less postoperative complications (33.9% vs. 45.9%, p = 0.045) and a lower prevalence of anemia at 1 month after surgery (38.7% vs. 65.3%, p < 0.01) when compared with patients without preoperative iv iron treatment. No difference was found in the amount of red blood cell transfusions, length of stay, or mortality between the groups.

CONCLUSION

This is the first study demonstrating a significant decrease in postoperative complications in anemic colon cancer patients receiving preoperative intravenous iron supplementation therapy. This treatment also diminishes the rate of postoperative anemia, which is often associated with a facilitated recovery.

Efficacy and cost-effectiveness of universal pre-operative iron studies in total hip and knee arthroplasty

Background

The prevalence of anaemia in patients planned for total hip and knee arthroplasty is about 20%. Optimising pre-operative haemoglobin levels by iron supplementation has been shown to decrease transfusion rates, complications and associated morbidity. The need for universal screening with iron studies of all elective arthroplasty patients is not clearly defined at present.

Methods

Retrospective review of 2 sequential cohorts of patients undergoing primary hip or knee arthroplasty by a single surgeon at a single centre between January 2013 and December 2017. The first group of patients underwent pre-operative iron studies only if found to be anaemic, with a haemoglobin below 12g/dl. From January 2015, all patients irrespective of the presence of anaemia were screened with a complete iron profile before surgery. Patients with a confirmed iron deficiency were administered with intravenous iron prior to surgery. The 2 cohorts were compared with regard to blood transfusion rate post-operatively and cost efficiency for universal screening with iron studies.

Results

There was a net decrease in the allogenic blood transfusion rate from 4.76 to 2.92% when universal iron studies were introduced but the difference was not statistically significant. Obtaining universal pre-operative iron studies is cost neutral with the price of allogenic blood transfusion in a similar cohort. We also diagnosed 5 patients with occult malignancies.

Conclusions

Universal screening with pre-operative iron studies and iron infusion in elective arthroplasty patients may reduce allogenic blood requirements and is cost neutral. An additional benefit is the potential to diagnose asymptomatic malignancies. Further studies are required to show the true benefit of universal pre-operative iron screening.

Preoperative hemoglobin count and prognosis of esophageal cancer, a population-based nationwide study in Finland

BACKGROUND

The prognostic value of preoperative hemoglobin in patients undergoing esophagectomy is unknown. The aim of this study was to examine whether preoperative hemoglobin is associated with prognosis in patients undergoing esophagectomy for cancer.

MATERIALS AND METHODS

This was a population-based nationwide retrospective cohort study in Finland, using Finnish National Esophago-Gastric Cancer Cohort (FINEGO). Esophagectomy patients with available preoperative hemoglobin measurement were included. Multivariable cox regression provided hazard ratios (HR) with 95% confidence intervals (CI), adjusted for calendar period of surgery, age at surgery, sex, comorbidity (Charlson Comorbidity Index), tumor histology, tumor stage, neoadjuvant therapy, type of surgery (minimally invasive or open) and annual hospital volume.

RESULTS

Of the 1313 patients, 932 (71.0%) were men and 799 (60.9%) had esophageal adenocarcinoma. Overall all-cause mortality was significantly higher in the lowest hemoglobin count tertile (HR 1.26 (1.07-1.47)) compared to the highest tertile, but this association was attenuated after adjustment for confounding. No differences were found between the preoperative hemoglobin groups in the adjusted analyses of 90-day all-cause, 5-year all-cause, and 5-year cancer-specific mortality.

CONCLUSION

In this population-based nationwide study, preoperative hemoglobin count had no independent prognostic significance in esophageal cancer.

Iron deficiency, immunology, and colorectal cancer

Excessive gut luminal iron contributes to the initiation and progression of colorectal cancer. However, emerging evidence suggests that reduced iron intake and low systemic iron levels are also associated with the pathogenesis of colorectal cancer. This is important because patients with colorectal cancer often present with iron deficiency. Iron is necessary for appropriate immunological functions; hence, iron deficiency may hinder cancer immunosurveillance and potentially modify the tumor immune microenvironment, both of which may assist cancer development. This is supported by studies showing that patients with colorectal cancer with iron deficiency have inferior outcomes and reduced response to therapy. Here, we provide an overview of the immunological consequences of iron deficiency and suggest ensuring adequate iron therapy to limit these outcomes.

Iron deficiency in colorectal cancer patients: a cohort study on prevalence and associations

AIM

The aim of this work was to estimate the prevalence of iron deficiency in patients diagnosed with colorectal cancer (CRC) and to clarify its association with patient- and tumour-related characteristics.

METHOD

This was a single-centre registry-based cohort study. Iron status was routinely evaluated upon diagnosis of CRC, and these data were coupled with patient- and tumour-specific data from the Danish CRC Group Registry (2013-2018). Data were analysed using multivariate logistic regression.

RESULTS

Out of 846 patients, 543 (64%) were iron deficient. There was an association between increasing depth of invasion and iron deficiency, with odds ratios (ORs) of iron deficiency being 2.8 (p = 0.001, CI 1.5-5.1), 4.22 (p < 0.001, CI 2.48-7.18) and 4.63 (p < 0.001, CI 2.30-9.34) for T-stages 2, 3 and 4, respectively. Right-sided tumours had an OR of 3.54 (p < 0.001, CI 2.22-5.67) of iron deficiency compared with left-sided tumours. Tumours diagnosed through the national CRC screening programme were less likely to be associated with iron deficiency (OR 0.34, CI 0.22-0.52), while female gender was associated with an increase in the odds for iron deficiency (OR 1.91, CI 1.33-2.76). Iron deficiency was prevalent in 88% of anaemic patients and 43% of nonanaemic patients.

CONCLUSION

Iron deficiency was highly prevalent in patients diagnosed with CRC. Increased depth of tumour invasion, right-sided location and female gender were all associated with higher odds for iron deficiency, while patients diagnosed through the national screening programme were associated with lower odds for iron deficiency. A large proportion of patients with a normal haemoglobin were also iron deficient.

Oral and Intravenous Iron Therapy Differentially Alter the On- and Off-Tumor Microbiota in Anemic Colorectal Cancer Patients

Iron deficiency anemia is a common complication of colorectal cancer and may require iron therapy. Oral iron can increase the iron available to gut bacteria and may alter the colonic microbiota. We performed an intervention study to compare oral and intravenous iron therapy on the colonic tumor-associated (on-tumor) and paired non-tumor-associated adjacent (off-tumor) microbiota. Anemic patients with colorectal adenocarcinoma received either oral ferrous sulphate (n = 16) or intravenous ferric carboxymaltose (n = 24). On- and off-tumor biopsies were obtained post-surgery and microbial profiling was performed using 16S ribosomal RNA analysis. Off-tumor α- and β-diversity were significantly different between iron treatment groups. No differences in on-tumor diversity were observed. Off-tumor microbiota of oral iron-treated patients showed higher abundances of the orders Clostridiales, Cytophagales, and Anaeroplasmatales compared to intravenous iron-treated patients. The on-tumor microbiota was enriched with the orders Lactobacillales and Alteromonadales in the oral and intravenous iron groups, respectively. The on- and off-tumor microbiota associated with intravenous iron-treated patients infers increased abundances of enzymes involved in iron sequestration and anti-inflammatory/oncogenic metabolite production, compared to oral iron-treated patients. Collectively, this suggests that intravenous iron may be a more appropriate therapy to limit adverse microbial outcomes compared to oral iron.

Energy and Protein Intake After Return Home in Colorectal Surgery Patients With an Enhanced Recovery Program: A Prospective Observational Study

BACKGROUND

In patients scheduled for colorectal surgery with an enhanced recovery program (ERP), feeding after returning home has been insufficiently investigated. The aim of this study was to measure energy and protein intake during the first month at home.

METHODS

Seventy adult patients scheduled for colorectal surgery with ERP were included. Calorie and protein intakes were calculated, and body weight was measured preoperatively and 3, 7, 15, and 30 days after discharge home. Data are mean ± SD or median (interquartile range).

RESULTS

Patient characteristics were age 60.0 ± 15.0 years, BMI = 25.9 ± 5.5 kg/m² , and colon/rectum of 56/14. The duration of hospitalization was 3 (2-5) days. Calorie and protein intakes (21.9 [17.7-28.6] kilocalorie per kilogram of ideal body weight [kcal/kg IBW] and 0.81 [0.61-1.14] g/kg IBW) were significantly reduced (P < .01) by 15% on day 3, compared with preoperative values, and then increased gradually to reach preoperative values after 1 month. Almost 50% of the patients failed to reach the calorie intake target of 25 kcal/kg IBW, and almost no patient reached the protein intake target of 1.5 g/kg IBW 30 days after discharge home. Weight loss after 30 days at home remained at -1.8 ± 2.7 kg.

CONCLUSIONS

Colorectal surgery, even in an ERP, is associated with energy and protein intake below the targets recommended for the rehabilitation phase and results in weight loss. Whether nutrition counseling and prolonged administration of protein-enriched oral supplements could accelerate weight gain needs to be explored.

Effect of anaemia on the response to preoperative chemoradiotherapy for rectal cancer

BACKGROUNDS

Radiation therapy with concurrent chemotherapy is an important treatment for rectal cancer, especially for advanced stage disease. Low serum haemoglobin levels are accepted as a negative indicator in the response to radiation therapy. This study aimed to evaluate the relationship between anaemia and the response to preoperative chemoradiotherapy for rectal cancer and its effect on oncologic outcomes.

METHODS

We retrospectively reviewed medical records of primary rectal cancer patients who were treated with preoperative chemoradiotherapy followed by total mesorectal excision between January 2011 and December 2015. Anaemia was defined as serum haemoglobin levels ≤9 g/dL before or during radiotherapy. Patients were divided into good and poor responders according to pathologic tumour regression grades. The effect of anaemia on the response to radiation therapy, recurrence-free survival and overall survival were analysed after subgroup analysis.

RESULTS

Overall, 301 and 394 patients were categorized into good and poor responder groups, respectively. Proportions of anaemia patients were higher in the poor responder group than in the good responder group (7.6% versus 4.0%, P = 0.042). Anaemia was associated with less pathologic complete regression but was not a risk factor for worse recurrence-free or overall survival. There was no significant difference in survival between patients with and without anaemia.

CONCLUSION

Haemoglobin levels ≤9 g/dL before or during radiotherapy were risk factors for achieving pathologic complete regression after preoperative chemoradiotherapy for rectal cancer. However, anaemia was not independently associated with worse survival outcomes.

Preoperative intravenous iron therapy and survival after colorectal cancer surgery: long-term results from the IVICA randomised controlled trial

AIM

Preoperative iron is frequently used for the correction of anaemia in colorectal cancer surgery. However, enteral iron intake may promote tumour growth and progression which could influence cancer recurrence and patient survival. We explore the long-term outcomes of patients receiving either oral or intravenous iron replacement therapy as part of a previous randomized controlled trial.

METHODS

The IVICA trial randomized anaemic colorectal cancer patients to receive either oral (OI, control) or intravenous (IVI, treatment) iron prior to their elective operation. Follow-up analysis of all patients recruited to this multicentre trial who underwent surgical resection with curative intent was performed. Kaplan-Meier survival estimates and Cox proportional hazard models were used to compare groups. A pooled group multivariable analysis comparing patients who achieved resolution of anaemia preoperatively to those who did not was also undertaken.

RESULTS

In all, 110 of the 116 patients previously enrolled were eligible for analysis (OI n = 56, IVI n = 54). Median overall follow-up duration was 61 months (interquartile range 46-67). No significant difference in 5-year overall survival (hazard ratio (HR) 1.22, 95% CI 0.65-2.28, P = 0.522) or disease-free survival (HR 1.08, 95% CI 0.61-1.92, P = 0.79) was observed between OI and IVI. A pooled analysis of treatment groups found that preoperative resolution of anaemia led to improved 5-year overall survival on multivariable analysis (HR 3.38, 95% CI 1.07-11.56, P = 0.044).

CONCLUSION

We recommend IVI for the preoperative correction of anaemia. Route of iron therapy did not significantly influence survival. Preoperative anaemia correction may lead to an overall survival advantage following elective colorectal cancer surgery.

Influence of Iron on the Gut Microbiota in Colorectal Cancer

Perturbations of the colonic microbiota can contribute to the initiation and progression of colorectal cancer, leading to an increase in pathogenic bacteria at the expense of protective bacteria. This can contribute to disease through increasing carcinogenic metabolite/toxin production, inducing inflammation, and activating oncogenic signaling. To limit disease progression, external factors that may influence the colonic microbiota need to be considered in patients with colorectal cancer. One major factor that can influence the colonic microbiota is iron. Iron is an essential micronutrient that is required by both prokaryotes and eukaryotes for cellular function. Most pathogenic bacteria have heightened iron acquisition mechanisms and therefore tend to outcompete protective bacteria for free iron. Colorectal cancer patients often present with anemia due to iron deficiency, and thus they require iron therapy. Depending upon the route of administration, iron therapy has the potential to contribute to a procarciongenic microbiota. Orally administered iron is the common treatment for anemia in these patients but can lead to an increased gut iron concentration. This suggests the need to reassess the route of iron therapy in these patients. Currently, this has only been assessed in murine studies, with human trials being necessary to unravel the potential microbial outcomes of iron therapy.

Intravenous Iron in a Prehabilitation Program for Older Surgical Patients: Prospective Cohort Study

BACKGROUND

Older patients often have iron deficiency anemia before surgery, which can be effectively treated with intravenous iron supplementation (IVIS). Anemia and blood transfusions are associated with an increased risk of delirium. The aim of this research was to assess the effectiveness and safety of using IVIS in a prehabilitation program.

MATERIAL AND METHODS

Patients ≥70 y who underwent abdominal surgery between November 2015 and June 2018 were included in this single-center prospective cohort study. All patients were prehabilitated; however, only anemic patients received a single dose of 1000 mg intravenous iron (ferric carboxymaltose) to increase preoperative hemoglobin levels (IVIS group). Nonanemic patients received standard care (SC). The hemoglobin levels (primary outcome) were assessed at the outpatient clinic visit, at admission, and at discharge. Secondary outcomes were postoperative delirium, postoperative anemia, blood transfusion, complications other than delirium, and length of hospital stay. All outcomes were compared between the IVIS group and SC group.

RESULTS

Of all patients (n = 248), 97 anemic patients received IVIS (39%). Of the anemic patients, 50 patients (52%) had iron deficiency. Initial differences in hemoglobin concentrations between the IVIS group and SC group at T1 and T2 (7.2 versus 8.8; P < 0.001 and 7.4 versus 8.6; P = 0.023, respectively) were no longer present at discharge (6.6 versus 7.2; P = 0.35). No statistically significant differences were observed for all secondary outcomes between the IVIS group and the SC group. No infusion-related adverse events occurred.

CONCLUSIONS

Adding IVIS to prehabilitation programs is safe and diminishes differences in these concentrations between preoperatively anemic and nonanemic patients. IVIS may be worthwhile as an additional component of prehabilitation programs. Results merit further investigation.

Anaemia in patients undergoing major bowel surgery - Prevalence and current practice: A public and private institution experience

AIM

The study aimed to compare the frequency and alignment of preoperative anaemia screening and treatment with Australian guidelines in elective bowel surgery and determine the impact on clinical outcomes.

METHODS

We performed a retrospective observational study, with an audit of 559 adult patients who underwent major elective bowel surgery in an Australian metropolitan hospital, January 2016-December 2018. Outcome measures included rate of anaemia, guideline compliance, hospital length of stay, and transfusion rate.

RESULTS

Preoperative anaemia assessment occurred in 82.6% of patients. However, only 5.2% received recommended biochemical tests at least one week before surgery. Only 25.2% of anaemic patients received preoperative treatment; they experienced a longer hospital length of stay (9.93 days versus 7.88 days, p < 0.001) and an increased rate of transfusion (OR: 3.186, p < 0.05).

CONCLUSION

The gaps between current preoperative anaemia screening, management and national guidelines may place patients at higher risk of poor surgical outcome.

Use of intravenous iron therapy in colorectal cancer patient with iron deficiency anemia: a propensity-score matched study

PURPOSE

Iron deficiency anemia is common in colorectal cancer patients and is related to poor surgical outcome. Increasing evidence supports preoperative use of intravenous iron (IVI) to correct anemia. Our study investigates effect of preoperative IVI on hemoglobin level.

METHODS

From August 2017 to March 2019, colorectal cancer patients with iron deficiency anemia received intravenous iron at least 2 weeks before their scheduled operations (IVI group). These patients' prospectively collected data were compared to a historic cohort of anemic patients who received elective colorectal surgery within 3 years before the study period (non-IVI).

RESULTS

Forty-six patients were included after receiving intravenous iron. After propensity score matching on 1:2 ratio, 38 patients in IVI group were matched with 62 patients from non-IVI group. There was no statistical difference for preoperative mean hemoglobin level between the two groups (8.43 g/dL in IVI, 8.79 g/dL in non-IVI, p = 0.117), but IVI group has significantly higher mean hemoglobin level on admission (10.63 g/dL in IVI, 9.46 g/dL in non-IVI, p = < 0.001). IVI group had higher median hemoglobin rise (1.9 in IVI, 0.6 in non-IVI, p = <0.001) and significantly less red cell transfusion (8 patients in IVI, 30 in non-IVI, p = 0.006). Subgroup analysis showed that less patients in IVI group required transfusions in preoperative period (1 in IVI group, 20 in non-IVI, p < 0.001).

CONCLUSION

Our data suggested that IVI can significantly increase hemoglobin level in iron deficiency anemic patients before colorectal surgery, with reduction in red cell transfusions.

Iron deficiency in children at the time of initial neuroblastoma diagnosis

IMPORTANCE

There is a high incidence of iron deficiency in children worldwide. Notably, however, while iron deficiency is the most common cause of anemia, little is known about the prevalence and different types of iron deficiency in neuroblastoma patients.

OBJECTIVE

The aim of the present study was to investigate the prevalence of iron deficiency in patients newly diagnosed with neuroblastoma.

METHODS

A total of 195 newly diagnosed neuroblastoma patients from November 2015 to January 2018 were analyzed retrospectively. The survival analysis was estimated by the Kaplan-Meier method.

RESULTS

Of the 195 neuroblastoma patients included in the study, 121 (62.1%) had iron deficiency, 55 (28.2%) had absolute iron deficiency, and 66 (33.9%) had functional iron deficiency. Being aged ≥ 18 months, tumor originating in the abdomen, International Neuroblastoma Risk Group Staging System M, high-risk neuroblastoma, lactate dehydrogenase ≥ 1500 U/L, neuron-specific enolase ≥ 100 U/L, unfavorable histologic category, MYCN amplification, chromosome 1p loss, and bone marrow metastasis were associated with significantly higher rates of functional iron deficiency (P < 0.05).

INTERPRETATION

Functional iron deficiency at the time of initial neuroblastoma diagnosis predicted lower event-free survival. Long-term effects of iron supplementation in neuroblastoma patients with different types of iron deficiency need to be further studied.

Iron Status and Cancer Risk in UK Biobank: A Two-Sample Mendelian Randomization Study

We conducted a two-sample Mendelian randomization study to explore the associations of iron status with overall cancer and 22 site-specific cancers. Single-nucleotide polymorphisms for iron status were obtained from a genome-wide association study of 48,972 European-descent individuals. Summary-level data for breast and other cancers were obtained from the Breast Cancer Association Consortium and UK Biobank. Genetically predicted iron status was positively associated with liver cancer and inversely associated with brain cancer but not associated with overall cancer or the other 20 studied cancer sites at p < 0.05. The odds ratios of liver cancer were 2.45 (95% CI, 0.81, 7.45; p = 0.11), 2.11 (1.16, 3.83; p = 0.02), 10.89 (2.44, 48.59; p = 0.002) and 0.30 (0.17, 0.53; p = 2 × 10⁻⁵) for one standard deviation increment of serum iron, transferrin saturation, ferritin and transferrin levels, respectively. For brain cancer, the corresponding odds ratios were 0.69 (0.48, 1.00; p = 0.05), 0.75 (0.59, 0.97; p = 0.03), 0.41 (0.20, 0.88; p = 0.02) and 1.49 (1.04, 2.14; p = 0.03). Genetically high iron status was positively associated with liver cancer and inversely associated with brain cancer.

Associations between non-anaemic iron deficiency and outcomes following surgery for colorectal cancer: An exploratory study of outcomes relevant to prospective observational studies

Iron deficiency is common in colorectal cancer. Despite perioperative guidelines advocating for the correction of non-anaemic iron deficiency prior to major surgery, the impact of this pathology on postoperative outcome is unclear.

We conducted a single-centre, historical cohort study of 141 elective resections for colorectal cancer. We stratified non-anaemic patients into iron deficient and iron replete groups, and collected data on baseline characteristics, preoperative laboratory results, intraoperative events and postoperative outcomes. As this study was an exploratory work for future research, a P-value of 0.25 was considered relevant. Patients in the deficient group demonstrated lower baseline ferritin (median (interquartile range, IQR) 76 (41–141) µg/L versus 207 (140–334) µg/L, P < 0.001) and transferrin saturation (mean (standard deviation, SD) 18% (8%) versus 32% (12%), P < 0.001) than those in the replete group, and lower starting haemoglobin (mean (SD) 138 (10) g/L versus 144 (12) g/L, P = 0.01). The deficient group had increased re-admission (25% (24%) versus 4% (11%), P = 0.15) and all-cause infection (25% (24%) versus 5% (14%), P = 0.24). A decrease of two days in days alive and out of hospital at postoperative day 90 was seen in the deficient group on univariate analysis (median (IQR) 81 (75–84) versus 83 (78–84), P = 0.25). This reduced to 1.24 days in multivariate adjusted quantile regression analysis ( P = 0.22). Days alive and out of hospital at day 90, postoperative re-admission and postoperative infection may be meaningful outcome measures for future prospective observational work examining non-anaemic iron deficiency in patients undergoing major surgery for colorectal cancer.

Hospital cost associated with anemia in elective colorectal surgery: a historical cohort study

PURPOSE

Anemia is highly prevalent in the colorectal surgery population, affecting 30-70% of patients. Anemia is associated with significant morbidity and mortality; however, there is a lack of evidence on how much anemia impacts healthcare costs. This study aims to determine the hospital cost of index surgical admission, postoperative length of stay, and transfusion rate associated with preoperative anemia in elective major colorectal surgery.

METHODS

This historical cohort study included 851 adult inpatients having elective colorectal surgery at a tertiary care academic health sciences network between April 2010 and February 2016. Anemia was defined as hematocrit ≤ 39%. The primary outcome was total hospital costs standardized to 2016 CAD. Secondary outcomes were postoperative length of stay and transfusion. Multivariable regression analyses and propensity score methods were used to measure adjusted associations between anemia and outcomes.

RESULTS

Before surgery, 381/851 (45%) patients were anemic. The mean (standard deviation [SD]) cost of index admission for an elective colorectal surgery was 20,040 (23,219) CAD. Anemia was associated with an adjusted 14% relative increase in costs (95% confidence interval [CI], 6 to 23; P < 0.001). The total hospitalization cost attributable to anemia was 3,027 CAD (95% CI, 2,670 to 3,388). Hospital costs and length of stay were highly associated; anemia was associated with an 18% increase in length of stay (95% CI, 7 to 30; P < 0.001) and increased transfusion rates (risk ratio, 4.7; 95% CI, 2.71 to 8.33; P < 0.001).

CONCLUSION

Over 2,600 CAD per index surgical admission is attributable to preoperative anemia. Preoperative interventions with per patient cost of less than 2,600 CAD could be cost effective at the hospital level.

TRIAL REGISTRATION

www.clinicaltrials.gov (NCT03476707); registered 26 March, 2018.

Iron metabolism and its contribution to cancer (Review)

Iron is an essential element for biological processes. Iron homeostasis is regulated through several mechanisms, from absorption by enterocytes to recycling by macrophages and storage in hepatocytes. Iron has dual properties, which may facilitate tumor growth or cell death. Cancer cells exhibit an increased dependence on iron compared with normal cells. Macrophages potentially deliver iron to cancer cells, resulting in tumor promotion. Mitochondria utilize cellular iron to synthesize cofactors, including heme and iron sulfur clusters. The latter is composed of essential enzymes involved in DNA synthesis and repair, oxidation‑reduction reactions, and other cellular processes. However, highly increased iron concentrations result in cell death through membrane lipid peroxidation, termed ferroptosis. Ferroptosis, an emerging pathway for cancer treatment, is similar to pyroptosis, apoptosis and necroptosis. In the present review, previous studies on the physiology of iron metabolism and its role in cancer are summarized. Additionally, the significance of iron regulation, and the association between iron homeostasis and carcinogenic mechanisms are discussed.

Red blood cell transfusion and its alternatives in oncologic surgery-A critical evaluation

Although blood transfusions have been used for more than 100 years and their potential to save lives is indisputable, there is still limited data on medium- and long-term outcomes after hemotherapy. Until recently, red blood cell transfusions represented the most commonly employed treatment for cancer anemia. As transfusions have been related to worse patient outcome in oncologic surgery, preventive strategies and alternative treatment approaches in the perioperative setting are warranted. This review aims to evaluate the evidence concerning the impact of transfusion on the course of malignant diseases with a focus on oncologic surgery and to provide a bundle of measures to improve patient care. The perioperative period is pivotal in determining long-term cancer outcome. An increasingly recognized area for improvement during this highly sensitive period is the treatment of anemia for three main reasons: Firstly, anemia has been recognized as an independent predictor of poor prognosis in cancer patients. Secondly, anemia is largely undertreated. Thirdly and probably most importantly, anemia therapy relied and often still relies heavily on red blood cell (RBC) transfusions, which may be an often suboptimal stopgap treatment. Perioperative RBC transfusions should be kept to a minimum due to growing concerns regarding the associated risks, which this review tries to clarify by providing an update of recent literature. This review furthermore discusses treatments for anemia and provides best-practice approaches to improve perioperative management of oncology patients undergoing surgery.

Iron therapy as treatment of anemia: A potentially detrimental and hazardous strategy in colorectal cancer patients

In colorectal cancer patients, iron therapy, and especially intravenous iron therapy, is increasingly used to treat anemia and reduce the use of blood transfusions. However, iron has also been shown to be an essential nutrient for rapidly proliferating tissues and cells. In this respect, anemia of inflammation, characterized by limited duodenal iron uptake and sequestration of iron into the reticuloendothelial system, might be regarded as a potentially effective defense strategy of the human body against tumor growth. We therefore hypothesize that iron therapy, by supporting colorectal tumor growth and increasing the metastatic potential, may worsen tumor prognosis in colorectal cancer patients. This hypothesis is particularly supported for colorectal cancer by laboratory, epidemiological and animal studies, demonstrating the role of iron in all aspects of tumor development growth. Compared to non-malignant colon cells, tumor cells differ in the levels and activity of many iron import and export proteins, resulting in an increase in intracellular iron level and enhanced proliferation. In addition, it is demonstrated that iron is able to amplify Wnt signaling in tumors with Apc mutation, a critical mutation in the development of colorectal cancer. If our hypothesis is to be confirmed, current practice of iron administration, as treatment for anemia and as replacement of blood transfusions, can be hazardous and should be completely reconsidered.