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

Low Dose Chemotherapy and Cancer

Updated: May 15th, 2024

Over the last few years, there has been much work in attempting to improve canine cancer treatment.

One strategy has been to use lower, continuous doses of oral chemotherapy drugs.  The goal in this is to lessen chemotherapy toxicity, reduce trips to the oncologist for IV injections (the medications are pills), and hopefully gaining life span and life quality gains.

This is approach is called metronomic chemotherapy.  Here, lower doses of drugs such as cyclophosphamide and piroxicam have been used with some success.  Initial trials show promise with cancers such as hemangiosarcoma and soft tissue sarcomas.

One of the ways this treatment works is by acting on an enzyme found in higher levels in some cancers, called COX-2.  This enzyme is “turned on” during inflammation. When this enzyme is activated, cancerous cells are able to suppress the immune system and create new blood vessels to feed tumors (angiogenesis).

Many think of metronomic chemotherapy as an attack against angiogenesis.

Perhaps most importantly however, when COX-2 is active, cancer cells are able to avoid apoptosis.  Apoptosis is a naturally occurring process which is coded for in normal body cell genes.  When these cells become pre-cancerous, damaged, old or infected, the apoptosis genes create what is called “cell suicide”.  Apoptosis is the name for this genetically programmed cell suicide directed towards clearing out unwanted cells.

Cox-2 has been found in a variety of dog cancers, such as transitional cell carcinoma, some mammary carcinomas, prostate carcinoma, squamous cell carcinoma, and carcinomas of the nasal and intestinal lining.

One of the common metronomic chemotherapy drugs is piroxicam.  This drug is able to help block the effects of the COX-2 enzyme.

There are plant-derived substances that are capable of having similar effects on COX-2.  These include luteolin, apigenin, and curcumin (among others).  It was for this reason that these constituents were included in the Apocaps formulation.

Metronomic chemotherapy, and the use of substances that fight COX-2,  are still in their early stages, and has not yet had large scale studies completed to assess its effectiveness on a wide variety of cancers.  However, oncologists are using these promising strategies today for canine cancers.


Dr D



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  1. Katina on September 23, 2013 at 1:38 pm

    What are your thoughts about using metronomics with a 13 yr old lab mix with Hemangiosarcoma liver cancer and accompanying kialis filling her belly and requiring weekly draining? Too far gone?

  2. Kevin Cwirla on March 16, 2013 at 11:54 am

    HI, my dog Drake was diagnosed originally with synovial sarcoma, and has his third digit in his right front paw amputated. He is currentky om meloxicam, and and recieving metronomic chemotherapy with cyclophosmide. Its been the first month since he has been on the metronomic chemotherapy and all is going well. I also give him senior dog vitamins, cranberry , billberry, lutien, glucosimine/chonoditrin everyday. I have been feeding him science diet ld dry dog food with a can of science diet canned dog food. His bowel movements have been good and urination has also been normal. Drake is on keppra for seizures which is working great and is also on thyroxin. You would never know if yo met Drake , he is happy and active. He seems very happy. I hope he will be around for a while-hope a few more years, right now I just enjoy every moment I have with him. I hope he can beat this. The oncologist aslo informed me that his cancer may be hystocitis, hopefully spell correctly. The oncologist at U of Illinois said that this cancer is typically aggressive but has not been behaving that way in Drake. I can only hope that his treatment and care will keep this cancer from spreading or better yet go into remission.

    • Dr. Demian Dressler on March 19, 2013 at 5:06 pm

      Dear Kevin
      I am glad the treatments are working so far!
      Best of luck
      Dr D

  3. roberta Weiss on April 5, 2012 at 5:54 am

    wrote my problem please answer

  4. Linda Joseph on April 5, 2012 at 3:12 am

    Dear Dr. Dressler,
    Our almost 14 year old Bichon was diagnosed with Osteosarcoma in February. She had her left rear leg amputated. We have heard how uncommon it is for a Bichon to develop this cancer. The distemper and rabies vaccinations that my dog received prior to limping make me suspect of their involvement. The surgeon didn’t think this was the case. What do you think?
    Fast forward, a month after the amputation we consulted with a Vet Oncologist. He mentioned chemo treatment with Doxirubricin. We were advocating for Carboplatin. She received a 55mg dose of Carboplatin. Our dog was only 7.4 lbs at the time. We told the Oncologist about our dog’s sensitive nature. She reacted to Distemper shots in the past and being premedicated with Benadryl. She went lame after a Rabies vaccine when she was younger. The Oncologist did not send us home with any anti-vommiting meds or a scrip for one. Eight hours after the Carboplatin, she began vommiting. She continued to go downhill by not eating, drinking very little, ( we were giving her water through an eyedropper every hour or so). They still did not want to give any meds. Finally, 48 hours later, they said to get Cerenia. The vet’s office didn’t have it, so they substituted Metroclopramide. She continued to vomit. Only this time she vomited up some pink particles which looked like blood. At that point, the vet oncologist tech told us to get her a shot of Cerenia. After she began vomiting bile and she had an audible noise on exhalation. We took her to the animal emergency two more times. The last time she was admitted and kept for 4 days. She was diagnosed with Ileus and Gastroenteritis. We don’t want her to have another dose of Carboplatin. We purchased all your supplements and a product called NuVet Plus. I am wondering when we should begin providing the supplements again. She is a picky eater. Her weight is now at 6.4. I also would like to know if I should include the NuVet Plus with your recommended supplements. We are going to see a vet that does Accupuncture and uses Chinese Herbs. A couple of questions remain: 1.) Was the dose of Carboplatin too high for our dog’s sensitive nature and low body weight? 2.) Would it have been prudent to have sent us home with anti-vomiting meds, or to have given her a shot of Cerenia with the Carboplatin? 3.) Should Cerenia have been introduced sooner than 48 hours? Our dog was so distressed, I didn’t think she was going to make it. Luckily with the IV meds and treatment at the emergency hospital, she pulled through. If you wouldn’t mind answering my questions and offering a suggestion for the next step, it would be greatly appreciated.

    • Dr. Demian Dressler on April 12, 2012 at 2:20 pm

      Dear Linda
      I am sorry to hear about your little one.
      I am not sure if the rabies vaccine is connected with the bone cancer- I doubt it as a direct cause and effect. Don’t use Nu Vet with either chemo or Apocaps as the supplement is not designed for cancer and there are many competing mechanisms going on between the chemo/apocaps strategy and the stuff in Nu Vet (interference).
      I am sorry I cannot say if the dose of the carbo was too high or not, nor what was done during the administration. I don’t know.
      Many oncologists do send owners with a home kit for GI side effects of chemo meds, but not all. I think it is a good idea to do so. There is a lot of variation there depending on philosophy and I don’t think it is wrong per se to not give Cerenia with chemo and only use it if needed.
      It sounds like you are feeling pain (and rightly so) for her pain, and this is very understandable. This is very, very hard.
      Have you done a treatment plan analysis?
      The Guide goes into detail about how to make decisions that work for you and your dog.
      I hope this helps
      Dr D

  5. roberta weiss on April 2, 2012 at 10:36 am

    I think I would like to explain more clearly as to the problem my Yorkie has. She has spindle cell secoma. The mass is around her pelvis and we were told by 2 Dr’s that even if they operate they would have to amputate her leg and part of her hip, it would only come back in a different area. Another suggestion was radiation. It would be for 15 days and we would have to take her home on the weekends and being her back the next week for more treatments. In the end it would only give her a few extra months. My vet has suggested metronomic Chemo. The side effects are not good and he said even if she did not have the side effects, she would only go a few months . At this point she is happy and not complaining. Missy is 10 years old. Please give me your opion as to how much longer she would have with the treatment?. The most important thing is for her to have quality of life for as long as she has left. Thank you Roberta

    • Dr. Demian Dressler on April 12, 2012 at 3:03 pm

      Dear Roberta,
      Sorry about your little one.
      AS to longevity, I cannot make that call on the internet. This is a question for someone (your vet) with hands on the dog.
      I would be talking to your vet about the dog cancer diet, apocaps, neoplasene, IV vit c with or without vit k3, and beta glucans as a start. Also possibly low dose Palladia. Have you read the guide?
      I hope this helps
      Dr D

  6. roberta weiss on April 2, 2012 at 3:56 am

    My Yorkies has spindle cell sarcoma. She has a tumor mass around her back leg. Surgery will not cure it and she will loose her back let and part of her hip. We spoke of radiation and she would have to be away from home for three weeks and 5 days of the week she would have to be put to sleep. With doing nothing, and she is in no pain, we give her medication for the infllamation and pain , they gave us 6 months. We are not looking into metronomic Chemo. How much longer would this treatment give her? and what is the quality of life she will have? Thank you for you help Roberta

  7. Camimor on March 27, 2012 at 7:06 am

    My 9 year old Australian Cattle Dog had a huge mammary tumor removed Feb. 2010. She did not undergo chemo after surgery. Recently mets were found in her lungs which doubled in size and number in a month. My vet and many consulting oncologists are urging us to try metronomic therapy beginning with cyclophosphamide and piroxicam and then if she tolerates that adding in Palladia. I know it is a shot in the dark and I am worried about side effects since she is so happy for now. I have the Guide on kindle and ordered the hardcopy. I asked my vet about supportive meds/diet/suppplements… but is there something specific for her situation that I should be giving her,feeding her or be aware of removing from her regimen. She has also had a splenectomy for benign tumor. She takes Prozac,Trazodone, Duralactin and Dasuquin with MSM. Thank you so much, She may begin the treatment end of this week.

  8. Lisa on January 24, 2012 at 8:46 am

    Dr Dressler,
    Maxwell, my 8 ear old Pug was diagnosed with grade III spindle cell sarcoma in the right rear hock on 5/16/11. Because he was in pain I went ahead with the amputation which he recovered from remarkably fast from my perspective. I also agreed to “preventative” chemo because this cancer was graded so high. he did reasonably well with it but had low white counts usually on day 10 after the chemo. We handled that with Clavamox and he did well. Maxwell woke up one morning with a terrible cough. I brought him to the vet/oncologist, they did an x-ray and discovered he had a tumor in his lung. The vet/oncologist suggested changing the chemo that he was getting to Carboplatin which I agreed to. He receive 2 treatments of that and it was determined that there was no more that could be done for him because the tumor was growing so fast. After the shock of that I became very angry and went online and found your diet. I ended up purchasing your book and I am NOW and educated guardian. We are seen a different oncologist now and while his prognosis is unknown at this point, Max has surpassed what we were told to expect. I have changed his diet and he is getting Apocaps, K9 Immunity, and Palladia. He is a happy little dog with a LOT of fight left in him.
    Here’s my question…of the cancers listed in your book, i don’t see Spindle Cell Sarcoma in your section or Dr Ettingers. Is it the same as another cancer like Mast Cell? Can you please guide me to where I might be able to find information about this in your book?
    Both Max and I thank you for all you do for guardians and their “kids”!

    • Dr. Demian Dressler on January 25, 2012 at 11:43 am

      Dear Lisa,
      I am glad you are on a good road to pet advocacy!!
      Spindle cell tumors fit in the class of soft tissue sarcomas in the book- see page 366 second edition.


  9. Sharon Sleighter on January 13, 2012 at 4:58 am

    My 12 year old boxer female started metronomic chemotherapy, cyclophosphamide and piroxicam, two weeks ago after having an anal sac tumor (adenocarcinoma) removed. Given her age, she is not a good candidate for injectable chemotherapy, so we decided to give this a go. She is doing fabulous so far. We have everything crossed that the will help us slow the growth of any new tumors (we did not get clean margins on the tumor that was removed). As a boxer lover, I am so happy we have dedicated vets out there working on better treatment options for our fur kids. Thank you.

    • Dr. Demian Dressler on January 18, 2012 at 3:14 pm


  10. Ivan Dryer on December 13, 2011 at 4:52 pm

    Dear Dr. Dressler,

    My 14 y-o Cocker has been on metronomic chemo with cytoxan and metacam for nearly 2 months, and the sarcoma has slowed its growth. We are hoping it stops completely and even shrinks. Meanwhile, he continues on ApoCaps and K-9 Immunity, etc.

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