If surgical margins are clean (tumor - free microscopically), chemotherapy with mitoxantrone or carboplatin (once every 3 weeks for 5 - 6 total treatments post-operatively). (veterinarycancer.com)
When combined with the IV chemotherapy drug Mitoxantrone, treatment efficacy with Piroxicam resulted in even better results than using Piroxicam alone. (1800petmeds.com)
As mentioned above, approximately 35 % of dogs receiving mitoxantrone and piroxicam have remission, and the average survival is around 250 - 300 days. (vet.purdue.edu)