Just to add - surgery isn't always an option, and even when it is, it's a personal decision, depending on the age of the hamster. Our last syrian had surgery for a small scent gland tumour removal at 21 months. It all went well but it was a stressful process. He had to cope in a little hospital cage for a week, loads of changes and upheaval. He had umpteen vet visits - the initial one, then the op, then a post op check up. All extra stress.
And all along he had secondaries and ended up with a horrible eye swelling and had to be put to sleep in the end.
Some people, with older hamsters with tumours, just let them live out their lives comforably until it comes to a time when they need help to relieve suffering - rather than put them through stress of surgery (if they are 2 or over). At 21 months I thought our hamster was ok for surgery. But in some ways I wish I hadn't and just let him enjoy his last few months.
When it's cancer they nearly always need to be pts - not always, but usually. It's relieving their suffering - cancer pain is horrible.
My vets don't do the injection in the heart either - they do it in the liver - which is why gas is needed first as the injection can take longer to work. That is just their protocol - anaesthetic and injection to the liver. If there was no anaesthetic and into the heart I think it would be awful - even if quick. Fear and pain.
As for burial or cremation - that's an individual thing. Our first hamster came home with us and was buried in the garden, but I have to say I found that incredibly hard. Bringing him home no longer alive. The second time I opted for individual cremation and that worked better for me. I could pick up the ashes a week or so later, after coming to terms with it. However I was shocked how expensive it was! It cost me about £90. I've done cremation with all of them since except one who died in his sleep. With him I wondered if I should have had him pts - he was dying for a couple of days. But then he went.
I still have the containers with the ashes. I was going to scatter them but kept putting it off, so they're all lined up on a shelf
Some people bury them in the garden and plant a shrub or plant there. I did this the first time. Some people bury them in a large pot and plant a plant in the pot. It's a natural way. If you do that, put some large stones in the bottom of the pot first.
I am so sorry about your little brother and I'm sure he's watching over you.
Whatever people say about euthanasia - it is the only option for a hamster who is suffering. There are very few licensed medicines for hamsters. Metacam is a pain relief medicine but not enough in later cancer stages. Hamsters are very good at hiding pain and can still be suffering.
You will know when it's the right time. I was very anti the idea initially, on principle. But I've changed my views now I know more. Ideally we would have hospice care for hamsters, as with humans, keeping them pain free to the end, but it isn't possible as there aren't the medications for that in such a tiny pet.
I think anaesthesia and sleeping is the next best thing.