After a series of emails back and forth with the oncologists (Dr. Maria Camps and Dr. Andrea Smith, both at the Animal Medical Center), I have a lot more information.  I'm including it below in the question and answer format that matches our emails.  In my regular forum post and blog about Griffin's Journey, I explain the course of treatment I have chosen to follow for Griffin.

1. What is your success rate with the 11 rounds of chemo versus 6 rounds?  If no hard data is available, what is your anecdotal evidence?  Anecdotally, we have had more patients with survival times over a year and closer to 2 years, who received more chemotherapy, compared to the reported 9-12 months seen with carboplatin alone or doxorubicin alone. But again, this is just one small population and studies looking at combination protocols have not shown a significant difference between single agent and combination protocols. ​Again, this is just our experience and other oncologists may have had other experiences. 

2. What is your success rate with alternating agents versus single agent Carboplatin?  Are there scenarios when you recommend single-agent treatments instead of alternating? We feel completely comfortable recommending single agent carboplatin or single agent doxorubicin, especially in cases where using a combination protocol is not feasibly possible for the family; single agent therapy is the standard of care. We like to offer the combination protocol as an option for those who don't feel comfortable stopping treatment after just 5 or 6 treatments, and again in our experience, those patients sometimes do just a little bit better. ​

3. How often have you stopped treatments due to side effects from Carboplatin?  from Doxorubicin? Discontinuation of treatment due to side effects is very rare, with either treatment (less than 5%). Additionally, side effects are completely patient dependent and some dogs often tolerate one drug better than another. 70% of our patients won't have any side effects from either chemo, 30% will need supportive care at home, while 10% may need in-hospital aggressive supportive care.  In our experience, carboplatin tends to cause more bone marrow suppression while doxorubibin tends to cause more GI side effects. 

4. What is the rationale for waiting 4 weeks for the next round after Carboplatin when the standard seems to be 3 weeks? The dosing for carboplatin is every 3-4 weeks, and again is somewhat oncologist dependent. We generally choose to administer the highest recommended dose given every 4 weeks in our patients as it tends to be tolerated better and results in less treatment delays (sometimes the bone marrow doesn't have enough time to recover in 3 weeks). 

5. If I could do only 5-6 rounds of chemo, would you still recommend alternating drugs or would you recommend using Carboplatin only? ​We would recommend doing single agent carboplatin or doxorubicin in that case, since that the standard of care.  We would advise to pursue either 4-6 carbo doses (gold standard therapy with preference to 6 doses).  If you choose to alternate for more than 6 doses, we'd recommend giving 4-6 carbo and 4-5 doxo treatments.

6. If I wanted to pursue the Yale vaccine option and could afford only 6 rounds of chemo, would you suggest completing all chemo first and then administering the vaccine or pausing chemo after 4 rounds, administering the vaccine, and then completing the last 2 rounds of chemo?  ​We would recommend finishing the protocol and not interrupting therapy, as we know that chemotherapy is beneficial for this disease. Since the impact of the vaccine is unknown, we would rather he complete the standard of care therapy without interruption, before pursuing an experimental treatment.

7. What about continuing with additional rounds of chemo after completing 6 rounds and then the vaccine? Since chemotherapy works on the microscopic disease setting and we are under the assumption that the cancer will progress when we stop the chemo (that's why we recommend continuing it), we wouldn't advise stopping it for a few months and then re-starting it for fear that it won't be as effective.  However, we could revisit that option in January if Griffin continues to maintain a full remission.

8. Besides the chemotherapy, what additional actions are recommended? We recommend repeating chest x-rays every 3-4 months and repeating abdominal ultrasound every 6-12 months.