From the FDA Drug Label
The effect of bleomycin is significantly enhanced if vinblastine sulfate is administered six to eight hours prior to the administration of bleomycin; this schedule permits more cells to be arrested during metaphase, the stage of the cell cycle in which bleomycin is active.
The FDA drug label does not answer the question.
From the Research
Administering vinblastine prior to surgical removal of a mass in a dog can be beneficial in certain cases, particularly for mast cell tumors, with the most recent evidence suggesting a dose of 2-2.5 mg/m² intravenously, typically 1-2 weeks before surgery, as the most effective protocol 1. The recommended protocol should be done under veterinary supervision with appropriate premedication including an antihistamine (such as diphenhydramine at 2 mg/kg) and a steroid (such as dexamethasone at 0.2 mg/kg) to prevent histamine release. Some key points to consider when administering vinblastine include:
- Vinblastine administration requires careful handling as it's a vesicant that can cause severe tissue damage if extravasated, and should only be administered through a secure IV catheter.
- Blood work should be performed before treatment to ensure adequate bone marrow function, and again before surgery to confirm the dog has recovered from any potential myelosuppression.
- The rationale for preoperative vinblastine is to reduce tumor size, decrease the risk of mast cell degranulation during surgery, and potentially eliminate micrometastases.
- This approach may improve surgical outcomes by allowing for cleaner margins during mass removal and reducing the risk of systemic effects from mast cell mediator release during tumor manipulation. However, this protocol is specifically indicated for suspected or confirmed mast cell tumors and may not be appropriate for other tumor types, as evidenced by studies such as 2 which showed minimal efficacy in dogs with treatment-naive, multicentric lymphoma. In contrast, studies like 3 and 4 have demonstrated the efficacy of vinblastine in treating canine mast cell tumors, with response rates and toxicity profiles supporting its use in this context. More recent research, such as 5 and 1, has further refined the understanding of vinblastine's role in canine oncology, highlighting its potential benefits when used in combination with other agents or as part of a neoadjuvant chemotherapy protocol. Overall, the decision to administer vinblastine prior to surgical removal of a mass in a dog should be made on a case-by-case basis, taking into account the specific tumor type, the dog's overall health, and the potential risks and benefits of the treatment, as supported by the most recent and highest quality evidence available 1.