From the Guidelines
Metronomic chemotherapy is recommended as a follow-up treatment after cisplatin for canine osteosarcoma (OSA). A typical protocol involves cyclophosphamide at 10-15 mg/m² daily or every other day, combined with a non-steroidal anti-inflammatory drug (NSAID) such as piroxicam (0.3 mg/kg daily) or meloxicam (0.1 mg/kg daily) 1. This regimen typically begins 2-3 weeks after completing cisplatin therapy and continues long-term, often for 6-12 months or longer if well-tolerated.
Key Considerations
- Regular monitoring is essential, including complete blood counts every 2-4 weeks initially, then monthly, to check for myelosuppression.
- Urinalysis should be performed every 1-2 months to monitor for sterile hemorrhagic cystitis, a potential side effect of cyclophosphamide.
- Metronomic chemotherapy works differently from conventional high-dose chemotherapy by targeting tumor blood vessel formation (anti-angiogenesis) rather than directly killing cancer cells.
- The combination with NSAIDs enhances anti-angiogenic effects and provides pain control.
Rationale
The most recent and highest quality study, published in 2021, supports the use of metronomic chemotherapy as a follow-up treatment after cisplatin for canine osteosarcoma (OSA) 1. This approach provides continuous low-dose exposure to chemotherapeutic agents, potentially reducing metastasis risk while offering fewer side effects than conventional chemotherapy.
Treatment Protocol
- Cyclophosphamide: 10-15 mg/m² daily or every other day
- NSAID: piroxicam (0.3 mg/kg daily) or meloxicam (0.1 mg/kg daily)
- Monitoring: complete blood counts every 2-4 weeks initially, then monthly; urinalysis every 1-2 months This maintenance therapy is particularly valuable for OSA patients after completing cisplatin, as it may help delay or prevent metastatic disease, which is common in canine OSA even after limb amputation and conventional chemotherapy 1.
From the Research
Metronomic Chemotherapy after Cisplatin Treatment for OSA in Dogs
- There is no direct evidence in the provided studies regarding metronomic chemotherapy after cisplatin treatment for Osteosarcoma (OSA) in dogs.
- However, the studies discuss various treatment options for OSA in dogs, including cisplatin and doxorubicin chemotherapy 2, 3, 4, 5, 6.
- Cisplatin is a commonly used chemotherapy drug for treating OSA in dogs, and it has been shown to improve survival times when used in combination with surgery 4, 5, 6.
- The use of metronomic chemotherapy, which involves the continuous administration of low-dose chemotherapy, is not mentioned in the provided studies.
- The studies focus on the use of conventional chemotherapy protocols, such as cisplatin and doxorubicin, to treat OSA in dogs 4, 5, 6.
- Further research is needed to investigate the efficacy of metronomic chemotherapy after cisplatin treatment for OSA in dogs.