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Featuring Demian Dressler, DVM and Sue Ettinger, DVM, Dip. ACVIM (Oncology), authors of The Dog Cancer Survival Guide

Metronomic Chemotherapy

Updated: May 15th, 2024

Traditional chemotherapy is moving in a new direction.

In the past, chemotherapy used a strategy called Maximum Tolerated Dose (MTD).  Simply put, this is giving the highest dose a patient can handle, ideally without an unacceptable risk of side effects.

The reason this strategy is used in cancer medicine is that the drugs we have available rarely cure a dog of cancer.

Therefore, to extend a four legged family member’s life, we want to try to kill as many cancer cells as we can.  When we use most chemotherapy drugs, however, they do not restrict their actions to cancer cells.

In other words, they are not truly selective.  They sometimes exert actions on the body cells, which can produce the side effects we wish to avoid.  These side effects can impact a dog’s quality of life, as well as yours.

This is the trade-off that is an occasional reality of dealing with these drugs.

For this reason, a detailed portion of The Dog Cancer Survival Guide is devoted to ways you can decrease the odds of chemo side effects in your dog.

Recently, there has been another strategy in helping dogs using chemotherapy.  This is called metronomic chemotherapy.

The goal of this approach is to try to slow the recurrence of the tumor, or slow tumor spread.

The way this is accomplished is by affecting the blood vessels that feed the tumor.  Metronomic chemotherapy uses lower doses than MTD’s, and also combines drugs that have anti inflammatory effects.

These drugs act on the lining of new blood vessels to help shrink the vessels.  We cut the supply of oxygen, sugar and nutrients to the tumor, and hopefully slow tumor spread.

Probably the most common combo includes cyclophosphamide and piroxicam, but this varies depending on the oncologist’s preference and the cancer.

It is interesting to note that the apoptogens in Apocaps have many of the same affects as these anti inflammatory drugs. Read more here, and here.

If you would like to consider this chemotherapy approach for your dog, it would be prudent to seek an oncologist’s input.

For more on strategies to help your dog fight cancer, see the Dog Cancer Survival Guide.


Dr D

Leave a Comment

  1. salaha on January 3, 2013 at 11:55 am

    Dear Dr. Dressler,

    I contacted you 2 years ago so as to get your opinion on cancer medications for my dog.

    He had just undergone cancer surgery, and two types of cancerous growths were found and successfully removed (1) squamous cell carcinoma in his mouth and (2) intestinal adenocarcinoma with evidence of vascular invasion. The surgeon recommended we have follow-up chemotherapy. Eventually metronomic therapy was recommended using a combination of peroxicam and cyclophosamide, for an initial period of 9-12 months, which was subsequently extended.

    So here we are 2 years later and my dog (who will be 14 years old this coming April) is still on this regimen. Unfortunately the peroxicam is taking a toll on his intestine. Remarkably however, his bloodwork (CBC plus T4) have all come back negative. And his IBD is under control. But age and arthritis are now also coming into play. He is straining to get up and down, and getting into the car. For the past week we have been giving him ‘Zeel’ and hope to see some improvement soon.

    My dog is as alert and inquisitive as ever, has a great appetite, a very positive attitude, loves to go for walks, and is an all around wonderful buddy.

    So the question I have is, when will he be considered ‘cancer free,’ so that we can stop his metronomic chemotherapy?

    I have scoured the internet for the answer to this question, and have contacted 2 local cancer vets and the State Vet School. As yet I have been unable to get an answer.

    I would appreciate hearing your thoughts on this subject.

    P.S., appreciate getting your “Dog Cancer News” updates. They have provided a great deal of insightful information.

    • Dr. Demian Dressler on January 29, 2013 at 5:48 pm

      Dear Salaha,
      that’s a good question that we really don’t have an answer for in veterinary medicine. The problem is the possibility that the steps you are taking are keeping cancer cells at bay. Truthfully we have to guess with this, and it becomes nothing more than a judgement call when we make the decision to stop the meds. One option is perhaps half dose metronomic. Perhaps you could discuss this with your oncologist?
      Dr D

  2. Lisa on December 21, 2011 at 6:12 am

    My dog is now 2 wks. post-op amputation of his left front leg due to fibrosarcoma in his elbow. I thought we were in the clear, however, just received call from vet stating they recommend chemo for any possible metastases. I want to go the metronomic route for soft tissue sarcomas, but need information to take with me to the oncologist. Could you please direct me toward recent studies with protocol for chemo for fibrosarcomas. Thank you.
    Lisa and Max

  3. Christine on June 7, 2011 at 8:40 am

    Hi Dr.
    One of my dogs was just diagnosed with fibrosarcoma on his thigh. One of the treatment options is oral metronomic chemotherapy. Could you explain this to me in a little more detail?
    Scooby’s Mom

  4. Nicole Thome on July 21, 2010 at 9:06 am

    Hi Dr Dressler,
    I was wondering what your thought is on long-term use of metronomic chemo? The benefits and/or risk with keeping a dog on it long term.

    I was told that …the reason many oncos decide to stop the treatments at a certain pont in the protocol is that there’s no benefit to giving more treatments after that. If a dog is going to stay in remission, the treatments up to then are enough to get the dog to that point. If he/she’s going to come out of remission, he will whether more treatments are given or not.

    Nicole (Mom to OS dog, Daggit)

  5. Jo on July 11, 2010 at 7:50 am

    Dr D, , Please help… my beautiful 7 yr old collie Leah, has lymphoma. She had chemo last year and I have had her on full spectrum cancer care for 7 mths. Her remission lasted 10 mths and now the chemo isn’t working, she is drug resistant, her nodes keep going down and coming back up again. After reading your blog on metronomics, I asked my oncologist if we can try this for Leah, but she says that they are no longer using cyclophosphamide as it causes severe gastro problems. I have not been able to find any evidence to back up her claim and believe you are still using this drug in the US. Do you know if this is true? Please, please help, I am running out of options and I can’t bear to loose my lovely little girl.
    Jo (UK)

  6. Leslie D Ufford on June 30, 2010 at 12:42 pm

    My dog has been doing well on cytoxin/piroxicam for a year but his urinalyis yesterday showed microscopic hematuria. He is now off the cytoxin and we will do another urinalysis in a month. He also had xrays and u/s yesterday and there is no current sign of mets. I hate having to change his protocol as he has done so well, He is also taking fish oil, Onco Support powder, Carnivora, and Apigenan. Would adding Apocaps help to replace the antiangiogenic action of the cytoxin and, if I start him on that, should I drop the Apigenan caps? He also gets two homeopathic remedies and I do accupressure on him.

  7. Brad J. on June 25, 2010 at 6:18 pm

    Hello Doc Dressler, i have a 7 yr old beagle /lab mix (Bear) with lymphoma and AIHA and has been on chemo treatments for about 8 weeks. He went into remission but recently has some skin lesions again and had elpsar this week which has dried up most of the lesions and is scheduled for ccnu next week. The adriamycin didn’t help evidently because he started developing lesions a few days after treatment. He doesn’t have a lot of lesions like the first time or lymph node swelling but i’m concerned because it will probably get worse but i understand ccnu is for skin presentations. He’s a white dog and is also on prednisone 20mg and cylosporine 2x a day for auto immune disease that he has had since december 09 and after stopping the pred he developed the skin lesions and 2 lymph node swellings, diagnosed as lymphoma. Overall he’s done well but i know he’s up against it. He had vincristine and elspar the next day after he was crashing, that was a miracle combo and he went into remission and has had vin/cytoxan and adriamycin after that. Sorry for the long story, i know this is a strange presentation, a dog with AIHA and lymphoma. He’s been a relatively healthy dog, appetites good and he made it back from near death and i’m wondering if anyone has any suggestions.I haven’t received much info on what i can do and i just wonder if there are any new treatments and if ccnu is the best option. Also i am supplementing with milk thistle, turmeric and omegas but not sure if i should use immune boosters because of the AIHA. Any help is greatly appreciated, Bear is like a son to me and i want to give him every chance. You know more than most so i thought i’d ask for any info. Thank you very much.
    Brad (

  8. Gina on June 23, 2010 at 5:53 am

    Our shi tzu, Tiger, was diagnosed with cancer in February 2009 and began metronomic chemo shortly afterwards. He takes it once a day.

    We also supplement his diet with turmeric, garlic, liquid vitamin C, honey (antiseptic) and peanut butter (to get the pills down and keep his weight up).

    And prayers. Many prayers from so many who care.

    Tiger’s doctors had given him a few months — today, Tiger is happy and running and in no pain at all.

    We took him off the chemo two months ago because his white blood cell counts were down (chemo does that), and now we’re having problems elevating them.

    But all in all, we’ve been so pleased.

  9. Nicole Thome on June 23, 2010 at 5:50 am

    Dr. D … thanks for posting about this! It’s great to see more oncology vets starting to use Metronomic Protocol. My girl, Daggit, was on MP for 6-months and tolerated it very well (she’s still going strong 10-months post-dx osteosarcoma). I wouldn’t hesitate to put her back on it if she were to develop lung mets (God forbid). Her treatment included:
    – Cyclophoshamide (Cytoxan): 25 mg; once in the morning every other day
    – Deramaxx (NSAID): 25 mg
    – Doxycycline: 100 mg; anti-biotic
    – Lasix (furosemide): This is a diuretic. Cytoxan commonly causes UTI and/or hemorrhagic cystitis. I cannot stress ENOUGH the importance of adding this to the protocol — particularly in females in which the bladder issues seem to be more common.

    Another benefit of MP or “low dose chemo” is cost — it’s much more affordable than IV chemo.

    Good luck to all our cancer babies out there!

  10. Spirit Jerry, Jim & Rene on June 21, 2010 at 6:18 am

    Hey Dr. D, we just posted about a new version of metronomic chemo that one of our favorite oncos is doing in Santa Fe New Mexico: Metronomic Protocol: a Primer for Pawrents.”

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