A retrospective review of treatment and response of high‐risk mast cell tumours in dogs

Abstract

This retrospective case series evaluates survival outcome of 94 dogs with high metastatic risk mast cell tumours (MCT). Patients were treated with a cytotoxic chemotherapy protocol or the tyrosine kinase inhibitor masitinib, in the presence of gross disease or as an adjunct to surgical resection of the primary tumour. In patients presenting with metastatic disease, surgical resection of the primary tumour with adjunctive therapy with any chemotherapy incurred a significant survival advantage [median survival time (MST): 278 days] compared to patients receiving chemotherapy without surgical excision of the primary tumour (MST: 91 days, P < 0.0001). Patients with a surgically excised Patnaik grade II tumour and high Ki-67 in the absence of metastatic disease treated with vinblastine and prednisolone showed a significantly longer survival (MST: 1946 days) than those treated with masitinib (MST: 369 days, P = 0.0037). Further prospective case-controlled clinical trials of high-risk MCTs are required to make precise evidence-based treatment decisions for individual patients.

Outcome of adjuvant chemotherapy with lomustine, vinblastine and chlorambucil on management of canine mast cell tumour of high to intermediate risk

“…However, this finding was not noticed in this study, and was also not observed in the study by Miller et al (2014). In a study conducted by Michels et al (2002), the likelihood of recurrence in MCT with evidence of incomplete surgical margins was not higher than those with clean margins.…”

“…(Blackwood et al, 2012;London and Thamm, 2013;Miller et al, 2014) Patients at intermediate-risk (group B) were subdivided in three groups: B1, formed by patients treated with adjuvant vinblastine (Velban, ABL) at a dosage of 2 mg / m² every seven days, for four sessions, and then every 14 days for four more sessions followed by the eight-week chlorambucil protocol; B2, formed by patients treated with the eight-week protocol using chlorambucil; and B3 formed by patients whose owners declined any further treatment beyond surgery (intermediate-risk control).…”

“…As positive and negative controls, healthy canine skin samples and milique water were used, respectively. For this study, patients with diagnosed MCT were divided into three major groups, according to the risk of recurrence or metastasis, based on evaluated pronostic factors, relevant in the literature (Blackwood et al, 2012;London and Thamm, 2013;Miller et al, 2014), as shown in table 1.…”

“…A high risk of recurrence or metastasis is associated with tumours classified as a grade 3 MCT according to the Patnaik grading scheme, but also for the Patnaik intermediate grade, whenever there is a lymph node or distant metastasis and / or high growth fraction estimated by the mitotic count or Ki-67 immunoexpression (Romansik et al, 2007;Blackwood et al, 2012;London and Thamm, 2013;Miller et al, 2014), and for the MCT located in the mucousa or mucocutaneous junctions (London and Thamm, 2013). Other prognostic factors, may also be important for disease progression, such as tumour location (scrotum, prepuce, perineum or vulva), breed (London and Thamm, 2013) and KITr pattern expression (Kiupel et al, 2004).…”

Survey of UK‐based veterinary surgeons' opinions on the use of surgery and chemotherapy in the treatment of canine high‐grade mast cell tumour, splenic haemangiosarcoma and appendicular osteosarcoma

“…Metastasis prevention or delay is one of the main aims of adjuvant chemotherapy (Ogilvie 1998). Due to the risk of the development of metastatic disease in the aforementioned tumour types, adjuvant chemotherapy has been reported to reduce the risk of both local recurrence and further spread of these tumours (Moore and others 2007, Blacklock and others 2012, Miller and others 2014, Sharma and others 2014, Wendelburg and others 2015, Shorupski and others 2016). In one study, 70.8 per cent of general veterinary practitioners (GVPs) prescribed a cytotoxic drug for a canine or feline patient between November 2003 and November 2004 and, in the same period, 38.9 per cent of GVPs referred a patient to an oncologist for chemotherapy (Cave and others 2007).…”