Since my recent post about Brick’s Osteosarcoma diagnosis and treatment plan, we’ve met with some obstacles. Last Monday, a scheduled chest x-ray showed a single pulmonary nodule (lung metastasis). Because Osteosarcoma spreads most commonly to the lungs, we were disappointed but not entirely surprised by the findings. In light of the nodule, Brick’s oncologists proposed we trade out the original doxorubicin/carboplatin treatment plan for something more tailored to the current situation.

The new plan involves aerosolizing and inhaling a chemo drug called Gemcitabine and infusing a drug called ifosfamide. Gemcitabine is given in human medicine as an IV infusion for lung cancer. But inhaled Gemcitabine is currently being studied by the oncologists at UC Davis Veterinary Medical Teaching Hospital as a new means of stopping the growth of existing lung tumors. The goal of aerosolizing the drug is to provide direct access to any tumors that lie along major airways; in addition, the drug absorbs into the pulmonary tissue and reaches the tumors that are in the vicinity of those tissues. Once in contact with the tumor, it interferes with the tumor’s ability to synthesize DNA, thus arresting growth. In the UC Davis study, it is given twice a week using a nebulizer and mask.

Ifosfamide is a nitrogen mustard alkylating agent. In simpler terms, it’s a drug that’s related to mustard gas; and it interferes with the existing DNA in tumor cells, causing cell death. It’s used in human medicine for various sarcomas and Hodgkin’s disease. It is given every three weeks as an IV infusion over 6-8 hours with fluids.

For dogs with pulmonary metastases that do not pursue treatment, the median survival time (MST) is around 60 days. With treatment, we are hopeful we will have Brick closer to 8 months, which is the MST for this protocol. I will keep you posted.

 

[note: there is a follow up to this post, dated July 25, 2011]

Advertisements