No bones about it...Osteosarcoma is a bad bone cancer :(

Meet Keres, this gorgeous 6 year old girl will steal your heart!   Here is her story, valiantly Battling Bone Cancer.

There is no way to sugar coat it… this cancer is very aggressive and, pun intended, Bad to the Bone.  As a veterinarian, I hate seeing this cancer, it has classical, recognizable manifestations, and it breaks my heart to give such bad news.  

Here are the characteristics: 

• Osteosarcoma tends to affect larger breed dogs
• It is very aggressive and painful
• It is a more common type of cancer affecting bones in the dog: accounting for ~85% of bone cancers
• It affects all ages; I’ve personally seen 2 year old dogs with it and 12 year old dogs.  When it is seen in younger dogs, it tends to be even more aggressive!

When Keres began limping on her right rear leg, her family thought she must have tweaked it.  After a few days, the limping persisted, so her family gave her an anti-inflammatory, and she improved.   However, after stopping the anti-inflammatory, the limp was back & to make matters worse, her leg was quite swollen. 

Its at this point that the family called to us to examine Keres.  This beautiful girl was perky & bright, but clearly not comfortable in her leg- she wasn’t able to place any weight on it and was even guarding it from the other pets in the home. Her knee was not only very swollen, but warm to the touch.  This was a dog-gone ouchy leg!

Normal knee 

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Very swollen knee (a different patient that Keres with bone cancer)

It can also affect the front legs, here are some pictures of the carpus (wrist area) with osteosarcoma:

Normal front leg carpus (wrist area) on a dog

Front leg carpus affected by osteosarcoma on a dog

Xrays were the next step in investigating what was going on with her knee. 

Normal dog knee and femur

Keres knee: The femur (bone in the upper half) has a fuzzy appearance around the bone with varying shades in the bone itself

Here are things to take notice of in the xrays:

• Often times, xrays are all that is needed to diagnose bone cancer
• The bone/s affected with cancer have a typical “moth eaten” or “sun burst” appearance
• The cortical bone- the white outer part is the strongest part of the bone (looks like a straight line in the normal bone).  In the cancer affected bone, we can see how the cortical bone has been affected, and it really affects the integrity of the bone, making it much easier to break (pathologic fracture)
• The osteosarcoma doesn’t not cross the joint space
• Usually the osteosarcoma is seen “away from the bones in the elbow area, but towards bones in the knee area.  It can also affect other bones, like those in the jaw, ribs, etc.

Once Keres’ had xrays, it was apparent that cancer was confirmed.  Osteosarcoma is presumed to be the type of cancer affecting her bones, at it is the most common bone tumor in dogs.  The way to be sure would be a bone biopsy (but this would further decrease the strength strength of the bone as we are taking out a chunk of it).  Or if amputation is chosen, the bone could be biopsied after that.

As important as what to do next, is how to control the intense pain caused by osteosarcoma.  Here are some common pain control options: 

• Keres, like most dogs with this type of cancer are extremely painful, despite pain relievers. 
• The best way to combat the pain is with several pain relievers, that work differently in the body, so as to create more comprehensive pain control.  Currenlty Keres is on tramadol, melixocam (an anti-inflammatory), and gabapentin.
• Another good options is to remove the source of cancer and affected bone: Amputation.  It may sound barbaric, but many dogs with bone cancer seem much more comfortable after removing that painful bone, and adjust quite well as a tripod.

Keres family elected amputation, but before considering amputation, it is a good idea to stage the cancer, or see if there is evidence of cancer elsewhere in the body.  Kere’s had xrays of her chest cavity and lungs, as well as rest of her body and bloodwork (to screen for organ dysfunction, evidence of cancer, etc).  Keres’ bloodwork was normal;  However elevations in ALKP have been found to have shorter survival times.  Thankfully Keres did NOT have evidence of cancer elsewhere in the body and her ALKP was normal!  Woo Hoo!  BUT, due to the aggressive nature of this cancer, it is common to have microscopic metastasis that may not be seen on X-rays.  She did well in surgery and immediately seemed more comfy with having that cancer-affected leg removed!

Keres day 1 post-amputation.  The family noticed her immediately more comfortable!

You may be wondering, what is the prognosis & options for treatment for dogs like Keres?   I always recommend a consult after a cancer diagnosis with a veterinary oncologist- they have the most up to date info on potential new therapies.  Here are some stats and options:

• The average survival for dogs who do not receive chemotherapy is 4-5 months from the initial diagnosis reagardless of amputation (but as noted earlier, it usually makes pets so much more comfortable living without that painful leg)
• Younger dogs affected with this type of cancer tend to have shorter survival times and more aggressive cancer.  Keres is 6 years old, so right in the middle.
• Chemotherapy is really the only way to significantly lengthen the life expectancy.  The chemo tends to be at intervals, and ~ 8 days in total; the protocols for pets don’t usually create as dramatic of side effects as what we see in people and hair loss is not seen. 
• There are potentially “limb sparing” options, which are more complicated-- where the affected (tumorous) bone in the leg is removed and replaced with a a bone graft or osteogenesis; these options work best for front leg tumors.
• Radiation can be helpful for pain control and noticeably helps with 2/3 of cases. 

Some veterinary schools have funding available to study trials.  Keres family is considering enrolling her in a clinical research study (http://uwveterinarycare.wisc.edu/clinical-studies/oncology/) 

Keres family is also trying some homeopathic options, including flaxseed and molasses.  None have been proven to help with osteosarcoma, but Keres family does think they are helping!  

Complications are so important to consider with this type of cancer as they can be tragic... I’ve seen both of these first hand…

• Pathologic bone fractures can occur.  I have seen pets break bones falling down stairs or tripping-- this makes them so much more painful!
• Excessive licking of the affected bones or even self mutilation (it really hurts!)

As I write this, Keres is still doing well.  We send lots of love and hugs out to Keres and any other dogs going through this!    If you have any more questions, please feel welcome to contact Dr. Christina.