Canine Osteosarcoma – Our Experience Part III
It’s been about 8 weeks since our Maggie was diagnosed with Osteosarcoma. We’ve been through a lot since then and you can catch up on our story in our posts Part I and Part II.
Today I wanted to talk about our experience with chemotherapy. In addition to the SRS treatments, our vet recommended chemo treatment for Maggie to address any micrometasis from her OSA in other organs in her body. In 90% of the cases of dogs diagnosed with OSA, the cancer has already spread, so doing chemo is beneficial in reducing further spread and growth. Maggie’s OSA is considered early stage because they were unable to detect the spread of the cancer to other organs, so we want to do what we can to contain it.
I was concerned about harmful effects of the chemo as we had a bad experience with Becca. She got sick almost immediately, with a high fever, nausea, diarrhea – the whole gamut of side effects that might present itself. We stopped the treatment, and Becca regained some strength, but she never fully recovered. I certainly didn’t want the same for Maggie. One factor in our consideration was Maggie’s age and relative good health. While still a senior, Maggie is remarkably healthy for an eleven year old dog – excluding the cancer of course, so that went in the plus column.
I spent about 45 minutes with our Oncologist discussing the treatment, what to expect, what to expect if we didn’t treat her, what to do if she got sick, etc. Our vet, Dr. Rosenberg at Veterinary Cancer Group was so kind and patient with me. She has treated cancer patients for almost thirty years, so she has a breadth of experience that gave me a lot of comfort. She explained that 85% of dogs receiving chemo display no side effects at all, 14% display minor, short-lived effects and 1% show harmful side effects requiring hospitalization. Unfortunately, Becca fell into that category.
This is Maggie’s doctor:
Chemo drugs may be given orally (pill or liquid form), subcutaneous (injected under the skin), intra-lesional (injected into the tumor) or intra-muscular (injected into the muscle). The treatment of choice for OSA is a drug called Carboplatin. The treatment protocol is one dose every 2-3 weeks for a total of six treatments. In a nod to my concerns about Maggie reacting badly, we reduced the first dose. Treatment also calls for Pamidronite, a bone strengthener be administered every 3-4 weeks in addition to the Carboplatin.
As I’ve noted, these chemo drugs attack cells and work to interfere with cell division. Each drug may work in a different way to attack the cell division at different stages which is why multiple drugs may be recommended. Carboplatin contains platinum, a metal that helps to alter the DNA of cells that divide and split rapidly. Chemo drugs don’t discriminate between healthy and cancerous cells, they target cells that are dividing rapidly and because of this, normal cells in the body are also vulnerable. At particular risk are the GI tract and bone marrow as those cells divide more quickly than others in the body and are therefore more susceptible to the harmful impact of the chemotherapy drugs. The main symptoms to watch for are fever, nausea, vomiting, diarrhea, constipation, bloody urine or hair loss. Depending on the severity, your dog may be given antibiotics or be hospitalized to receive IV fluids.
Maggie’s first injection was Tuesday, August 29th and I’m happy to say so far she is in the 85% group with no side effects. We came home with instructions to take Maggie’s temperature each day as a safeguard against infection. We also administered anti-nausea drugs for the first four days. But I’m
happy ecstatic to report that Maggie has been fine. The only slight symptom she’s shown is she’s a bit more tired, but she’s eaten every meal, played her favorite “find the food” game everyday, gone for her daily walks and overall been her old self. I’m trying not to get ahead of myself as she has 5 more treatments, but I’m so relieved. In addition, her limp is gone. Although her running days are over, she has romped around the yard a bit and does not exhibit any signs of weakness or pain. We are slowly reducing her pain meds from the max dosage to the point where she is still pain free – we want to give ourselves a little room to bump them up when needed in the future.
Her 2nd treatment was today, Sept. 16 and so far she is fine. We also saw Dr. Patrick Mahaney for a consult on holistic supplements we can provide to Maggie. Finally, since the chemo drugs will reduce Maggie’s natural immunity, we need to monitor her white blood cell count, so it requires a quick vet visit between treatments to make sure it stays within an acceptable range.
We will update as Maggie moves through her treatments, but I’m hoping to have nothing to report! We will report on our conversation with Dr. Maheny and I have a post planned on safety measures for a dog (and family) undergoing chemotherapy treatments. Thanks to all of you who have written us and sent your best wishes and prayers for our sweet Maggie May – they have certainly helped.