Authors (including presenting author) :
KF Wong (1), TK Fung (1), SW Yu (1), SL Cheung (1), WF Wong (1), PC Yam (1), CW Yiu (1), HL Yiu (1), SK Leung (1)
Affiliation :
(1) Department of Surgery, Tuen Mun Hospital, New Territories, Hong Kong (HKSAR)
Introduction :
Complete tumour excision is the basic principle of curative surgery. However, it is questionable whether surgery itself will cause tumour spillage. Before this study, no clinical data to support this concept.
Objectives :
We aimed to investigate (1) whether there is tumour spillage during operations, (2) various potential routes of tumour cells spillage during operations, and (3) the impact of cancer surgery per se upon tumour cells spillage.
We called these spilt tumour cells during operations the Escapee Tumour cells (ET cells).
Methodology :
A prospective cohort study was conducted (1/2019 to 3/2022). 133 tumour-related operations were performed. Routine operating field toileting was performed by using warm normal saline before the end of operations. A filter was connected to the suction device throughout the whole operation. Sediments (not the fluid) being trapped by the filter were sent for histopathology (not the cytology) to look for the presence of ET cells.
Patients’ demographic data, clinical information, operation details and histopathological findings of tumour and residue samples were reviewed. Univariate and then multi-variable logistic regression model was used to analyze the presence and potential routes of ET cells spread. To study the long term impact (recurrence rate and long term survival), we focused and further analyze those CA stomach cases only (133 cases). Type I error adopted was 0.05.
Result & Outcome :
In 133 patients, 26 (19.5%) and 16 (12%) of the collected residue showed the presence of ET cells and atypical cells respectively.
Upon univariate analysis, variables, including sex, age, BMI, residue block taken, volume of residue saved, tumour cells differentiation, neo-adjuvant therapy, extended lymph node dissection, operation time, operating blood loss and presence of lymph-vascular/ peri-neural invasion, no statistically significant difference was detected between ET-positive and ET-negative groups.
Variables deemed associated significantly with ET cell status in univariate analysis were further analyzed by using multi-variable logistic regression model.
Incomplete resection (R1, R2 resection, p-value: 0.005, B-value: 1.519), advanced N-stage (N2 or N3 disease, p-value: 0.031, B-value: 1.510) and certain cancer type (oesophageal cancer in this study, p-value: 0.027, B-value: -1.567) are the statistical significant factors related with the presence of ET cells.
For the long term impact, ET cells positive cases were found to have a significant higher recurrence rate (52.4% vs 26.8%, P-value 0.024), faster recurrence rate (6.4 months vs 13.2 months, P-value 0.04), shorter survival time (13.7 months vs 29.5 months, P-value 0.001) and lower 3-year survival rate (4.8% vs 36.7%, P-value 0.019).
For the first time, this study provides the scientific prove for the presence of ET cells in oncological surgery resection. It also suggests potential routes of ET cells spillage and gives us the insight of the clinical significance of ET cells and prevention of tumour spillage during operations in the future.
The presence of ET cells was shown to have significant implication on clinical outcomes in terms of tumour recurrence and survival.
