Is Autologous Salvaged Blood a Viable Option for Patient Blood Management in Oncologic Surgery?

Consensus of the Brazilian association of hematology, hemotherapy and cellular therapy on patient blood management: Acute normovolemic hemodilution and intraoperative autotransfusion

Autologous blood transfusion can be achieved through different techniques, including by the patient donating blood before surgery (pre-deposit), collecting blood from the patient immediately before the operation and replacing the volume with colloids or plasma expanders (acute normovolemic hemodilution) or through the salvage of lost blood, during or immediately after surgery, and its retransfusion after washing (intraoperative or postoperative recovery). We will focus on the two methods used intraoperatively that are of fundamental importance in the management and conservation of the patient's own blood.

Current role of intraoperative cell salvage techniques in the management of renal tumors with level III and IV inferior vena cava thrombus extension

Background

En bloc removal of the kidney with tumor thrombus excision in a multidisciplinary team remains the standard treatment for renal cell carcinoma (RCC) with tumor thrombus extension. In order to minimize the hemodynamic impact of the surgical blood loss, intraoperative cell salvage (IOCS) techniques can decrease the need for allogeneic blood and prevent blood transfusion related complications.

Objective

In this article, we evaluated the safety of IOCS during radical nephrectomy with inferior vena cava thrombectomy under cardiopulmonary bypass with or without deep hypothermic circulatory arrest.

Design and method

In this retrospective comparative multicenter analysis, clinical characteristics of 27 consecutive patients who underwent surgery with or without IOCS between 2012 and 2022 in three referral care units were collected into a database. The need for an allogenic blood transfusion (ABT) was also recorded, defined as any transfusion that occurred either intraoperatively or during the hospital stay.

Results

The need for ABT in the cell saver arm was significantly smaller due to the reinfusion of rescued blood (p < 0.015). In multivariate analysis, no cell saver usage was an independent predictor for complications ⩾3 Clavien 3a [odds ratio (OR) 18.71, 95% CI 1.056-331.703, p = 0.046]. No usage of IOCS was an independent predictor for a lower risk of death (OR 0.277, 95% CI 0.062-0.825, p = 0.024). During follow-up, patients who received salvaged blood did not experience an increased risk for developing local recurrence or distant metastases.

Conclusion

Transfusion of autologous blood is safe and can be using during nephrectomy and thrombectomy for advanced RCC.

Intraoperative cell-salvaged autologous blood transfusion is safe in metastatic spine tumour surgery: early outcomes of prospective clinical study

PURPOSE

Allogeneic blood transfusion (ABT) is current standard of blood replenishment despite known complications. Salvaged blood transfusion (SBT) addresses majority of such complications. Surgeons remain reluctant to employ SBT in metastatic spine tumour surgery (MSTS), despite ample laboratory evidence. This prompted us to conduct a prospective clinical study to ascertain safety of intraoperative cell salvage (IOCS), in MSTS.

METHODS

Our prospective study included 73 patients who underwent MSTS from 2014 to 2017. Demographics, tumour histology and burden, clinical findings, modified Tokuhashi score, operative and blood transfusion (BT) details were recorded. Patients were divided based on BT type: no blood transfusion (NBT) and SBT/ABT. Primary outcomes assessed were overall survival (OS), and tumour progression was evaluated using RECIST (v1.1) employing follow-up radiological investigations at 6, 12 and 24 months, classifying patients with non-progressive and progressive disease.

RESULTS

Seventy-three patients [39:34(M/F)] had mean age of 61 years. Overall median follow-up and survival were 26 and 12 months, respectively. All three groups were comparable for demographics and tumour characteristics. Overall median blood loss was 500 mL, and BT was 1000 mL. Twenty-six (35.6%) patients received SBT, 27 (37.0%) ABT and 20 (27.4%) NBT. Females had lower OS and higher risk of tumour progression. SBT had better OS and reduced risk of tumour progression than ABT group. Total blood loss was not associated with tumour progression. Infective complications other than SSI were significantly (p = 0.027) higher in ABT than NBT/SBT groups.

CONCLUSIONS

Patients of SBT had OS and tumour progression better than ABT/NBT groups. This is the first prospective study to report of SBT in comparison with control groups in MSTS.

Contemporary practice and perception of autologous blood salvage in hepato-pancreatico-biliary operations: an international survey

BACKGROUND

This study aimed to assess contemporary knowledge, attitudes and behaviors around transfusion of intraoperative salvaged blood (sRBCt) during hepato-pancreatico-biliary (HPB) operations. Findings are meant to inform the design of future studies that address provider concerns to change behaviors and improve patient outcomes.

METHODS

A survey was designed and assessed for relevance, readability and content, and distributed to an international audience of surgeons performing HPB operations.

RESULTS

The 237 respondents were predominantly distributed across North America (37.55%), Europe (27.43%) and Asia (19.83%). Roughly one-half (52.74%) of respondents had used sRBCt in HPB surgery before. Transplantation surgeons were more likely than HPB surgeons to have previously used sRBCt [odds ratio = 5.18 (95% CI 1.89-14.20)]. More respondents believed sRBCt was safe for non-cancer versus cancer operations (68.57% vs. 24.17%, p < 0.0001). Less than half (45.71%) of respondents believed that sRBCt was safe in clean-contaminated fields. Most did not utilize preoperative strategies to avoid donor transfusion.

CONCLUSION

Practices related to sRBCt in HPB operations vary widely and there is no consensus on its use. Concerns seem primarily related to cancer-specific and infectious outcomes. While further studies are pursued, surgeons may increase their utilization of preoperative strategies to boost hemoglobin levels for at risk patients.

Perioperative blood pressure and heart rate alterations after carotid body tumor excision: a retrospective study of 108 cases

BACKGROUND

Arising from chemoreceptor cells, carotid body tumors (CBTs) are rare neoplasms associated with hemodynamics. Perioperative changes in blood pressure (BP) and heart rate (HR) are not completely understood.

METHODS

This retrospective, observational, controlled study included all CBT patients from 2013 to 2018 in Peking Union Medical College Hospital. Perioperative changes in BP/HR within or between unilateral/bilateral/control groups were investigated. Perioperative details across Shamblin types were also assessed.

RESULTS

This study included 108 patients (116 excised CBTs). The postoperative systolic BP and HR increased in both unilateral (mean difference of systolic BP = 5.9mmHg, 95% CI 3.1 ~ 8.6; mean difference of HR = 3.7 bpm, 95% CI 2.6 ~ 4.9) and bilateral (mean difference of systolic BP = 10.3mmHg, 95% CI 0.6 ~ 19.9; mean difference of HR = 8.4 bpm, 95% CI 0.5 ~ 16.2) CBT patients compared with the preoperative measures. Compared with control group, the postoperative systolic BP increased (difference in the alteration = 6.3mmHg, 95% CI 3.5 ~ 9.0) in unilateral CBT patients; both systolic BP (difference in the alteration = 9.2mmHg, 95% CI 1.1 ~ 17.3) and HR (difference in the alteration = 5.3 bpm, 95% CI 1.0 ~ 9.6) increased in bilateral CBT patients. More CBT patients required extra antihypertensive therapy after surgery than controls (OR = 2.5, 95% CI 1.14 ~ 5.5). Maximum tumor diameter, intraoperative vascular injury, continuous vasoactive agent requirement, total fluid volume, transfusion, estimated blood loss, operation duration, postoperative pathology, overall complications, and intensive care unit/hospital lengths of stay significantly varied among Shamblin types.

CONCLUSION

CBT excision may be associated with subtle perioperative hemodynamic changes. Perioperative management of CBT patients necessitates careful assessment, full preparation and close postoperative monitoring.

Cell Salvage in Oncological Surgery, Peripartum Haemorrhage and Trauma

Oncological surgery, obstetric haemorrhage and severe trauma are the most challenging conditions for establishing clinical recommendations for the use of cell salvage. When the likelihood of allogeneic transfusion is high, the intraoperative use of this blood-saving technique would be justified, but specific patient selection criteria are needed. The main concerns in the case of oncological surgery are the reinfusion of tumour cells, thereby increasing the risk of metastasis. This threat could be minimized, which may help to rationalize its indication. In severe peripartum haemorrhage, cell salvage has not proven cost-effective, damage control techniques have been developed, and, given the risk of fetomaternal alloimmunization and amniotic fluid embolism, it is increasingly out of use. In trauma, bleeding may originate from multiple sites, coagulopathy may develop, and it should be evaluated whether re-transfusion of autologous blood collected from uncontaminated organ cavities would be feasible. General safety measures include washing recovered blood and its passage through leukocyte depletion filters. To date, no well-defined indications for cell salvage have been established for these pathologies, but with accurate case selection and selective implementation, it could become safe and effective. Randomized clinical trials are urgently needed.

Safety and feasibility of urological procedures in Jehovah's Witness patients

OBJECTIVES

To describe the safety and feasibility of urological transfusion-free surgeries in Jehovah's Witness patients.

METHODS

An institutional review board-approved, retrospective review of Jehovah's Witness patients who underwent urological transfusion-free surgeries between 2003 and 2019 was carried out. Surgeries were stratified into low, intermediate and high risk based on complexity, invasiveness and bleeding potential. Patient demographics, perioperative data and clinical outcomes are reported.

RESULTS

A total of 161 Jehovah's Witness patients (median age 63.4 years) underwent 171 transfusion-free surgeries, including 57 (33.3%) in low-, 82 (47.9%) in intermediate- and 32 (18.8%) in high-risk categories. The mean estimated blood loss increased with risk category at 48 mL (range 10-50 mL), 150 mL (range 50-200 mL) and 388 mL (range 137-500 mL), respectively (P < 0.001). Implementing blood augmentation and conservation techniques increased with each risk category (3.5% vs 29% vs 69%, respectively; P < 0.001). Average length of stay increased concordantly at 1.6 days (range 0-12 days), 2.9 days (range 1-13 days) and 5.6 days (range 2-12 days), respectively (P ≤ 0.001). However, there was no increase in complication rates and readmission rates attributed to bleeding among the risk categories at 30 days (P = 0.9 and 0.4, respectively) and 90 days (P = 0.7 and 0.7, respectively).

CONCLUSIONS

Transfusion free urological surgery can be safely carried out on Jehovah's Witness patients using contemporary perioperative optimization. Additionally, these techniques can be expanded for use in the general patient population to avoid short- and long-term consequences of perioperative blood transfusion.

Preoperative Management of a Jehovah's Witness Patient Undergoing Head and Neck Surgery With High Risk of Bleeding

ABSTRACT

Surgery in head and neck district is often associated with bleeding as major complication and need of blood transfusions. Homologous blood transfusions may be unacceptable to some patient groups such as the Jehovah's Witness (JW) patients. Refusal of potentially life-saving treatment creates ethical dilemmas for treating clinicians.This is the first report in literature which examines the management and treatment of a female JW patient who underwent major surgical procedure for squamous cell carcinoma of the jaw with a high risk of hemorrage which rejected any possibility of blood and hemocomponent transfusion by virtue of her religious principles.

[Safety of cell salvage in tumor surgery : Systematic review with meta-analysis]

BACKGROUND

Allogeneic blood transfusion is avoidable in many oncological interventions by the use of cell salvage or mechanical autotransfusion (MAT). As irradiation is elaborate and expensive, the safety of leucocyte depletion filters (LDF) for autologous blood from the surgical field might be a more acceptable alternative for the prevention of cancer recurrences. A previous meta-analysis could not identify an increased risk of cancer recurrence. The aim of this review article is to provide an update of a previous meta-analysis from 2012 as well as a safety analysis of cell salvage with LDF due to the improved data situation.

MATERIAL AND METHODS

This systematic review included all studies in PubMed, Cochrane, Cochrane Reviews and Web of Science on cell salvage or autotransfusion combined with outcomes, e.g. cancer recurrence, mortality, survival, blood transfusion, length of hospital stay (LOS) after the use of MAT without irradiation and with or without LDF. The grades of recommendations (GRADE) assessment of underlying evidence was applied.

RESULTS

A total of seven new observational studies and seven meta-analyses were found that compared unfiltered or filtered cell salvage with autologous predeposition, allogeneic transfusion or without any transfusion. No randomized controlled trials have been completed. A total of 27 observational and cohort studies were included in a meta-analysis. The evidence level was low. The risk of cancer recurrence in recipients of autologous salvaged blood with or without LDF was reduced (odds ratio, OR 0.71, 95% confidence interval, CI 0.58-0.86) as compared to non-transfused subjects, allogeneic or predeposited autologous transfusion. The transfusion rate could not be assessed due to the substantial selection bias and large heterogeneity. Cell salvage does not change mortality and LOS. Leucocyte depletion studies reported a removal rate of cancer cells in the range of 99.6-99.9%.

CONCLUSION

Randomized controlled trials on a comparison of MAT and allogeneic blood transfusion as well as LDF and irradiation would be desirable but are not available. From observational trials and more than 6300 subjects and various tumors, cell salvage in cancer surgery with or without LDF appears to be sufficiently safe. The efficacy of leucocyte depletion of autologous salvaged blood is equivalent to irradiation. Unavailability of radiation is not a contraindication for cell salvage use in cancer surgery. By usage of leucocyte depleted salvaged autologous blood, the risks of allogeneic transfusion can be avoided.

Perioperative Management of Complex Hepatectomy for Colorectal Liver Metastases: The Alliance between the Surgeon and the Anesthetist

Simple Summary

Major high-risk surgery (HRS) exposes patients to potential perioperative adverse events. Hepatic resection of colorectal metastases can surely be included into the HRS class of operations. Limiting such risks is the main target of the perioperative medicine. In this context the collaboration between the anesthetist and the surgeon and the sharing of management protocols is of utmost importance and represents the key issue for a successful outcome. In our institution, we have been adopting consolidated protocols for patients undergoing this type of surgery for decades; this made our mixed team (surgeons and anesthetists) capable of achieving a safe outcome for the majority of our surgical population. In this narrative review, we report the most recent state of the art of perioperative management of hepatic resection of colorectal metastases along with our experience in this field, trying to point out the main issues.

Abstract

Hepatic resection has been widely accepted as the first choice for the treatment of colorectal metastases. Liver surgery has been recognized as a major abdominal procedure; it exposes patients to a high risk of perioperative adverse events. Decision sharing and the multimodal approach to the patients’ management are the two key items for a safe outcome, even in such a high-risk surgery. This review aims at addressing the main perioperative issues (preoperative evaluation; general anesthesia and intraoperative fluid management and hemodynamic monitoring; intraoperative metabolism; administration policy for blood-derivative products; postoperative pain control; postoperative complications), in particular, from the anesthetist’s point of view; however, only an alliance with the surgery team may be successful in case of adverse events to accomplish a good final outcome.

How I treat anemia in the perisurgical setting

Anemia is a common finding in the perioperative setting with significant untoward consequences including worsening of outcomes and diminished quality of life as well as increased risk of allogeneic blood transfusions. Here, we present 3 cases that illustrate how anemia can be perioperatively managed in patients undergoing cardiac, orthopedic, and oncology surgeries. Timely detection of anemia prior to high-blood loss surgeries can allow clinicians to manage it and optimize hemoglobin level, making patients better prepared for the surgery. Treatment of anemia should be guided by the etiology and may include erythropoietic agents, folic acid, B12, and iron preparations. Other blood management strategies geared toward reducing surgical blood loss such as autologous transfusion techniques and agents to optimize hemostasis are used during surgery and in the immediate postoperative period. Patients should be closely monitored following surgery for signs of ongoing bleeding in need of control. Finally, screening for and management of anemia should continue in the postoperative and postdischarge period, as persistence and recurrence of anemia can further undermine patient's outcomes.

Impact of intraoperative allogenic and autologous transfusion on immune function and prognosis in patients with hepatocellular carcinoma

The effect of intraoperative blood transfusion on the immune function and prognosis of hepatocellular carcinoma (HCC) has not been fully investigated. The aim of this study was to evaluate the effects of intraoperative autologous blood transfusion and allogeneic blood transfusion on immune function and prognosis in surgically treated HCC patients. One hundred fourteen primary hepatic carcinoma patients who would undergo selective operations were divided into two groups, 35 patients in the experimental group received intraoperative autologous blood transfusion and 79 patients in the control group received allogeneic blood transfusion. The amount of serum T lymphocyte subsets, natural killer (NK) cells and immunoglobulin before and after operation, as well as the recurrence-free survival (RFS) were compared. Results shown that, there was no significant difference in the level of immunocytes and immunoglobulin between the two groups before treatment (P > .05). At 1 day after surgery, there were significant differences in T lymphocyte, NK cells and immunoglobulin levels before and after transfusion. CD3+, CD4+, CD4+/CD8+, and NK cells in autologous transfusion group were significantly higher than those in allogeneic transfusion group (P < .05); the level of IgG, IgM, and IgA in allogeneic transfusion group were significantly lower than those before operation (P < .05), the level of IgG, IgM, and IgA in autologous transfusion group did not significantly fluctuate, and significantly higher than those of allogeneic transfusion group (P < .05). At 5 days after surgery, all indexes of autologous transfusion group recovered to the preoperative level, the levels of CD3+, CD4+, CD4+/CD8+, NK cells, IgG, IgM, and IgA were significantly higher than those of allogeneic transfusion group (P < .05). The follow-up results showed that the RFS of autologous transfusion group was significantly higher than that of allogeneic transfusion group (P < .05). In conclusion, compared with allogeneic blood transfusion, intraoperative autologous blood transfusion possessed less impact on immune function, it may even improve immune function and RFS in HCC patients after surgery. Therefore, HCC patients should be recommended to receive autologous blood transfusion instead of allogeneic blood transfusion when they need blood transfusion during the perioperative period.

Major liver surgery in a Jehovah’s Witness patient: challenges for safe surgery

Jehovah’s Witnesses presenting for major surgery run the risk of major bleeding, which is complicated by the refusal to accept blood transfusion. We present a case of a 63-year-old woman, a Jehovah’s Witness, who was diagnosed with hepatocellular carcinoma and advised for curative laparoscopic liver segmentectomy. Due to the risk of significant intraoperative haemorrhage, her perioperative care was coordinated in a multidisciplinary manner. Informed consent requires the physician to advise on the material risks of undertaking major surgery without blood transfusion and the possible alternatives. Conflicting ethical issues of patient autonomy and beneficence related to refusal of blood products also arise. Perioperative strategies to minimise blood loss, maximise haematopoiesis and tolerance of anaemia to facilitate safe surgery in such patients are also presented. Written patient consent obtained.

Survival analysis of intraoperative blood salvage for patients with malignancy disease: A PRISMA-compliant systematic review and meta-analysis

BACKGROUND

Intraoperative blood salvage as a blood-saving strategy has been widely used in surgery. Considering its theoretic risk of malignant tumor cells being reinfused and the corresponding blood metastases, the safety of intraoperative blood salvage in cancer surgery remains controversial.

METHODS

Following the Preferred Reporting Items for Systemic Review and Meta-Analysis (PRISMA), we searched the Cochrane Library, MEDLINE and EMBASE to November 2017. We included only studies comparing intraoperative blood salvage with allogeneic blood transfusion.

RESULTS

This meta-analysis included 9 studies with 4354 patients with 1346 patients in the intraoperative blood salvage group and 3008 patients in the allogeneic blood transfusion group. There were no significant differences in the 5-year overall survival outcome (odds ratio [OR] 1.12; 95% confidence interval [CI], 0.80-1.58), 5-year disease-free survival outcome (OR 1.08; 95% CI 0.86-1.35), or 5-year recurrence rate (OR 0.86; 95% CI 0.71-1.05) between the 2 study groups. Subgroup analysis also showed no significant differences in the 5-year overall survival outcome (OR 0.97; 95% CI 0.57-1.67) of hepatocellular carcinoma patients in liver transplantation.

CONCLUSIONS

For patients with malignant disease, intraoperative blood salvage did not increase the tumor recurrence rate and had comparable survival outcomes with allogeneic blood transfusion.

Trial of intraoperative cell salvage versus transfusion in ovarian cancer (TIC TOC): protocol for a randomised controlled feasibility study

INTRODUCTION

Ovarian cancer is the leading cause of death from gynaecological cancer, with more than 7000 new cases registered in the UK in 2014. In patients suitable for surgery, the National Institute of Health and Care Excellence guidance for treatment recommends surgical resection of all macroscopic tumour, followed by chemotherapy. The surgical procedure can be extensive and associated with substantial blood loss which is conventionally replaced with a donor blood transfusion. While often necessary and lifesaving, the use of donor blood is associated with increased risks of complications and adverse surgical outcomes. Intraoperative cell salvage (ICS) is a blood conservation strategy in which red cells collected from blood lost during surgery are returned to the patient thus minimising the use of donor blood. This is the protocol for a feasibility randomised controlled trial with an embedded qualitative study and feasibility economic evaluation. If feasible, a later definitive trial will test the effectiveness and cost-effectiveness of ICS reinfusion versus donor blood transfusion in ovarian cancer surgery.

METHODS AND ANALYSIS

Sixty adult women scheduled for primary or interval ovarian cancer surgery at participating UK National Health Service Trusts will be recruited and individually randomised in a 1:1 ratio to receive ICS reinfusion or donor blood (as required) during surgery. Participants will be followed up by telephone at 30 days postoperatively for adverse events monitoring and by postal questionnaire at 6 weeks and 3 monthly thereafter, to capture quality of life and resource use data. Qualitative interviews will capture participants' and clinicians' experiences of the study.

ETHICS AND DISSEMINATION

This study has been granted ethical approval by the South West-Exeter Research Ethics Committee (ref: 16/SW/0256). Results will be disseminated via peer-reviewed publications and will inform the design of a larger trial.

TRIAL REGISTRATION NUMBER

ISRCTN19517317.

Current Status of the Use of Salvaged Blood in Metastatic Spine Tumour Surgery

To review the current status of salvaged blood transfusion (SBT) in metastatic spine tumour surgery (MSTS), with regard to its safety and efficacy, contraindications, and adverse effects. We also aimed to establish that the safety and adverse event profile of SBT is comparable and at least equal to that of allogeneic blood transfusion. MEDLINE and Scopus were used to search for relevant articles, based on keywords such as "cancer surgery," "salvaged blood," and "circulating tumor cells." We found 159 articles, of which 55 were relevant; 20 of those were excluded because they used other blood conservation techniques in addition to cell salvage. Five articles were manually selected from reference lists. In total, 40 articles were reviewed. There is sufficient evidence of the clinical safety of using salvaged blood in oncological surgery. SBT decreases the risk of postoperative infections and tumour recurrence. However, there are some limitations regarding its clinical applications, as it cannot be employed in cases of sepsis. In this review, we established that earlier studies supported the use of salvaged blood from a cell saver in conjunction with a leukocyte depletion filter (LDF). Furthermore, we highlight the recent emergence of sufficient evidence supporting the use of intraoperative cell salvage without an LDF in MSTS.

Transfusion-related immunomodulation: a reappraisal

PURPOSE OF REVIEW

This review summarizes current and prior observations regarding transfusion-related immunomodulation (TRIM) and puts these ideas into a modern immunological context, incorporating concepts from innate, adaptive, and nutritional immunity. We propose that TRIM research focus on determining whether there are specific, well-defined immunosuppressive effects from transfusing 'pure' red blood cells (RBCs) themselves, along with the by-products produced by the stored RBCs as a result of the 'storage lesion.' Macrophages are a key cell type involved in physiological and pathological RBC clearance and iron recycling. The plasticity and diversity of macrophages makes these cells potential mediators of immune suppression that could constitute TRIM.

RECENT FINDINGS

Recent reports identified the capacity of macrophages and monocytes to exhibit 'memory.' Exposure to various stimuli, such as engulfment of apoptotic cells and interactions with ß-glucan and lipopolysaccharide, were found to induce epigenetic, metabolic, and functional changes in certain myeloid cells, particularly macrophages and monocytes.

SUMMARY

Macrophages may mediate the immunosuppressive aspects of TRIM that arise as a result of transfused RBCs and their storage lesion induced by-products.

The prognostic role of perioperative allogeneic blood transfusions in gastric cancer patients undergoing curative resection: A systematic review and meta-analysis of non-randomized, adjusted studies

The impact of allogeneic perioperative blood transfusions (APTs) on the prognosis of gastric cancer patients undergoing curative-intent gastrectomy is still a highly debated topic. Two meta-analyses were published in 2015, and new studies report conflicting results. A literature review was conducted using PubMed, Scopus, the Cochrane Central Register of Controlled Trials and the Cochrane Database of Systematic Reviews, updated to March 1, 2016. Thirty-eight non-randomized studies reporting data on overall survival (OS), disease-free survival (DFS), disease-specific survival (DSS) and postoperative complications (PCs) were included. An inverse variance random-effects meta-analysis was conducted. APTs showed an association with worse OS, DFS, DSS and an increased number of PCs. The hazard ratio (HR) for OS was 1.49, with a 95% confidence interval (95% CI) of 1.32-1.69 (p < .00001; Q-test p = .001, I-squared = 56%). After outlier exclusion, the HR for OS was 1.34 (95% CI = 1.23-1.45, p < .00001; Q-test p = .64, I-squared = 0%). The HR for DFS was 1.48 (95% CI = 1.18-1.86, p = .0007; Q-test p = .31, I-squared = 16%), and the HR for DSS was 1.66 (95% CI = 1.5-2.19, p = .0004; Q-test p = .96, I-squared = 0%). The odds ratio for PCs was 3.33 (95% CI = 2.10-5.29, p < .00001; Q-test p = .14, I-squared = 42%). This meta-analysis showed a significant association between transfusions and OS, DFS, DSS and PCs. The quality of the evidence was low. Aggregation, selection and selective reporting bias were detected. The biases shifted the results towards significance. Further studies using accurate adjustment methods are needed. Until such additional studies are performed, caution in administering transfusions and optimization of cancer patient blood management are warranted.