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

Dr. Sue’s Recommended Tests for Osteosarcoma Diagnosis and Work up (pre-surgical biopsy optional)

Updated: April 15th, 2019

As I discussed in the previous blog, the first sign of osteosarcoma (OSA) that a pet Guardian sees is usually limping, or refusing to put weight on the leg involved. This is because bone tumors hurt, especially when the bone bears weight — so your dog will be lame or will limp. You may see swelling in the area of the tumor, but it can be hard to see the mass, especially the ones higher on the leg or in dogs with a lot of fur.

Am I suggesting that every dog that suddenly limps has OSA? Clearly not, but if you have an at-risk dog (the large or giant breeds, including Great Danes, Saint Bernards, Irish Setters, Rottweilers, German Shepherds, Golden Retrievers, and Doberman Pinschers*), in the age-range risk (7 to  9 years of age, also 1.5 to 2 years of age), see your vet promptly. If your dog does not respond to pain medications and rest within a week, be sure to get x-rays.

(*In my last blog, I was reminded me to include Greyhounds. Thanks to my readers for pointing out I had forgotten to include this breed.)

If osteosarcoma is suspected, testing can get complicated (and expensive). Here are the tests that you will likely be asked to consider — and my advice about whether to do them or not.

Limb X-rays: Mandatory

Ideally, all large and giant breed dogs with persistent and significant pain and lameness should be evaluated with radiographs (X-rays). Be prepared to have multiple view X-rays of the affected bone, which means more than one X-ray, taken from different angles. There are classic “textbook” things your vet will look for. There are certain classic bone changes seen with these tumors, including their typical “sunburst” appearance. And there are also a spectrum of other changes that can be seen on X-rays, from mostly bone lysis (or destruction) to mostly new bone proliferation.

Biopsy before surgery: Not Mandatory

Normally, I recommend confirming a cancer diagnosis with cytology or biopsy before performing a cancer surgery, but I make an exception if OSA is suspected. This is based on patient’s age, breed, history, physical exam, tumor location in the bone, and X-rays.  If all this point to OSA, I believe it is okay to proceed with amputation. (For amputation alternatives, check out the Guide).

Why proceed without a positive confirmation that the lesion is OSA? Because these aggressive bone lesions cannot be repaired, and they put the dog at risk for a serious and painful fracture. Amputation removes the destructive and painful process immediately. The leg will be submitted for biopsy at surgery, and this will allow tumor confirmation, and appropriate post-surgery treatments can be planned based on the biopsy report.

In other words, if OSA is highly suspected, you can stage the cancer (see below) and schedule a surgery, even if you do not yet have conclusive confirmation of cancer.

However, some owners are not certain if they want to treat OSA at all – they want to know for sure of the diagnosis before they decide how or whether to treat the cancer. In these cases, absolutely, a biopsy or bone aspirate should be performed first. (These tests are also discussed in the Guide.)

Chest X-rays (or CT scan): Mandatory

When you see bone lesions on X-rays, and OSA is suspected, chest X-rays should also be ordered and examined, ideally before amputation. That’s because OSA is agressive and tends to metastasize to the lungs. About ten percent of dogs with OSA have detectable spread to the lungs when they are diagnosed. Even though detectable spread to the lungs is uncommon, if you see it in your dog, the prognosis is significantly worse. In these cases, some guardians choose to reconsider the amputation and follow up chemotherapy and radiation treatments.

The simplest and most available imaging test is X-rays. Your vet should take three-view x-rays (not 2 views) of the chest cavity to look for lung metastasis. Chest CT scans are more accurate and can pick up these smaller lesions, but they aren’t available everywhere, require anesthesia, and are more expensive than X-rays.

Basic blood work and urine tests: Mandatory

Full blood panels, including a CBC and chemistry panel, should be run, and a urinalysis should also be performed.

Other Tests to Consider on a Case-by-CaseBasis

After lungs, the bones are the second most common site of metastasis, so if there are signs of pain or lameness in other areas of the body, they should be x-rayed to look for lesions. I do not typically recommend whole body x-rays, because of  the added cost (it takes a lot of X-rays in a big dog to get this done) and overall low chance a dog (about 6%) has bone metastasis at diagnosis.  If a dog is lame or painful in a second area, whole body x-rays or nuclear bone scan can be considered.

Regional lymph nodes should also be aspirated or biopsied to check for metastasis, even if they appear to be normal. Although lymph node spread is uncommon (occurring in less than 5% of dogs), its presence is a very negative prognostic factor; dogs with lymph node involvement live only two months, compared to eleven months. Knowing whether OSA has spread to the lymph nodes can help you make treatment decisions.

Metastasis to the abdominal organs is uncommon, so abdominal ultrasound is not routinely recommended. I will recommend one if there are blood work changes, if I think the bone tumor is a metastatic lesion and not the primary tumor, or for general health screening.  Abdominal ultrasounds are not painful or invasive, and can be used to evaluate the dog’s overall state of health before embarking on extensive and expensive treatments.

In the next blog, we will discuss amputation. It’s a really hard decision for most owners. I would love your input. If you’d like to contribute to my poll, please check out my FB page. (Please scroll down to the Jan. 23rd post.)


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  1. Ellen Venturella-Wilson on February 19, 2013 at 5:38 pm

    Our Charley, a chocolate Lab, was 2.5 years old when he was diagnosed with OS in his left proximal humerus and we chose amputation and 5 rounds of Carboplatin chemotherapy. Charley can do everything on 3 legs that he did on 4 — he counter-surfs, jumps and runs like the wind! Charley will celebrate his 28 Month Ampuversary on 2-28-13 and his 5th Birthday on 3-29-13, so miracles can and do happen!!! 🙂
    Here’s a link to a video of Charley playing in the snow at 12 weeks post amputation. It is amazing to watch!

    Hugs and chocolate Labby kisses,
    Ellen and Charley
    2 Year OS Warrior…and counting!

    • Dr. Susan Ettinger on February 22, 2013 at 6:50 pm

      I LOVE this video and watched the series. Loved him swimming too. May I share this on my FB page? They are great, and he is ADORABLE!!
      Thanks for sharing. Go Charlie!!!
      All my best, Dr Sue

  2. Carol Cure on February 19, 2013 at 10:04 am

    Our Golden Retriever, Sam, was diagnosed with OSA in his left front distal radius last September. It was a real shock because he had never indicated any pain or problem until the morning of the diagnosis when he refused to put weight on the leg. After taking him to our vet that very day, following x-rays, we were given the bad news. We did have a biopsy done before taking him to the Animal Cancer Center at CSU for treatment, where he had his left front leg amputated, including the shoulder bone. He also had a body scan that didn’t reveal any current metastasis. He has now finished 6 carboplatin chemo sessions, and continues to take 10 mg. of Piroxicam daily (which was begun when he was initially diagnosed). I understand this is supposed to suppress cancer cell growth. Do you have any experience with Piroxicam and what are your thoughts on it?

    • Dr. Susan Ettinger on February 24, 2013 at 9:58 am

      Hi Carol
      You and Sam are in great hands!! Piroxicam is a NSAID (pain med/anti-inflammatory) that also targets cancer blood vessels, called anti-angiogenesis. It is also used for bladder cancers and oral cancers such as squamous cell carcinomas.
      All my best, Dr Sue

  3. mckellygirl on February 19, 2013 at 8:54 am

    As I think back to what we did for my 9 1/2 y.o. Golden Retriever, we first thought he had an ACL injury. I was going to treat that with laser therapy, and before our first laser appointment, we did limb X-rays, and then I was called in to look at the X-rays and was told of a strong suspicion for osteosarcoma. We did chest X-rays the same day, which showed nothing. We did a needle aspiration which was inconclusive but still strongly suspicious for osteosarcoma. Bloodwork was certainly done, maybe twice (once before surger). Bailey underwent right hind limb amputation on June 14, 2011. I did not opt for chemo/radiation, but instead work to build up Bailey’s immune system with an anti-cancer home cooked diet and a various immune support supplements. I am happy to report that 20 months post op, Bailey continues to thrive and according to my vet does not act like a dog with cancer. Other than his tear ducts ceasing tear production last year, he is doing great and has fully adapted to life a tri-pawed and continues to be an inspiration to me.

    • Dr. Susan Ettinger on February 24, 2013 at 9:55 am

      Thanks for sharing Bailey’s story. May he continue to do well and bet the odds!!
      All my best, Dr Sue

  4. Glenda on February 19, 2013 at 7:19 am

    My Schultz had Bone cancer, The vet was treating him for Arthritis for awhile, then on Jan 9, 2012 he went to get up in the sofa and he feel back on his hind legs, he Immeditaley could not put his weight on the right rear leg, I called the vet and took him right in, as soon as they examined Schultz they ordered x rays, the doctor came and got me from the exam room where I was waiting and took me to a area to look and the xrays on the way to look they said it is not good, when we to llok at the xrays I could not believe what they were telling me, I was loosing my schultz and my heart felt like it was being torn out, the cancer was so bad I was told I had 2 choices I could put him down then or take him home and keep him as comfy as we could for whatever time we had left.. I chose to take my schultz home, On April 6, 2012 at 4:15 PM I had to let my Schultz go and I was devastated… I wish I had brought him back that day even of for just one more day! schultz was 14 years old. I miss him and I love him very very much, Then on May 29, 2012 I lost Mugger to cancer, although I do not know what type he had the vet said not all cancer will show up in the blood work. Mugger was 15 years old and he just refused to eat I tried everything to get him to eat but he just stopped and nothing I would do helped..Once again my heart was broken I had lost 2 of my babies. I miss them both so much.. I hate cancer!!

    • Dr. Susan Ettinger on February 24, 2013 at 9:53 am

      I am so sorry about Schultz and Mugger. You had a rough year. Remember all the good times shared through the years.
      Thinking of you, Dr Sue

  5. Ruth Dixon on February 19, 2013 at 3:19 am

    We had a beautiful Briard who succumbed to osteaosarcoma. She had a history of # leg with years of on-going complications from it so we didn’t notice her limp soon enough. We had her leg amputated from the shoulder down and she survived about seven months. But those seven months were wonderful. She ran like the wind on three legs. My only wish is that we had noticed the limp sooner and acted on it. I know of one other Briard with the same disease but his had progressed too far when diagnosed to be able to treat it. I know that with my new younger dog I will be vigilant about following up on any limp, no matter how mild.

    • Dr. Susan Ettinger on February 24, 2013 at 9:51 am

      Sorry about your dog. Try not to think about the “what-ifs” and focus on the wonderful 7 months. And now you have the info to be pro-active, if needed.
      Thanks for sharing.
      All my best, Dr Sue

  6. Andy Walker on February 19, 2013 at 3:10 am

    An intersting article though a little concerning. My dog (German Shepherd/Husky cross aged 6) recently underwent surgery and had a tumour removed along with some paw. She still limps very occasionally on the leg, or alternatively sometimes holds it off the floor (especially during cold weather). Therefore it would be reassuring to know if it is possible that this behaviour could be a normal post operation reaction and not necessarily cause for further concern as described by your article?

    • Dr. Susan Ettinger on February 24, 2013 at 9:25 am

      What you are describing could be the result of the paw surgery. If you have concerns, recheck with your vet and consider a leg X-ray.
      All my best, Dr Sue

  7. Spirit Jerry, Jim, Rene & Wyatt Ray Dawg on February 17, 2013 at 9:38 am

    Dr. Ettinger, the information here is spot-on, thank you for providing insight on these tests. The question of whether or not to do a bone biopsy comes up a lot at our Tripawds community, I know your perspective will help make this journey a lot easier for folks who are just starting out.

    • Dr. Susan Ettinger on February 24, 2013 at 9:17 am

      Thanks!! And thanks to Tripawds for being such a great resource and support group!
      All my best, Dr Sue

  8. Susan on February 12, 2013 at 7:53 pm

    We recently lost our beautiful Cooper to his battle with cancer. We did the amputation and one round of Chemo. I also found a study at the time online about giving the dog a maintenance dose of doxycycline daily to suppress the cancer cells that i. Shared with my Vet and she was game on trying it after reading the trials. We did this and our Cooper lived for a year and a half after his diagnosis, just making it to his 8th birthday this last January, longer than they initially told us he had maybe only months. Now our Vet is using this doxycycline therapy on two of her other patients. I’m so thankful to get that year and a half with him, he got to go on his neighborhood walks, chew on his Nyla bones and be a very happy lazy boy. I will cherish all those wonderful memories and hope that what my vet has learned through Cooper’s journey will help her other patients in the future.

    • Dr. Susan Ettinger on February 24, 2013 at 9:11 am

      I am so sorry about your loss of Cooper, and I thank you for sharing his story. Keep the memories close to your heart.
      All my best, Dr Sue

  9. Jane on February 12, 2013 at 11:14 am

    Thanks for an excellent article. Special thanks for noting that a biopsy is seldom recommended. I have heard of several greyhounds whose vets recommended biopsy and suffered fractures as a result of the biopsy. In my mind, unless you are prepared to either immediately euthanize or amputate, a biopsy is usually too risky. I was told by the oncologists at OSU that they recommend an ultrasound guided fine needle aspirate if there is a question whether the leg needs to be amputated. If both the x-rays, aspirate, and other clinical findings are inconclusive, then they make a decision whether a biopsy is warranted. It seems to me like they can look at an x-ray and at least 90 percent of the time feel confident in the diagnosis. But you would know the statistics better than me.

    I don’t remember the oncologists at OSU doing and aspirate of the lymph nodes. It is entirely possible that it was done and in my haze I don’t remember it. I do know that my Joe was part of numerous studies at OSU. One of them was regarding whether CAT scans were useful. So he had a CAT scan before his amputation. I don’t know if they just did the lungs or the whole body. I don’t know if they have results from this study yet.

    I am looking forward to your next article.


    • Dr. Susan Ettinger on February 24, 2013 at 9:04 am

      Thanks Jane! Glad to hear the info is helpful.
      Often the lymph node is just evaluated when the leg is submitted for biopsy.
      Thanks for sharing and reading.
      All my best, Dr Sue

  10. Kate obrien on February 11, 2013 at 3:14 pm

    Thanks for the continuing series on this. I wrote here last week and heard from several others going through the same issue and struggling with the difficult decision required when your pet has these types of critical health decision. My blog post: discussed our ordeal with Becca our rescue who developed osteosarcoma in her shoulder. Thanks for the added perspective and details about what to do.

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