Iron therapy for the treatment of preoperative anaemia in patients with colorectal carcinoma: a systematic review

Non-erythropoiesis-stimulating agent, non-iron therapies for the management of anaemia: protocol for a scoping review

INTRODUCTION

Preoperative anaemia is associated with poor postoperative outcomes and is the strongest predictor of allogenic blood transfusion, which contributes further to patient morbidity. Emphasis has been placed on correcting anaemia prior to surgery to mitigate these outcomes. Conflicting evidence exists regarding the benefit of currently recommended interventions. With greater understanding of iron haemostasis and erythropoiesis, novel therapies have been identified. These are at varying stages of development with some demonstrating promising results in patients with chronic kidney disease. It is not known how these agents have been studied outside this population, particularly in the perioperative context. To address this, we will conduct a scoping review of the published literature to chart the evidence.

METHODS AND ANALYSIS

The scoping review will be reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews framework. The electronic database search will include Scopus, MEDLINE (Ovid) and Excerpta Medica database (Ovid), with no language restrictions, and will include all publications since 1 January 2010. This review will have three objectives: (1) to describe the mechanisms of action for novel agents, (2) to describe the level of evidence and stage of development of novel agents in a perioperative setting, and (3) to determine the potential agents suitable for prospective controlled trials in a preoperative or postoperative patient cohort and aiming to improve patient-centred outcomes. The review process will involve two reviewers with a third reviewer resolving disagreements. Data will be extracted and organised with subsequent analysis.

ETHICS AND DISSEMINATION

This scoping review does not require research ethics approval. The results will be published in a peer-reviewed journal and inform the development of future prospective trials based on established evidence from potential therapeutic agents.

TRIAL REGISTRATION NUMBER

This protocol has been registered prospectively on the Open Science Framework registry (DOI:10.17605/OSF.IO/SM3UH, https://osf.io/sm3uh/?view_only=39876ccf7a4348dfbd566535b957a7db).Cite Now.

Laparoscopic surgery does not reduce the need for red blood cell transfusion after resection for colorectal tumour: a propensity score match study on 728 patients

BACKGROUND

Patients with colorectal tumour often present with anaemia, and up to 60% will receive red blood cells (RBC) transfusion. Some evidence suggests a correlation between RBC transfusion and worse outcomes. Since laparoscopy minimizes intraoperative blood loss, we retrospectively investigated its role in reducing haemoglobin (Hb) drop and requirements for postoperative RBC transfusions.

METHODS

Patients were identified from consecutive cases undergone elective surgery for non-metastatic colorectal tumour between 2005 and 2019. Laparoscopic cases were matched 1:1 with open controls through propensity score matching (PSM). The main outcome measures were postoperative Hb drop and requirement for RBC. The secondary aim was evaluation of risk factors for postoperative RBC transfusions.

RESULTS

After application of PSM, 364 patients treated by laparoscopy were matched with 364 patients undergone open surgery. The two groups presented similar clinical and pathological characteristics, as well as comparable postoperative outcomes. 56 patients in the open group and 47 in the laparoscopic group required postoperative RBC (P = 0.395). No difference was observed in terms of mean number of RBC units (P = 0.608) or Hb drop (P = 0.129). Logistic regression analysis identified preoperative anaemia and occurrence of postoperative complications as relevant risk factors for postoperative RBC transfusion, while surgical approach did not prove statistically significant.

CONCLUSION

Laparoscopy did not influence postoperative requirements for RBC transfusions after elective colorectal surgery. Preoperative anaemia and occurrence of postoperative complications represent the major determinants for postoperative transfusions after open as well as laparoscopic surgery.

Evaluation of clinical prognostic variables on short-term outcome for colorectal cancer surgery: An overview and minimum dataset

INTRODUCTION

Surgery for colorectal cancer is associated with post-operative morbidity and mortality. Multiple systematic reviews have reported on individual factors affecting short-term outcome following surgical resection. This umbrella review aims to synthesize the available evidence on host and other factors associated with short-term post-operative complications.

METHODS

A comprehensive search identified systematic reviews reporting on short-term outcomes following colorectal cancer surgery using PubMed, Cochrane Database of Systematic Reviews and Web of Science from inception to 8th September 2020. All reported clinicopathological variables were extracted from published systematic reviews.

RESULTS

The present overview identified multiple validated factors affecting short-term outcomes in patients undergoing colorectal cancer resection. In particular, factors consistently associated with post-operative outcome differed with the type of complication; infective, non-infective or mortality. A minimum dataset was identified for future studies and included pre-operative age, sex, diabetes status, body mass index, body composition (sarcopenia, visceral obesity) and functional status (ASA, frailty). A recommended dataset included antibiotic prophylaxis, iron therapy, blood transfusion, erythropoietin, steroid use, enhance recovery programme and finally potential dataset included measures of the systemic inflammatory response CONCLUSION: A minimum dataset of mandatory, recommended, and potential baseline variables to be included in studies of patients undergoing colorectal cancer resection is proposed. This will maximise the benefit of such study datasets.

Preoperative anemia is a risk factor for poor perioperative outcomes in ventral hernia repair

PURPOSE

Ventral hernia repairs (VHR) are among the most commonly performed operations by general surgeons. Despite advances in technology there remains high complication and readmission rates. Preoperative anemia has been linked to poor outcomes and readmission across several surgical procedures, however the link to ventral hernia repair outcomes is limited.

METHODS

Utilizing the American College of Surgeons National Safety and Quality Improvement Project (NSQIP) database for years 2016-2018, a total of 115,000 patients met inclusion criteria. Using propensity matching we matched two groups of patients who underwent VHR: (1) those with preoperative anemia and (2) those with normal hemoglobin levels. Anemia criteria was set forth by the World Health Organization (WHO).

RESULTS

Univariate analysis did demonstrate statistical significance in post-operative outcomes percentage of serious surgical site infection, poor renal outcomes, transfusion, and unplanned remission in those with preoperative anemia who underwent VHR. In a multivariate analysis, patients who underwent ventral hernia repair with pre-operative anemia had significantly greater odds of unplanned readmission (odds ratio 1.35, 95% confidence interval 1.16-1.57) and serious surgical site infection (odds ratio 1.35, 95% confidence interval 1.04-1.74) independent of known risk factors such as smoking, diabetes and obesity.

CONCLUSIONS

Preoperative anemia is a risk factor for poor postoperative outcomes in those undergoing ventral hernia repair and should be considered when evaluating a patient for repair.

Iron Supplementation Effectively Ameliorates Anemia and Reduces the Need for Blood Transfusion in Patients Undergoing Colorectal Cancer Surgery: A Meta-Analysis

OBJECTIVE

Anemia is common and harmful in patients undergoing colorectal cancer (CRC) surgery. Blood transfusion (BT) is used to treat anemia, but results in a poor oncology prognosis. Iron supplementation may be effective in improving anemia and reducing the need for BT, however, the results remain controversial. This meta-analysis was conducted to evaluate the efficacy of iron supplementation in improving hemoglobin concentrations (Hb) and reducing the need for BT.

METHODS

Up to February 10, 2021, PubMed, Web of Science, Cochrane Library, Embase databases were searched for studies evaluating the effects of iron supplementation on CRC surgery patients. Meta-analysis was conduct using the random-effects model.

RESULTS

Seven trials with 879 participants in total were included in the meta-analysis. The pooled findings suggested that iron supplementation effectively increased Hb (MD 0.41; 95% CI: 0.12, 0.69, P = 0.006) and reduced the risk of BT (RR 0.60, 95% CI 0.45, 0.78, P = 0.0002) compared with the control group. In addition, subgroup analyses showed that these benefits were observed with both oral and intravenous iron supplementation.

CONCLUSION

Iron supplementation is effective in ameliorating anemia and reducing the need for BT in CRC surgery patients.

The dynamic effects of preoperative intravenous iron in anaemic patients undergoing surgery for colorectal cancer

AIM

The aim of this study was to describe the dynamic changes in blood work following individual adjusted dosage of intravenously administered iron(III) isomaltoside in a 4-week period prior to surgery in patients with colorectal cancer.

METHODS

This was a single-centre, observational cohort study with prospectively collected data, including patients with colorectal cancer receiving preoperative treatment with iron(III) isomaltoside. Blood samples were taken at baseline, 1 week, 2 weeks and 4 weeks after initial treatment. Sixty-two patients were included in the study.

RESULTS

Sixty-two patients were included for final analysis. The mean increase in haemoglobin was 0.77 g/dl (95% CI 0.52-1.03 g/dl, P < 0.0001) at week 1, 1.5 g/dl (95% CI 1.21-1.80 g/dl, P < 0.0001) at week 2 and 2.13 g/dl (95% CI 1.71-2.55 g/dl, P < 0.0001) at week 4. Patients with severe anaemia (<9.02 g/dl) showed the largest increase in haemoglobin during the treatment course (2.92 g/dl, 95% CI 2.27-3.58 g/dl, P < 0.0001). Patients with mild anaemia (>10.31 g/dl) did not show a significant increase (0.66 g/dl, 95% CI -0.29-1.61 g/dl, P = 0.17). The mean of transferrin saturation after 4 weeks was 8% (95% CI 6%-10%, P < 0.0001).

CONCLUSIONS

After intravenously administered iron, patients with severe anaemia had the most substantial increase in haemoglobin, and the increase was largest after 4 weeks. Patients with mild anaemia did not have an increase in haemoglobin during the treatment course. The vast majority of patients still had iron deficiency at surgery 4 weeks after the initial treatment.

Efficacy of Different Interventions to Reduce Pre- or Perioperative Blood Transfusion Rate in Patients with Colorectal Cancer: A Network Meta-Analysis of Randomized Controlled Trials

Background: The high proportion of blood transfusions before and during surgery carries unnecessary risk and results in poor prognosis in colorectal cancer patients. Different pharmacological interventions (i.e., iron supplement or recombinant erythropoietin) to reduce blood transfusion rates have shown inconclusive results. Methods: This network meta-analysis (NMA) consisted of randomized controlled trials (RCTs) comparing the efficacy of different pharmacologic interventions (i.e., iron supplementation or recombinant erythropoietin) to reduce the blood transfusion rate. NMA statistics were conducted using the frequentist model. Results: Seven RCTs (688 participants) were included in this study. The NMA demonstrated that the combination of high-dose recombinant human erythropoietin and oral iron supplements was associated with the least probability of receiving a blood transfusion [odds ratio = 0.24, 95% confidence intervals (95% CIs): 0.08 to 0.73] and best reduced the amount of blood transfused if blood transfusion was necessary (mean difference = −2.62 U, 95% CI: −3.55 to −1.70 U) when compared to the placebo/control group. None of the investigated interventions were associated with any significantly different dropout rate compared to the placebo/control group. Conclusions: The combination of high-dose recombinant human erythropoietin and oral iron supplements might be considered as a choice for reducing the rate of blood transfusion in patients with colorectal cancer. However, future large-scale RCT with long-term follow-up should be warranted to approve the long-term safety.

Flipside of the Coin: Iron Deficiency and Colorectal Cancer

Iron deficiency, with or without anemia, is the most frequent hematological manifestation in individuals with cancer, and is especially common in patients with colorectal cancer. Iron is a vital micronutrient that plays an essential role in many biological functions, in the context of which it has been found to be intimately linked to cancer biology. To date, however, whereas a large number of studies have comprehensively investigated and reviewed the effects of excess iron on cancer initiation and progression, potential interrelations of iron deficiency with cancer have been largely neglected and are not well-defined. Emerging evidence indicates that reduced iron intake and low systemic iron levels are associated with the pathogenesis of colorectal cancer, suggesting that optimal iron intake must be carefully balanced to avoid both iron deficiency and iron excess. Since iron is vital in the maintenance of immunological functions, insufficient iron availability may enhance oncogenicity by impairing immunosurveillance for neoplastic changes and potentially altering the tumor immune microenvironment. Data from clinical studies support these concepts, showing that iron deficiency is associated with inferior outcomes and reduced response to therapy in patients with colorectal cancer. Here, we elucidate cancer-related effects of iron deficiency, examine preclinical and clinical evidence of its role in tumorigenesis, cancer progression and treatment response. and highlight the importance of adequate iron supplementation to limit these outcomes.

Role of preoperative erythropoietin in the optimization of preoperative anemia among surgical patients - A systematic review and meta-analysis

Preoperative anemia is a common finding. Preoperative allogeneic transfusion, iron therapy, vitamin supplementation and erythropoietin therapy are the current management strategies for preoperative anemia. Previous reviews regarding erythropoietin were limited to specialties, provided little evidence regarding the benefits and risks of erythropoietin in managing preoperative anemia and included non-anemic patients. The purpose of our systematic review was to determine the role of erythropoietin solely in preoperatively anemic patients and to investigate the complications of this treatment modality to produce a guideline for preoperative management of anemic patients for all surgical specialties. The PubMed/Medline, Google Scholar, and Cochrane Library were searched for randomized trials evaluating the efficacy of erythropoietin in preoperative anemia. The risk ratio (RR) and standardized mean difference (SMD) was used to pool the estimates of categorical and continuous outcomes, respectively. Allogeneic transfusion and complications and the 90-day mortality were the primary outcomes, while the postoperative change in hemoglobin, bleeding in milliliters and the number of red blood cell (RBC) packs transfused were the secondary outcomes. Results: Eight studies were included, comprising 734 and 716 patients in the erythropoietin group and non-erythropoietin group, respectively. The pooled estimate by RR for allogeneic transfusion was 0.829 (p = 0.049), while complications and the 90-day mortality were among the 1,318 (p = 0.18) patients. Conclusion: Preoperative erythropoietin provides better outcomes, considering the optimization of preoperative anemia for elective surgical procedures. The benefits of erythropoietin are significantly higher, compared to the control group, while the risks remain equivocal in both groups. We recommend preoperative erythropoietin in anemic patients.

Anaesthesia as an influence in tumour progression

Purpose

Tumour growth and the formation of metastases are essential elements in the progression of cancer. The centre of treatment is the surgical resection of primary solid tumours. But even if the tumour can be removed without microscopic residual cells, local recurrences and distant metastases occur and determine the patient’s fate. During the operation, tumour cells are shed from the primary tumour and released into the circulation. These circulating tumour cells might play an important role in the formation of new tumour sites. Therefore, a functional innate and adaptive immune system is essential, especially in this perioperative period. Anaesthesia influences consciousness and pain perception and interacts directly with the immune system and tumour cells.

Methods

Review of the current literature concerning intra- and postoperative anaesthetic decisions and tumour progression.

Results

There are beneficial aspects for patient survival associated with total intravenous anaesthesia, the use of regional anaesthetics and the avoidance of allogeneic red blood cell transfusions. Alternatives such as irradiated intraoperative blood salvage and preoperative iron supplementation may be advantageous in cases where transfusions are limited or not wanted. The immunosuppressive properties of opioids are theoretical, but strong evidence to avoid them does not exist. The application of nonsteroidal anti-inflammatory drugs and postoperative nausea and vomiting prophylaxis do not impair the patient’s survival and may even have a positive effect on tumour regression.

Conclusion

Anaesthesia does play an important part in the perioperative period in order to improve the cancer-related outcome. Further research is necessary to make more concrete recommendations.

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.

[Diagnostics and treatment of preoperative anemia]

Approximately 14-40% of patients in industrialized countries present with preoperative anemia. Depending on the severity, anemia is associates with increased perioperative morbidity and mortality. One of the most important causes of preoperative anemia is iron deficiency which is usually easy to treat. Implemented in the multimodal concept of patient blood management, the diagnostics and treatment of preoperative anemia are important aspects for improvement of perioperative outcome. Adequate and early diagnostics of the cause of anemia before treatment is important because treatment options, e.g. with iron, erythropoetin, folic acid and vitamin B₁₂, may be expensive, may have severe side effects, and in the case of a wrong indication, will not improve anemia. In addition, an adequate regeneration of the erythrocyte volume requires time. This review article presents important aspects of the epidemiology and prognostic implications of preoperative anemia, the physiology and pathophysiology of anemia as well as diagnostic features and the evidence base for preoperative treatment options.

Intravenous iron versus oral iron or observation for gastrointestinal malignancies: a systematic review

BACKGROUND

Anemia is a common condition in patients with gastrointestinal cancer. Current evidence for the use of intravenous compared with oral iron in this clinical setting is inconclusive. A systematic review was performed to assess evidence on the efficacy of intravenous iron versus oral/observation in gastrointestinal cancer patients in the preoperative and postoperative setting.

MATERIALS AND METHODS

We searched Medline and Embase from inception until December 2017 with no language restrictions. Outcomes included hemoglobin response, red blood cell transfusion, and adverse events. Screening, data abstraction, and risk of bias appraisal were performed by two independent reviewers. The risk of bias was assessed using the Cochrane tools for randomized and nonrandomized studies.

RESULTS

A total of 10 studies (three randomized-controlled trials and seven nonrandomized studies) were included. Of the six preoperative studies, five reported that hemoglobin was significantly higher in the intravenous group compared with oral iron/observation. Among the four postoperative studies, three studies suggested that hemoglobin was significantly higher in the intravenous group compared with oral iron/observation. The overall risk of bias for all randomized-controlled trials was low. Quality assessments for nonrandomized studies found the risk of bias to be moderate for four studies and critical for three studies.

CONCLUSION

Despite the limitations of the current body of evidence, there is a likely benefit to the use of intravenous iron in this patient population. Further confirmatory research is needed to draw empirical conclusions.

Anemia and Iron Deficiency in Cancer Patients: Role of Iron Replacement Therapy

Anemia in cancer patients is quite common, with remarkable negative impacts on quality of life and overall prognosis. The pathogenesis is complex and typically multifactorial, with iron deficiency (ID) often being a major and potentially treatable contributor. In turn, ID in cancer patients can be due to multiple concurring mechanisms, including bleeding (e.g., in gastrointestinal cancers or after surgery), malnutrition, medications, and hepcidin-driven iron sequestration into macrophages with subsequent iron-restricted erythropoiesis. Indeed, either absolute or functional iron deficiency (AID or FID) can occur. While for absolute ID there is a general consensus regarding the laboratory definition (that is ferritin levels <100 ng/mL ± transferrin saturation (TSAT) <20%), a shared definition of functional ID is still lacking. Current therapeutic options in cancer anemia include iron replacement, erythropoietic stimulating agents (ESAs), and blood transfusions. The latter should be kept to a minimum, because of concerns regarding risks, costs, and limited resources. Iron therapy has proved to be a valid approach to enhance efficacy of ESAs and to reduce transfusion need. Available guidelines focus mainly on patients with chemotherapy-associated anemia, and generally suggest intravenous (IV) iron when AID or FID is present. However, in the case of FID, the upper limit of ferritin in association with TSAT <20% at which iron should be prescribed is a matter of controversy, ranging up to 800 ng/mL. An increasingly recognized indication to IV iron in cancer patients is represented by preoperative anemia in elective oncologic surgery. In this setting, the primary goal of treatment is to decrease the need of blood transfusions in the perioperative period, rather than improving anemia-related symptoms as in chemotherapy-associated anemia. Protocols are mainly based on experiences of Patient Blood Management (PBM) in non-oncologic surgery, but no specific guidelines are available for oncologic surgery. Here we discuss some possible approaches to the management of ID in cancer patients in different clinical settings, based on current guidelines and recommendations, emphasizing the need for further research in the field.

Impact of Preoperative Anemia on Perioperative Outcomes in Patients Undergoing Elective Colorectal Surgery

Aim

To evaluate the impact of preoperative anemia (POA) on perioperative outcomes in patients undergoing elective surgery for colorectal cancer (CRC).

Methods

A total of 326 CRC patients were enrolled. POA was defined as a hemoglobin (Hb) concentration ≤ 12 g/dl. Univariable and multivariable analyses were performed to assess the impact of POA on the risks of postoperative complications like surgical site infection (SSI).

Results

Patients with colon cancer presented higher rate of POA than patients with rectal cancer (60% versus 40% for colon cancer versus rectal cancer). In addition, female patients and patients with large tumor mass (>4 cm) had a higher rate of POA than male patients and patients with small tumor (≤4 cm), respectively. Upon univariable analysis, CRC patients with POA had a higher rate of incisional SSI than patients without POA (12% versus 6%, P = 0.04). However, POA was not associated with other postoperative complications, like anastomotic leak, organ space SSI, and bleeding. Upon multivariable analysis, POA and stoma formation were identified as two independent risk factors for incisional SSI (OR (95%CI): 2.44 (1.09–5.49) for POA versus no POA and 2.64 (1.20–5.81) for stoma formation versus no stoma formation).

Conclusions

POA was an independent risk factor for incisional surgical site infection after colorectal resection for CRC, and correcting POA should be considered before elective surgery.

Impact of ferric carboxymaltose on the evolution of hemoglobin and ECOG performance status in iron-deficient patients with solid tumors: a 3-month follow-up retrospective study

BACKGROUND

Anemia is often associated with a lower quality of life and less tolerance to treatments in cancer patients.

OBJECTIVE

The aims of this retrospective study were to assess the biological (hemoglobin, Hb) and clinical (ECOG index) impact of ferric carboxymaltose (FCM) and to identify predictive factors of response in cancer patients with iron deficiency.

METHODS

We included 133 patients with solid tumors who received at least one dose of FCM in 2015.

RESULTS

At baseline, most patients had metastatic cancer (70%), were undergoing chemotherapy (82%), suffered from anemia (90%), and 72% had an ECOG 0-1 index. Mean Hb level was statistically higher at M1 (108.3 g/L ± 13.9), M2 (110.3 g/L ± 16.1), and M3 (111.7 g/L ± 12.6) than M0 (99.2 g/L ± 13.9). Mean ECOG score increased significantly at M1 (1.31 ± 0.80) and M2 (1.31 ± 0.87) compared to M0 (1.13 ± 0.80). Variations of ECOG index between M0 and M1 were independent of levels of Hb and ferritin at inclusion and pretreatment use of transfusion and ESAs. Increase of Hb level was higher in patients with Hb < 100 g/L, ferritinemia < 800 ng/ml, or transfused before inclusion. In multivariate analysis, an ECOG index of 0 was the only predictive factor of an increase of ECOG index and Hb level < 100 g/L and ferritinemia < 800 ng/ml were predictive of an increase in Hb.

CONCLUSION

Even though there was no improvement in ECOG index, this study did identify an increase of Hb for patients receiving FCM, indicating its potential benefit in iron-deficient cancer patients.

Preoperative anemia in colorectal cancer: relationships with tumor characteristics, systemic inflammation, and survival

Anemia is common in colorectal cancer (CRC) but its relationships with tumor characteristics, systemic inflammation, and survival have not been well characterized. In this study, blood hemoglobin levels and erythrocyte mean corpuscular volume (MCV) levels were measured in two independent cohorts of 148 CRC patients and 208 CRC patients, and their correlation with patient and tumor characteristics, systemic inflammatory markers (modified Glasgow Prognostic Score: mGPS; serum levels of thirteen cytokines, C-reactive protein, albumin), and survival were analyzed. We found that anemia, most frequently normocytic, followed by microcytic, was present in 43% of the patients. Microcytic anemia was most commonly associated with proximal colon tumor location. Average MCV and blood hemoglobin levels were lower in tumors with high T-class. Low blood hemoglobin associated with systemic inflammation, including high mGPS and high serum levels of C-reactive protein and IL-8. Particularly, normocytic anemia associated with higher mGPS. Normocytic anemia associated with a tendency towards worse overall survival (multivariate hazard ratio 1.61, 95% confidence interval 1.07–2.42, p = 0.023; borderline statistical significance considering multiple hypothesis testing). In conclusion, anemia in CRC patients is most frequently normocytic. Proximal tumor location is associated with predominantly microcytic anemia and systemic inflammation is associated with normocytic anemia.

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.

Long-term prognostic value of preoperative anemia in patients with colorectal cancer: A systematic review and meta-analysis

OBJECTIVE

To evaluate the long-term prognostic factor of preoperative anemia in colorectal cancer patients.

BACKGROUND

Anemia is frequently observed in colorectal cancer patients, with a case incidence of 30 to 67 percent. Besides an indicator of tumor-induced blood loss and inflammation, anemia in cancer is also suggested to be a cause of inferior outcome, possibly via worsening of tumor hypoxia. As surgery is likely to enhance anemia, the long-term prognostic value of preoperative anemia seems most interesting.

METHODS

Comprehensive searches were carried out in all relevant databases, including MEDLINE, Embase and Web-of-Science. To include studies addressing overall survival, follow-up had to be at least 24 months or till death. For pooling of survival results, a mixed-linear (fixed-effects) model was fit to the reported hazard ratios (HRs) to calculate a pooled estimate and confidence interval.

RESULTS

We included 12 studies comprising 3588 patients to estimate the association between preoperative anemia and overall survival (OS) and disease-free survival (DFS). In a fixed-effects meta-analysis of eight studies, including both colon and rectal cancer, preoperative anemia was significantly associated with poor OS (HR 1.56; 95% CI 1.30 to 1.88; p < 0.001). A meta-analysis of seven studies also showed that preoperative anemia was significantly associated with poor DFS (HR 1.34; 95% CI 1.11 to 1.61; p = 0.002). Restricted to studies exclusively on colon cancer or rectal cancer, HRs for OS were 1.25 (95% CI 1.00 to 1.55; p = 0.05) and 2.59 (95% CI 1.68 to 4.01; p < 0.001), respectively, while HRs for DFS were 1.21 (95% CI 0.96 to 1.52; p = 0.11) and 1.61 (95% CI 1.18 to 2.21; p = 0.003).

CONCLUSION

The present meta-analysis reveals that preoperative anemia is significantly associated with decreased long-term OS and DFS in rectal cancer, but not in colon cancer patients, although this meta-analysis is mainly based on retrospective studies with high heterogeneity. These results justify raised awareness about the impact of preoperative anemia on long-term survival.

Randomized clinical trial of preoperative oral versus intravenous iron in anaemic patients with colorectal cancer

BACKGROUND

Treatment of preoperative anaemia is recommended as part of patient blood management, aiming to minimize perioperative allogeneic red blood cell transfusion. No clear evidence exists outlining which treatment modality should be used in patients with colorectal cancer. The study aimed to compare the efficacy of preoperative intravenous and oral iron in reducing blood transfusion use in anaemic patients undergoing elective colorectal cancer surgery.

METHODS

Anaemic patients with non-metastatic colorectal adenocarcinoma were recruited at least 2 weeks before surgery and randomized to receive oral (ferrous sulphate) or intravenous (ferric carboxymaltose) iron. Perioperative changes in haemoglobin, ferritin, transferrin saturation and blood transfusion use were recorded until postoperative outpatient review.

RESULTS

Some 116 patients were included in the study. There was no difference in blood transfusion use from recruitment to trial completion in terms of either volume of blood administered (P = 0·841) or number of patients transfused (P = 0·470). Despite this, increases in haemoglobin after treatment were higher with intravenous iron (median 1·55 (i.q.r. 0·93-2·58) versus 0·50 (-0·13 to 1·33) g/dl; P < 0·001), which was associated with fewer anaemic patients at the time of surgery (75 versus 90 per cent; P = 0·048). Haemoglobin levels were thus higher at surgery after treatment with intravenous than with oral iron (mean 11·9 (95 per cent c.i. 11·5 to 12·3) versus 11·0 (10·6 to 11·4) g/dl respectively; P = 0·002), as were ferritin (P < 0·001) and transferrin saturation (P < 0·001) levels.

CONCLUSION

Intravenous iron did not reduce the blood transfusion requirement but was more effective than oral iron at treating preoperative anaemia and iron deficiency in patients undergoing colorectal cancer surgery.

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

BACKGROUND

In preoperative blood management of colorectal cancer patients, intravenous iron therapy is increasingly used to treat anaemia and prevent red blood cell transfusions. However, while iron deficiency is the most common cause of anaemia, little is known about the prevalence and namely type of iron deficiency in this population, whereas both types of iron deficiency (i.e. absolute and functional iron deficiency) are recommended to be treated differently by international cancer guidelines.

OBJECTIVE

The aim of present study is to investigate the prevalence and namely type of iron deficiency in colorectal cancer patients, and to assess its clinical relevance.

METHODS

Preoperative iron status, clinical parameters (i.e. age, ASA classification, tumour location, tumour stage) and postoperative complications were retrospectively collected for all newly diagnosed colorectal cancer patients in our institution over a 3-year period.

RESULTS

Iron deficiency was observed in 163 (48.1%) of 339 patients. Of these iron-deficient patients, 3.7% had an isolated absolute iron deficiency (AID) and 15.3% a functional iron deficiency (FID), while the rest had a combination of AID and FID. Anaemia was present in 66.1% of iron-deficient patients. Iron deficiency was significantly associated with an increased postoperative complication rate (univariable OR 1.94, p = 0.03, multivariable OR 1.84, p = 0.07), with right-sided tumours (p < 0.001), high ASA classification (p = 0.002), advanced tumour stage (p = 0.01) and advanced age (p = 0.04). In comparing clinical parameters between patients with AID and FID, advanced age was significantly associated with FID (p = 0.03), and the presence of anaemia with AID (p = 0.02).

CONCLUSION

In preoperative colorectal cancer patients, there is a high prevalence of iron deficiency, including a high percentage of patients with-a component of-functional iron deficiency, associated with the increased postoperative complication rate. As both types of iron deficiency require a different treatment strategy, our results illustrate the therapeutic potential of especially intravenous iron supplementation in patients with severe iron deficiency and stress the urgency of routinely monitoring preoperative iron status and differentiation between types of iron deficiency. As iron therapy may also be potentially harmful in respect to stimulation of tumour growth, future clinical trials assessing the long-term effect of iron therapy are necessary.