Intraoperative autologous blood recovery in prostate cancer surgery:in vivovalidation using a tumour marker

Assessment of thermally stabilized electrospun poly(vinyl alcohol) materials as cell permeable membranes for a novel blood salvage device

The use of Intraoperative Cell Salvage (ICS) is currently limited in oncological surgeries, due to safety concerns associated with the ability of existing devices to successfully remove circulating tumour cells. In this work, we present the first stages towards the creation of an alternative platform to current cell savers, based on the extremely selective immunoaffinity membrane chromatography principle. Non-woven membranes were produced via electrospinning using poly(vinyl alcohol) (PVA), and further heat treated at 180 °C to prevent their dissolution in aqueous environments and preserve their fibrous morphology. The effects of the PVA degree of hydrolysis (DH) (98 % vs 99 %), method of electrospinning (needleless DC vs AC), and heat treatment duration (1-8 h) were investigated. All heat treated supports maintained their cytocompatibility, whilst tensile tests indicated that the 99 % hydrolysed DC electrospun mats were stronger compared to their 98 % DH counterparts. Although, and at the described conditions, AC electrospinning produced fibres with more than double the diameter compared to those from DC electrospinning, it was not chosen for subsequent experiments because it is still under development. Evidence of unimpeded passage of SY5Y neuroblastoma cells and undiluted defibrinated sheep's blood in flow-through filtration experiments confirmed the successful creation of 3D networks with minimum resistance to mass transfer and lack of non-specific cell binding to the base material, paving the way for the development of novel, highly selective ICS devices for tumour surgeries.

[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.

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.

Metastatic efficiency of tumour cells can be impaired by intraoperative cell salvage process: truth or conjecture?

The use of salvaged blood in oncological surgery has been a matter of controversy over the years. This is due to the concern of systemic dissemination of reinfused tumour cells. Recent literature, across disciplines, has shed considerable light on its safety in terms of tumour recurrence, progression and overall survival rates. This clinical safety demonstrates the apparent metastatic inefficiency of reinfused tumour cells. The proof of this concept comes from various studies that have shown that salvaged blood has no tumour cells, or has a significantly lower count as compared to the patient's original circulatory tumour load. Recently, we took a step further and found that the tumour cells in the salvaged blood lose the capacity to replicate. In this review, we revisited the safety of salvaged blood from the point of view of metastatic potential. We have presented basic and applied science evidence regarding the innocuous nature of tumour cells that have been subjected to the cell salvage process. The understanding of the metastatic efficiency or the lack of it in tumour cells subjected to salvage process is key to allay the concerns conventionally associated with the use of salvaged blood in tumour surgery. Based on the available literature, we surmise that the prevalent apprehensions on the usage of salvaged blood are ill-founded and further substantiate why tumour cells in the salvaged blood could be regarded as cells with non-metastatic potential.

Are we ready for the use of intraoperative salvaged blood in metastatic spine tumour surgery?

PURPOSE

To evaluate the feasibility of using intraoperative cell salvage (IOCS) in combination with leucocyte depletion filter (LDF) in eliminating tumour cells from blood salvaged during metastatic spine tumour surgery (MSTS). This is with the view to pave the path for use of IOCS-LDF in MSTS and musculoskeletal oncological surgery.

METHODS

Sixty consecutive patients with known primary epithelial tumour, who were offered surgery for metastatic spine disease at our university hospital, were recruited. Blood samples were collected at three different stages during surgery: from operative field prior to IOCS processing, after IOCS processing and after IOCS-LDF processing. Three separate samples (5 ml each) were taken at each stage. Samples were examined by cell block technique using immunohistochemical monoclonal antibodies to identify tumour cells of epithelial origin in the samples.

RESULTS

Of 60 patients, ten were excluded for not fulfilling the inclusion criteria leaving 50 patients. Malignant tumour cells were detected in the samples from operative field prior to IOCS processing in 24 patients and in the samples from the transfusion bag post-IOCS processing in 4 patients. No viable malignant cells were detectable in any of the blood samples after passage through both IOCS and LDF.

CONCLUSIONS

The findings support the notion that IOCS-LDF combination works effectively in eliminating tumour cells from salvaged blood so this technique can possibly be applied in MSTS and even musculoskeletal oncological surgery. This concept can then be extended to other oncological surgeries in general with further appropriate clinical studies.

Irradiation Can Selectively Kill Tumor Cells while Preserving Erythrocyte Viability in a Co-Culture System

An understanding of how to safely apply intraoperative blood salvage (IBS) in cancer surgery has not yet been obtained. Here, we investigated the optimal dose of ¹³⁷Cs gamma-ray irradiation for killing human hepatocarcinoma (HepG2), gastrocarcinoma (SGC7901), and colonic carcinoma (SW620) tumor cells while preserving co-cultured erythrocytes obtained from 14 healthy adult volunteers. HepG2, SGC7901, or SW620 cells were mixed into the aliquots of erythrocytes. After the mixed cells were treated with ¹³⁷Cs gamma-ray irradiation (30, 50, and 100 Gy), tumor cells and erythrocytes were separated by density gradient centrifugation in Percoll with a density of 1.063 g/ml. The viability, clonogenicity, DNA synthesis, tumorigenicity, and apoptosis of the tumor cells were determined by MTT assay, plate colony formation, 5-ethynyl-2'-deoxyuridine (EdU) incorporation, subcutaneous xenograft implantation into immunocompromised mice, and annexin V/7-AAD staining, respectively. The ATP concentration, 2,3-DPG level, free Hb concentration, osmotic fragility, membrane phosphatidylserine externalization, blood gas variables, reactive oxygen species levels, and superoxide dismutase levels in erythrocytes were analyzed. We found that ¹³⁷Cs gamma-ray irradiation at 50 Gy effectively inhibited the viability, proliferation, and tumorigenicity of HepG2, SGC7901, and SW620 cells without markedly damaging the oxygen-carrying ability or membrane integrity or increasing the oxidative stress of erythrocytes in vitro. These results demonstrated that 50 Gy irradiation in a standard ¹³⁷Cs blood irradiator might be a safe and effective method of inactivating HepG2, SGC7901, and SW620 cells mixed with erythrocytes, which might help to safely allow IBS in cancer surgery.

Flow cytometric evaluation of the safety of intraoperative salvaged blood filtered with leucocyte depletion filter in spine tumour surgery

BACKGROUND

Intraoperative cell salvage (IOCS) has not been widely adopted in oncological surgery due to the hypothetical concern of reinfusion of malignant cells. We evaluated the feasibility of IOCS in combination with leucocyte depletion filter (LDF) in metastatic spine tumour surgery (MSTS).

METHODS

Patients with known primary epithelial tumour, operated for metastatic spinal disease, were recruited. Blood samples were collected at five different stages during surgery: 2 stages from patient vein during induction and at the time of maximum tumour manipulation, 3 stages from the operative blood prior to IOCS processing, after IOCS processing, and after IOCS-LDF processing. Of the samples taken at each stage, 5 ml were analyzed for tumour cells using flow cytometry.

RESULTS

Of 12 patients recruited, only 11 could be finally analyzed. Flow cytometry analysis of their samples showed that 8 of 11 patients had tumour cells in the unfiltered salvaged blood. In filtered salvaged blood, the tumour cell count was zero in the majority of samples (8/11 patients), whereas three patients' samples had a few tumour cells. The mean difference between the tumour cell quantity in the samples from the patient vein and filtered salvaged blood was significant.

CONCLUSIONS

IOCS-LDF was shown to be effective in removing tumour cells from the blood salvaged during MSTS. If there were any tumour cells found, the quantity was significantly less than that in the patient's circulation. The results of this study reiterates the conclusions of our previous published work where we showed that IOCS-LDF treated blood in MSTS is safe for transfusion.

Should intraoperative cell-salvaged blood be used in patients with suspected or known malignancy?

PURPOSE

Intraoperative cell salvage (ICS) is used as an alternative to allogeneic blood transfusion in an attempt to avoid or minimize the risks associated with allogeneic blood. Intraoperative cell salvage is generally avoided in surgeries where malignancy is confirmed or suspected due to concern for potential metastasis or cancer recurrence. The application of post-processing methods for ICS is hypothesized to eliminate this potential risk. The purpose of this narrative review is to examine the in vitro experimental evidence as it pertains to the removal of tumour cells from ICS blood and to review the clinical studies where ICS blood has been used in patients with malignancy.

SOURCE

A search of the English literature for relevant articles published from 1973 to 2012 was undertaken using MEDLINE and Cochrane databases. Bibliographies were cross-referenced to locate further studies.

PRINCIPAL FINDINGS

Leukoreduction filters are an effective method for removal of malignant cells from ICS blood. Small non-randomized clinical studies to date do not show evidence of an increased rate of metastasis or cancer recurrence. Although a theoretical risk of disease recurrence persists, the decision to use autologous ICS blood must be weighed against the known risks of allogeneic blood transfusion.

CONCLUSION

Transfusion of autologous blood harvested via ICS should be considered a viable option for reduction or avoidance of allogeneic product during many oncologic surgeries and may be a lifesaving option for those patients who refuse allogeneic blood products.