#91 Eliminating Tumour Cells from the Cell Saver (CS) in Metastatic Spine Tumour Surgery Using a Leucocyte Depletion Filter (LDF): Dispelling an Old Myth

General Session: Best Papers Session 2

Presented by: Y. Chen

Author(s):

Y. Chen (1)
N.S. Kumar (1)
Q. Ahmed (2)
V. Lee (2)
R.W.M. Lam (1)
H.K. Wong (1)

(1) National University Health System, Department of Orthopaedic Surgery, Singapore, Singapore
(2) National University Health System, Department of Pathology, Singapore, Singapore

Abstract

Design: Prospective observational study.

Background: Catastrophic bleeding is a significant problem in metastatic spine tumor surgery(MSTS). However, cell savers(CS) have traditionally been avoided in tumour surgery because of the theoretical concern of promoting tumour dissemination by re-infusing tumour cells into the circulation. Although CS has been extensively investigated in patients undergoing surgery for gynaecological, lung, urological, gastrointestinal, and hepatobiliary cancers, to date, there is no prior report of the use of CS in MSTS.

Hypothesis: Our hypothesis is that LDF can eliminate tumour cells from blood salvaged during metastatic spine tumour surgery.

Materials and Method: After Institutional Review Board (IRB) approval, 15 consecutive patients with metastatic spinal tumours from a known epithelial primary (defined as originating from breast, prostate, thyroid, renal, colorectal, lung, nasopharyngeal, hepatocellular) who were scheduled for MSTS were recruited with informed consent.

During surgery, a CS device (Dideco, Sorin Group, Italy) was used to collect shed blood from the operative field. Salvaged blood was then passed through a leucocyte depletion filter (RS1VAE, Pall Corporation, Portsmouth, UK). 15-ml specimens of blood were taken from each of three consecutive stages:

(i) from the operative field prior to cell saver processing(Stage A);

(ii) from the transfusion bag post-cell saver processing(Stage B);

(iii) from the filtered blood after passage through LDF(Stage C).

Cell blocks were prepared by the pathology department using a standardized laboratory protocol. From each cell block, 1 haematoxylin and eosin(H&E) slide, and 3 slides each labeled with one of the following monoclonal mouse cytokeratin antibiodies AE1/3, MNF 116 and CAM 5.2 were prepared. The cytokeratin antibiodies are highly sensitive and specific markers to identify tumour cells of epithelial origin. These slides were read by one of two consultant pathologists who was provided full access to information on the histology of the primary tumour and operative notes, but was blinded to the actual stages from which the slides were derived.

Results: 1 case was excluded when final diagnosis was revised to infection instead of metastatic spine tumour. Of the remaining cases, 5/14 tested positive for tumour in Stage A, 1/14 positive in Stage B. No specimen tested positive for tumour in Stage C. In 5 cases, posterior instrumentation without tumour manipulation was performed.

Conclusion: In this first-ever report of cell saver use in spine tumour surgery, we prove that:

(i) Leucocyte-depletion filters(LDF) can effectively eliminate tumour cells from blood salvaged during MSTS.

(ii) It is now possible to conduct a clinical trial to evaluate CS-LDF use in MSTS.

Our results are consistent with published results of similar studies performed on CS and LDF use outside the field of spine and orthopaedic surgery.

Spinal metastases originate from a myriad of primary cancers across various organ systems. If LDF can remove tumor cells from blood salvaged during surgery for spinal metastasis of different histological origin, then the finding can likely be extrapolated to several other fields of surgery where cell salvage and LDF have also not yet been attempted such as in neurosurgery, otolaryngology and even general musculoskeletal oncology.