Intratumoural Treatment of 18 Cytologically Diagnosed Canine High-Grade Mast Cell Tumours With Tigilanol Tiglate

Abstract

Canine high-grade mast cell tumours (HGMCT) are associated with a poor prognosis, are inherently more invasive, and have higher rates of local recurrence. The primary aim of this retrospective study was to assess the efficacy of intratumoural tigilanol tiglate (TT) as a local treatment option. Eighteen dogs with mast cell tumours (MCT) cytologically diagnosed by veterinary pathologists as either high-grade or suspected high-grade MCT were treated with TT. The TT dose was based on tumour volume (0.5 mg TT/cm3 tumour volume) and delivered intratumourally using a Luer lock syringe and a fanning technique to maximise distribution throughout the tumour mass. Efficacy was assessed on the presence/absence of a complete response (CR) to therapy at days 28 and 84 using response evaluation criteria in solid tumours (RECIST). For dogs not achieving a CR after 28 days, the protocol was repeated with a second intratumoural TT injection. Ten out of 18 dogs (56%) in this study achieved and maintained a CR to at least 84 days after their first or second treatment. Six patients were alive and available for evaluation at 2 years, three of those were recurrence free, and a further three patients were recurrence free following a second treatment cycle. Tigilanol tiglate shows efficacy for local treatment of HGMCT, with higher efficacy noted with a second injection if a CR was not achieved following the first treatment. In the event of treatment site recurrence (TSR), the tumour may be controlled with additional treatment cycles. Tigilanol tiglate provides an alternative local treatment approach to dogs with HGMCT that would either pose an unacceptable anaesthetic risk or the tumour location provides a challenge when attempting surgical excision.

Diagnosis, Prognosis and Treatment of Canine Cutaneous and Subcutaneous Mast Cell Tumors

“…Prednisone must be used before (0.5 mg/kg, every 12 h, for 2 days) and after (0.5 mg per kg every 24 h, for 3 days) the application, in addition to the use of promethazine (0.5–1.0 mg per kg every 12 h for 7 days); and ranitidine (2.0 mg per Kg, every 12 h for 7 days). When total tumor remission does not occur, TT can be reapplied after 28 days, although the volume must be calculated again [ 190 , 191 , 192 , 193 , 194 ].…”

Treatment of multiple synchronous canine mast cell tumours using intratumoural tigilanol tiglate

“…The study was conducted using protocols approved by the Queensland Department of Agriculture and Fisheries, Community Animal Ethics Committee (reference number CA 2020/11/1443), with written informed consent obtained from all owners prior to patient enrolment. Patients were required to satisfy eligibility criteria in relation to (a) general health, (b) evidence of metastatic disease (regional lymph node aspirates and abdominal ultrasound examination at the discretion of the treating specialist and consent of the owner), and (c) compliance with maximum label dose limits (a total dose rate of up to 0.25 ml/kg or no more than 5 ml per dog regardless of the number of tumours to be treated) ( 27 – 30 ). Fine needle aspirates of all target lesions were collected and submitted to Independent Veterinary Pathology (IVP, Australia) for cytological grading using the Camus system ( 34 ).…”

“…Dimensions of each tumour were measured with digital callipers, and then the volume(s) were calculated using a modified ellipsoid method where tumour volume = 0.5 × length ( cm ) × width ( cm ) × depth ( cm ) ( 36 , 37 ). The dose per tumour to be administered is 50% of each tumour's volume ( tigilanol tiglate volume = tumour volume × 0.5) and a minimum tumour dose of 0.1 ml ( 26 – 30 ). Personal protective equipment in the form of disposable gloves and protective eyewear were worn by the veterinarian and staff while the tigilanol tiglate dose was prepared and administered.…”

The use of tigilanol tiglate (Stelfonta®) for the treatment of canine mast cell tumors

“…Furthermore, all grades are officially eligible for treatment with Stelfonta ® . Yet, it is noteworthy to mention that tumors with an unfavorable cytological grading will less frequently have a complete response (Camus et al, 2016;Brown et al, 2021).…”