Hi Vincent and Kevin, welcome. Your future posts won't need to wait for approval so post away. 

I'm so sorry you are in this situation! It's a tough one and it's even harder when your dog is bigger than most. We will try to help you decide, and know that whatever path you take we are here to support you. 

So about this:

 The oncologist mentioned that if we don’t pursue chemo, there’s little point in doing additional testing or amputating the leg—though amputation could alleviate pain and prevent future fractures.

Are you positive that's what she said about amputation? Because amputating is the fastest way to alleviate the pain he is in. A limp = pain, bad pain when it comes to a bone cancer. I'm concerned about this comment because I've never met an oncologist who didn't stress the importance of at the very least amputating to alleviate pain, or doing stereotactic radiation therapy for palliative care if that is a possibility. Some people go the radiation route if their dog isn't an amputation candidate and that is perfectly OK.

 If we consider amputation, does that mean we also have to commit to chemo regardless?

Not at all! Chemo can statistically give a dog a better chance at living longer but it still cannot guarantee longevity. Lots of dogs do the chemo and still do not live up to the prognosis. Lots of dogs don't do chemo and go way beyond it. It is a total crapshoot.

MANY people do not do chemotherapy for whatever reason, myself included. It is crazy expensive and many dogs just don't do well with multiple vet visits. And that is OK! We opted out of chemo for osteosarcoma, and our Jerry lived 2 years after amputation! Some dogs go longer too. Chemotherapy is 100 percent optional, please don't let anyone tell you otherwise. The point is to get rid of the painful leg. Any bonus time after that is icing on the cake.

 Kevin has the chest of a lion (not an exaggeration), weighs 105 lbs (a mix of fat and muscle), and is still jumping in and out of my large SUV, on and off our beds, and going on 1-2 mile walks every day. He just started showing a slight limp last week, but it’s not too bad yet—he’s still jumping, running in circles, and being his usual self.

Please do not let him jump, or go on long walks right now. There is a huge risk of fracture if this is indeed bone cancer. You don't want to let the pain get so obvious he's limping even more, and you don't want a sudden fracture. It's horrific and puts you on the spot to decide immediately. 

Is he realistically going to be able to manage his weight and size with a front leg removed?

104 pounds is big but not the biggest dog we've seen here, some up to 175! If he is overweight, that will impact his mobility but you can help him lose the weight with your vet's help. The best orthopedic vets tell us that size alone should not be a determining factor. Bigger dogs may take longer to recover by a couple of weeks or so but they do recover!

Is he mentally going to adjust to waking up without a leg?

Yes! Animals do not carry the baggage that we do about amputation. Once his recovery is over he will move on with life and be the dog he always was. You will be amazed.

Is it right for me to take his leg at this point in his life? Is that an unfair decision to make for him at 9 years old, forcing him to adjust to losing a leg?

Many bigger dogs have gone through this at an older age. See our Size and Age Matters Forum, and Giant Breed News posts. If he is otherwise healthy and doing well, there's no reason why he can't live out the rest of his life happy and without pain. Many giant breed dogs who are much bigger get that extra time with their people.

Here's what I want to add: although you don't have a concrete diagnosis, the important thing to ask is: is the leg beyond saving? If so, there's no point in more diagnostics like a bone biopsy, because you are just creating more pain and more risk of fracture. These tests can happen once the leg comes off, if that's what you decide. And those tests are only really necessary if you are sure you want to pursue chemo. 

A final option you may want to consider is cementoplasty. It's relatively new here in the States but not overseas, and it's been done in human medicine for many years.  The cost is similar to amputation surgery and the dog gets to keep the leg. It's not a sure thing but neither is amputation as far as guaranteeing longevity. Not too many vets here in the US are doing it but more are getting on board. It's a nice alternative to radiation therapy and amputation if your dog is a candidate.

I hope this helps! Please keep us posted.

OK thank you for clarifying. A few thoughts:

I'm not a vet, so FWIW. But I take exception to "Chemotherapy is recommended afterwards as that is the only thing that will prolong his life after amputation."  The fact is, nothing will guarantee prolonging of life after amputation. Not chemo, not cementotplasty, nothing. Many people spenda  LOT of money for chemo, only to find that their dog did not live up to the prognosis of treatment. Chemotherapy is still a big crapshoot based on what we have seen here. Despite more and more dogs getting chemotherapy, survival rates have not improved for osteosarcoma. Don't get me wrong, I'm not against chemo at all. I Just feel like more people are given the impression that it's mandatory, and it is most definitely not. 

Treatments using chemo and immunotherapy can boost the odds, and recent studies are showing that it's the most promising treatment in three decades. But even then, it does not guarantee longevity or quality of life. Did the oncologist mention anything about immunotherapy as an option? 

Yes, "micrometastasis" is usually happening behind the scenes by the time a bone cancer diagnosis is given. But how fast those mets will impact quality of life is anyone's guess. Many dogs will go on for a long time with a great quality of life after amputation alone, despite micro mets coursing through their body. And, micromets can still be present even with chemo, there is no guarantee chemo will knock them out. That is the goal, but it's not a guarantee.

Yes, radiation therapy can weaken the bone, which is why bisphosphonates (bone building infusion therapy) are given. Most people like Hazel's dads, however, find themselves back at the amputation decision within a year because the tumor either comes back or the bone is weakened to the point of needing amputation asap.

As for finding out if the bone is beyond saving, just ask the vet. A destroyed bone will have a moth eaten appearance, or a tumor that is so big there is nothing that will decrease it. An x-ray alone will show if the bone is so far destroyed there is no saving it with radiation or cementoplasty. An orthopedic vet surgeon can give you the best answer but even a general practice vet can look at an xray and tell. Your path forward changes because it rules out limb-saving therapies like cementoplasty or radiation therapy, and it's either amputation or euthanasia.

Reach out to Biocera Vet and ask for a list of US vets who are doing the cementoplasty therapy. Let them know where you are in the U.S. 

Amputation can bring back quality of life once recovery is over. No, dogs are not exactly the same physically afterward, but they are happy and able to enjoy life again, in a slightly modified way. If chemotherapy visits will stress your dog, at what cost is that potential longevity? That's what you need to ask yourself. 

All stories are different, and all studies do not take your dog into consideration. Your decision is personal, as unique as your dog. Some people do chemo because they want to leave no stone unturned and their dog doesn't mind the vet. Some people don't do chemo for financial or temperament reasons. There is no judgement here. We will support you no matter what you decide.

Ok don't confuse immunotherapy with the marketing angles of boosting the immune system. Immunotherapy in the more evidence-based world is cancer vaccine therapies like the Yale Vaccine. This is a well studied treatment that is shown to boost the odds of longevity, and has legit science behind it. Check out the link.

Also, please be careful with any supplements that promise remission without amputation. Bone cancer is a seriously painful disease that needs addressing asap and no amount of CBD oil, food, or mushroom therapy will help with that pain. Don't get me wrong, I'm all for upgrading a dog's diet, but this type of pain is really bad so please don't put off veterinary treatment OK?

If it will make you feel better to get another opinion from a different oncologist, you might want to do that just for peace of mind.