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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.)


Leave a Comment

  1. Rhonda Smith on February 25, 2021 at 5:14 am

    Dr Sue I have a five year old male mastiff that was diagnosed with Osteosarcoma in his front right leg in May 2020. We began exploring options of treatment and decided on the holistic approach. We transitioned him to a ruminant cooked diet, added daily supplements of 5 defenders (with pure mushrooms). life caps, and Neoplasene 1mg x2 daily. He was doing very well until Nov 2020 when the tumor began to grow. We then decided to amputate his leg. we took him to a vet that specializes in this and he was there for 3 days. After coming home the results were incredible. Two days after surgery he decided to go up our back steps to the porch and showed us that he could manage very well. We have tried to limit his activity but he often rebels and does what he wants. We have been shocked at how quickly he healed and often acts like he is like a puppy again. Very playful, runs, dances, and wont allow us to restrict him- although we continue to try. Since his surgery he has continued the Neoplasene 1mg daily x2 on his food (still ruminant cooked diet) and we are continually working with our Holistic vet. We decided against the chemotherapy and radiation at her advise (against the advise of the surgeon at the other clinic).I have read all of your articles and I would really appreciate your opinion on this choice we have made, and what you think his long term outcome will be. Its been 4 months since the amputation and his x-rays still show clear lungs and chest. Do you think the Osteosarcoma will eventually return? And would you suggest the continued use of the Neoplasene? If so, for how long?
    Thank you Rhonda Smith

  2. Devon Nalley on September 24, 2020 at 4:30 pm

    Hi Dr. Sue!
    Thank you so much for writing this blog post, it was incredibly informative. I have been researching osteosarcoma and read that my Great Dane is more at risk because he has a metal plate in one of his back legs from when he broke it as a puppy.
    It seems like by the time dogs are symptomatic and taken to the vet because they’re limping or a mass has formed, the cancer has already metastasized. Would annual or bi-annual x-rays be able to catch osteosarcoma before a dog is symptomatic? I want to do as much as I can to make sure we detect it early should he ever develop any form of cancer.
    I read your Facebook post from 6/16 about screening tests, but was wondering if there is anything else that can be done to detect the types of cancer most common in Great Danes and other giant breeds.

  3. James Earnhart on July 22, 2019 at 12:22 pm

    My Lab has Deff signs of OSA right above left front paw and the Biopsy came back Neg for OSA. Why is that when even xrays are showing that its getting worse ? So now my only option is to go ahead with amputation anyways and hope it saves her. And these are UF Grads and UF pathologists. Even they are puzzeled. So can u tell me whats going on ???

  4. Tripawds » Pre-Amputation Diagnostic Tests on July 12, 2016 at 9:01 pm

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

  5. Janna Jones on March 19, 2013 at 6:35 pm

    My dog(Gunner) is a German shorthair pointer. Almost 13 years old but acts like a puppy. He is very healthy and hikes with my son alot. 29 miles the last hike. With in 3 days he got a huge lump on his jaw. And started to scream when he yawned. I took him to his vet and they did a tissue biopsy which confirmed what he suspected and has bone cancer in his jaw boe. It is right in the joint. He is on metacam every 24 hrs. and has tramadol for the times it really hurts him. I just ordered a sedative from the vet to keep on hand in case he gets into trouble and the pain meds don’t work any more. He is eating really good and quality of life so far is good. I just wanted to share as this is a monster and apparently it is the most painful kind of cancer. You can’t amputate his jaw really….

    • Dr. Susan Ettinger on April 5, 2013 at 10:13 am

      Sorry about Gunnar. Surgery CAN be an option for the jaw, especially the lower jaw. A CT scan is very useful to determine if surgery is an option. Have you considered a consult with a surgeon or oncologist?
      If not, radiation (full-course or palliative) are options for the local tumor.
      All my best, Dr Sue

  6. Osteosarcoma and Amputation: myths and facts on February 28, 2013 at 10:41 pm

    […] my last blog, I gave my recommendations about osteosarcoma (OSA) work up. Now it’s time to talk about […]

  7. Shawne Johnson on February 20, 2013 at 4:39 am

    OMGoodness! A friend and co-worker just sent me your blog! SPOT ON! One of my Afghan Hounds who will be 2 years mid-April is currently going through all of this. I was struggling with the vet’s recommendation of a biopsy and wanted to just go with the amputation. Thank you for your comments because now I can submit it to the vet as support to just amputate.

    Still is awe of your analysis…. dogs with long hair… large breeds…. 1.5 to 2 years of age…. limping… then lame… then swelling! HOLY MACKEREL! You are AWESOME!

    Surgery is next week! Fingers cross and all prayers appreciated!

    • Dr. Susan Ettinger on February 24, 2013 at 10:01 am

      So glad you found me here! Keep us updated. You can also update me on my FB page, Love pics and videos!
      All my best, Dr Sue

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