Adherence of malignant cells to surgical gloves and instruments in canine oncological surgeries: a pilot study

OBJECTIVE: To determine the frequency of adherence of malignant cells to surgical gloves and instruments during canine oncological surgeries and assess whether histopathological margin status or tumour type influences the presence of tumour cells. MATERIALS AND METHODS: A prospective pilot study was conducted on 47 dogs undergoing resection of primary solid tumours. Following tumour excision, the primary surgeon changed gloves and instruments, which were then irrigated with ThinPrep® solution. Samples were processed via cytospin centrifugation, stained with May-Grünwald Giemsa and evaluated by a board-certified clinical pathologist. Malignant cells were quantified as low (100). Statistical analysis assessed associations between histopathological margin status, tumour type and the presence of malignant cells. RESULTS: Malignant cells were detected in glove and/or instrument washings in 14/47 (30%) cases. Among the 14 primary tumours with histopathologically involved (incomplete) margins, malignant cells were detected in glove and/or instrument washings in 8/14 (57%) cases, compared with 6/32 (19%) cases with histopathologically clear margins. There was a statistically significant association between margin status and contamination (P = .016). No significant association was found between tumour type and contamination. CLINICAL SIGNIFICANCE: This study is the first to document malignant cell contamination on surgical gloves and instruments in veterinary oncological surgery. While contamination was more likely with incomplete margins, tumour cells were detected in 30% of cases overall. These findings highlight a potential risk of iatrogenic tumour seeding and support routine glove and instrument changes following tumour excision.