How to Know What the Best Chemotherapy Treatment Is for Your Dog

June 25, 2021
A siberian husky receiving an IV fluid

We know you want to do what’s best for your pet—and what’s best for your wallet. Treatments for cancer are certainly not cheap, but we’re going to cover the different chemotherapy protocols and how you can find out the best one for you and your pet.

In our last post, we covered the different methods of treatment and the pros and cons of each. We tend to lean in the direction that chemotherapy will be the best option to treat your pet. As with many treatment options, there are multiple different routes that each treatment can go in.

We know you want to do what’s best for your pet—and what’s best for your wallet. Treatments for cancer are certainly not cheap, but we’re going to cover the different chemotherapy protocols and how you can find out the best one for you and your pet.

Why chemotherapy is usually the best option

Chemotherapy treatment is typically the best route for dogs with lymphoma, as it gives them the highest chance of going into remission. Lymphoma usually affects multiple places in the body rather than staying localized, so by putting a treatment in action that requires the medicine to appear throughout the body, the best results are achieved.

Dogs also react totally differently to chemotherapy than humans do. Their bodies are more equipped to handle the medicine than ours are, which is a good thing. As their treatment goes on, they usually only have a few slight side effects. These can include loss of appetite, nausea, etc.

Your veterinary oncologist will work to make sure your pet experiences as few symptoms as possible.


Different protocols

There are a few different routes that chemotherapy treatment for lymphoma can take, this depends both on the type and the intensity of the cancer. The treatment will depend on what your dog needs as well as what you can afford. Every treatment plan has its own benefits and costs. Deciding what the best option is for you and your pet is a hard decision to make, so we're here to ease some of your confusion and list the different options you could choose.

Prednisone

Prednisone is a steroid drug that is commonly given to dogs as an anti-inflammatory medicine, sometimes for allergies or itchiness. The drug has many uses, including boosting the immune system for immuno-deficient patients.

Because Prednisone is able to work with immune systems, it has the ability to also treat Lymphoma patients. The medicine has a 50% response rate in Lymphoma patients when they complete treatments. There are a few downsides in choosing Prednisone as your primary treatment. If this is the first line of defense at an early diagnosis of lymphoma it could inhibit future understanding of the development of your dog’s cancer. This steroid interacts with the cells and makes them appear differently because of that interaction. Another is that it is harder to start a chemotherapy regimen after treatment with Prednisone. And because it is a steroid medicine they would need to be weaned off the medicine.¹

But treating with Prednisone alone doesn’t have as strong of response rates as a more in-depth chemotherapy treatment would. The average length of remission from a prednisone treatment alone is 2-3 months. Still, this is significantly better than the average survival rate of a Lymphoma patient with no treatment, which is one month.

A Prednisone treatment can be the most cost-effective because it is just a common steroid drug. The time frame for this particular treatment depends on the dog and their Lymphoma’s intensity.²

Prednisolone + Chlorambucil

Prednisolone is similar to Prednisone in more than just spelling. They are effectively doing the same thing with the difference of one step within the body. When Prednisone is given to the patient, their liver works to process the medicine and turn it into Prednisolone. By giving your pet Prednisolone to begin with, you cut out that middle step within the body's process.⁴

Chlorambucil is an alkylating drug that interacts with the production of cancerous DNA and RNA strands and suppresses antibody production.³

When these two drugs are partnered together they are effective in treating low-grade T-zone cell lymphoma. They work together to provide two different attacks on the cancerous cells and create a stronger chance for remission.

Doxorubicin

Doxorubicin is one of the more common single-agent chemotherapy drugs; the nickname for this treatment is DOX. This medicine works well in a combination treatment, like CHOP and its counterparts, but it can also be seen as a standalone medicine when a single-agent chemotherapy protocol is chosen—either for cost efficiency or because it is the best option for that particular case.

DOX as a single agent treatment is effective in treating B-cell lymphoma, though it is significantly more likely to bring a dog into remission if combined with another chemotherapy drug during the treatment. The likelihood of remission in a single agent DOX treatment is 74-88% and remission can last anywhere between 4-6 months.

When using a DOX treatment, it’s usually given once every 3 weeks for a total of 5-6 treatments.5 While treatment with a single agent chemotherapy is naturally going to be less costly, be sure to consider if the difference in remission time is worth the cost.

CCNU

Another commonly used single-agent chemotherapy medicine, as well as one that works great in combination treatments is CCNU. CCNU, also called Lomustine, is an alkalizing agent designed to cause trouble to the dog’s DNA and RNA, stopping them from transcription and replication respectively. This is usually given at the beginning of treatment to assist in the efficiency of the chemotherapy, similar to L-asparaginase.

CCNU is a common medicine chosen to combat initial cases of T-cell lymphoma. It is also one of the go-tos of rescue protocols to give at the beginning of relapse because it is so commonly effective.

CCNU is helpful for treating cutaneous lymphoma specifically, having roughly a 80-90% response rate in dogs that use it as part of their treatment protocol, with 26% of pets getting to complete remission.6

CHOP

For many vets treating lymphoma, this protocol is considered the “Gold Standard”—the one that they know will most likely have the best response and remission times. It’s the best for treating multicentric lymphoma, which is the most commonly found form.

CHOP consists of 4 different chemotherapy drugs. Cyclophosphamide, Doxorubicin Hydrochloride (sometimes called Hydroxydaunomycin), Vincristine sulfate (brand name Oncovin), and Prednisone. Each of those different drugs works to attack cancer cells in a different way.

The CHOP protocol is effective for the initial treatment of multicentric, B- or T-cell lymphoma.

This treatment typically goes over the course of 15-17 weeks, or up to 25 weeks depending on the stage of your dog’s cancer. Your dog will be alternated between the medicines so that the cancer cells don’t develop a resistance to any of the drugs.⁷

L-CHOP

Although CHOP is already a very strong protocol, in certain situations it can make sense to add to it. L-CHOP is a protocol that follows the same pattern as CHOP with the addition of L-asparaginase—which is given as an injection.

Asparaginase is an enzyme that healthy cells produce naturally. Cancerous cells need much more of it than a healthy cell and they cannot produce it themselves. The cancerous cells die when they run out of that enzyme. Adding the L-asparaginase enzyme shuts down the production of the needed enzyme and gradually causes cancerous cells to run out of fuel and die off.

The addition of L-asparaginase is typically held off for treatment of a relapsed patient with T-cell lymphoma, although it can be added to an initial treatment as it is commonly included as part of a rescue protocol.8

This is added towards the beginning of a CHOP protocol and typically lasts the same number of weeks, between 15-17.

COP

COP protocol is similar to the CHOP protocol in that they both feature a multiagent chemotherapy treatment and most of the same drugs, with the exception of Doxorubicin Hydrochloride. This particular protocol is most often one that can be given in the safety and comfort of your own home, with just a few regular visits to the vet’s office for some injected medicines.⁹

The COP protocol is more beneficial for treatment for B-cell lymphoma types. When the COP treatment is given to B-cell lymphoma patients they are expected to be in treatment for up to 12 months and many achieve a remission time of around 6-9 months on average.¹⁰

While the COP protocol is slightly cheaper than CHOP, the remission length and rates reflect the difference on average.

LOPP

LOPP is a high-grade T-cell lymphoma equivalent of the CHOP protocol. It has a few of the same drugs: vincristine (O), and Prednisolone (P). LOPP runs on a similar multi-agent process that CHOP protocol is known for and targets the harder to treat high-grade T-cell lymphoma.

LOPP treatment uses a plan using Lomustine (CCNU), Vincristine, Prednisolone, and Procarbazine. These four medicines work together with an amazing response rate and lead to a low toxicity level from the medicine. This is one of the most effective treatments for T-cell lymphomas, a cancer that otherwise would be difficult to treat.


Relapse treatments

When a dog’s remission ends they often have to go into a new treatment plan, although there are times when a repeat of the same system that got them into their remission is safe to reuse. A patient who participated in the CHOP protocol to get into their first remission, for example, would be a good candidate to restart the CHOP treatment if they relapsed after a minimum of two months. In this instance, the chance of them achieving a second remission with the same treatment plan is very possible.

For other dogs, there are a few options that can extend their life through a second remission.

MOPP

The MOPP protocol is one of the most common multi-agent chemotherapy treatments given in a case of a relapse as a rescue protocol. It consists of a combination of two injectable drugs and two oral drugs. The combination of chemotherapy drugs for this protocol consists of Mustargen, Vincristine, Prednisone, and Procarbazine. Mustargen and Vincristine are the injectable drugs that are given on day one of the process and repeated again after 7 days. Prednisone and Procarbazine are given orally at home on day one and given regularly for 14 days. After that cycle of 14 days is completed, there is a 7 day rest period.

When this program is put into action the 3-week cycles are repeated as necessary; in an effort to achieve complete remission it takes around 6-8 cycles. This totals out to about 4.5-6 months of active treatment time.11 In the case of a relapse the chances of achieving a second complete remission is about 31% and it can last an average of 2 months.¹²

Dacarbazine + DOX (B-cell) or + CCNU (T-cell)

Dacarbazine was originally used in treating human Lymphoma cases. After identifying its usefulness to treat canine lymphoma and verifying that it was completely safe to use on dogs, it was found to be more beneficial to lingering cases.

Dacarbazine, or DTIC in short form, has been discovered to be one of the best medicines to use in a rescue protocol because it is not commonly used in the initial multidrug treatment. This newness is useful to rescue protocols because the cancer cells have usually developed resistance to the old drugs, rendering them practically useless.

By pairing this medicine with either DOX or CCNU, the treatment plan can target B-cell and T-cell lymphomas more directly and effectively.¹³


Personalized Prediction Profile

ImpriMed has developed their lab to go further than just identifying the type of lymphoma that your pet has. Our systems have the added option of our Personalized Prediction Profile, which includes a CHOP response prediction.

When our AI system processes through up to 300 different chemotherapy medicine combinations, we develop a chart that predicts how the treatment will impact your dog, as well as their predicted time frame of relapse.

This prediction allows us to inform both you and your vet what the best route of action would be, as well as what the outcomes are likely to be based on cellular response to our tests.

Ask your doctor if they are a part of our program or find an oncologist near you that is already involved.

Learn how to get your vet involved with our program.