Ultrasound is a poor predictor of early or overt liver or spleen metastasis in dogs with high‐risk mast cell tumours

Abstract

Conflicting evidence exists regarding the importance of routine abdominal ultrasound (US) with hepatic and splenic fine needle aspiration (FNA) cytology during staging of canine mast cell tumours (MCT). The objective of this study was to correlate ultrasonographic and cytologic findings in dogs with strictly defined high-risk MCTs and to determine the influence on outcome. Our hypothesis was that US poorly predicts visceral metastasis in high-risk MCTs and that early metastasis is associated with improved outcome when compared to overt metastasis. US of liver and spleen correlated to cytologic results, categorized as no metastasis, early metastasis or overt metastasis. Of 82 dogs prospectively enrolled, 18% had early visceral metastasis and 7% had overt metastasis on cytology; 67% with visceral metastasis had regional LN metastasis. US was a poor predictor of metastasis with sensitivity, specificity, positive predictive value and negative predictive value for the spleen of 67%, 68%, 21% and 94%, respectively and for the liver of 29%, 93%, 56% and 82%, respectively. Median time to progression (TTP) for dogs with no metastasis, early metastasis and overt metastasis was not reached, 305 and 69 days, respectively (P < .001). Median survival time (MST) for the 3 groups were not reached, 322 and 81 days, respectively (P < .001). High Patnaik or Kiupel grade, early metastasis, overt metastasis and adequate local control were significantly associated with outcome. Early visceral metastasis was associated with poorer outcome compared to dogs without metastasis, however, a subset of dogs experienced long-term control.

Variability in Recommendations for Cervical Lymph Node Pathology for Staging of Canine Oral Neoplasia: A Survey Study

“…This was especially surprising given that existing literature suggests that lymph node size, imaging appearance, and cytologic evaluation are limited in accurately determining nodal metastasis for canine OMM (3,8,9,13,15,17). It is possible that respondents have factored in several findings in their clinical management strategies, such as: the uncertainty in the true rate of cervical lymph node metastasis in canine OMM in part due to lack of standardized assessment, that the literature has not always shown lymph node metastasis to be a negative prognostic factor, and that distant metastasis is particularly problematic for many cases (7,(53)(54)(55)(56). The risk of concurrent distant metastasis may also explain why END was not increasingly performed with advancing tumor size for OMM.…”

“…Unlike OMM, where distant metastasis poses a significant clinical challenge (5,7,52,63), literature supports that adequate local control of the primary tumor and regional nodes is the most important facet for longterm control for dogs with MCTs (54-56). Thus, it was surprising that given the high propensity for oral MCT to metastasize to lymph nodes and the significant effect of nodal metastasis on median survival time, that END is not recommend more often for the N0 neck (54)(55)(56). Rather, in 53% of cases, nodes are extirpated only if suspicious for metastasis on imaging or cytologically confirmed as metastatic.…”

Assessing the Risk of Nodal Metastases in Canine Integumentary Mast Cell Tumors: Is Sentinel Lymph Node Biopsy Always Necessary?

“…These results highlight the importance of SLN mapping and biopsy to achieve an accurate and personalized nodal staging and undermine the prognostic results reported in the previous studies focused on RLN evaluation. Conversely, SLN mapping and biopsy include additional anesthetics, diagnostic and surgical procedures, and additional costs for the owner, although to date there are no data available on the clinical benefits of these procedures, especially in case of non-high metastatic risk MCT [ 8 , 9 , 10 ]. Furthermore, information is lacking on the potential morbidity related to the removal of non-metastatic SLN.…”

Contrast‐enhanced ultrasound for sentinel lymph node mapping in the routine staging of canine mast cell tumours: A feasibility study

“…The main disadvantages are the need to select which lymphatic basins to scan, and inter‐operator variability. This technique seems however particularly advantageous for dogs with MCTs as abdominal ultrasound (US) and liver/spleen US‐guided FNAC are already often performed for their staging 3,38‐40 …”

“…This technique seems however particularly advantageous for dogs with MCTs as abdominal ultrasound (US) and liver/spleen US-guided FNAC are already often performed for their staging. 3,[38][39][40] Our hypothesis was that CEUS SLN mapping could be integrated into the routine staging of canine MCTs, from both practical and technical aspects. The primary objective was to determine the safety and effectiveness of CEUS to identify SLNs.…”