The impact of extirpation of non‐palpable/normal‐sized regional lymph nodes on staging of canine cutaneous mast cell tumours: A multicentric retrospective study

Abstract

Metastasis to regional lymph nodes (RLNs) in dogs with cutaneous mast cell tumour (cMCT) has been correlated with shortened survival time and higher risk of spread to distant sites. In the present study, extirpation of non-palpable or normal-sized RLNs was included in the surgical management of cMCT in dogs. Correlations between histological nodal status (HN0-3) and tumour variables were analysed. Ninety-three dogs with single cMCT without distant metastasis that underwent wide surgical excision of the primary tumour and extirpation of non-palpable or normal-sized RLN were included. The association between HN (HN0 vs HN > 0; HN0-1 vs HN2-3) and tumour variables (site, longest diameter, ulceration, 3-tier and 2-tier histological grades) was analysed by a generalized linear model with multinomial error. Then, 33 (35.5%) RLNs were HN0, 14 (15%) were HN1, 26 (28%) were HN2 and 20 (21.5%) were HN3. The presence of positive (HN > 0) RLN was significantly associated with cMCT larger than 3 cm. No other association was statistically significant. Non-palpable/normal-sized RLN in dogs with cMCT can harbour histologically detectable metastatic disease in nearly half of the cases. Extirpation of the RLN should always perfomed to obtain a correct staging of the disease, even in the absence of clinical suspicion of metastasis. Further studies should evaluate the possible therapeutical effect of the tumour burden reduction obtained by exrtipartion of a positive RLN.

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

“…15,16 It is however higher than the 42% previously reported in our institution when SLN mapping was not part of the routine staging, 12 and the 45.9% reported in another study. 13 This supports the effectiveness of CEUS SLN mapping; but unlike in these two retrospective studies, in this current study all histological sections were stained with toluidine blue, which may also have affected these results.…”

“…10,11 With a reported 75% sensitivity of fine-needle aspiration cytology (FNAC) to detect MCT nodal metastasis, LN extirpation has also been recommended to complete MCT staging. 12,13 Lymphadenectomy is an invasive procedure that often necessitates additional surgical preparation and time, extending time under anaesthesia for dogs and costs for owners. It is therefore sometimes difficult to justify when the LN draining status is uncertain and/or when the LN is particularly difficult to remove.…”

Comparative aspects of mast cell neoplasia in animals and the role of KIT in prognosis and treatment

“…Clinical stage II is defined as a single tumour with regional lymph node metastasis. Assessment of regional nodes is most accurately accomplished by node excision and histopathology (Ferrari et al, ; Weishaar, Thamm, Worley, & Kamstock, ). A worse outcome for dogs with clinical stage II than with clinical stage 0/I MCT has been documented (Krick, Billings, Shofer, Watanabe, & Sorenmo, ; Murphy et al, ; Weishaar et al, ).…”

miRNA profiles of canine cutaneous mast cell tumours with early nodal metastasis and evaluation as potential biomarkers

“…Although the prognostic role of both the Patnaik 5 and Kiupel 4 grading systems in canine MCTs is widely accepted, histological grading alone cannot accurately predict the risk of local and distant metastases 3 – 5 , 9 , 49 . Nodal metastases have been reported in 20–49% of cutaneous MCTs at first presentation, and identification of lymph node involvement is crucial for accurate tumour staging and prognosis 3 , 49 , 50 . Recently, a novel classification system for the evaluation of nodal metastasis in canine MCTs has been proposed and correlated with the clinical outcome, providing evidence that dogs diagnosed with early metastatic/overt metastatic (HN2-HN3) nodes have a shorter life expectancy 7 .…”