Hi,I have just found a hard lump on my oldest dog's(he's 16)chin,and I think it could possibly be cancer,and when I felt round his neck and shoulders he felt really tense .I will take him to my vet asap,can they tell just by a blood or urine test as he has a heart murmur and I don't want too much done that will be too stressful?He also has a lump under his tail which was tested for cancer 2 years ago,and was negative then,but he has lost a bit of weight lately,and I'm scared of having to make hard decisions,if it is cancer,I will do what is best for him,as he's had a cracking life,and don't want him to suffer.

Maybe your vet could do just a fine needle aspiration on the lump?  That way your dog wont need sedation and it will only take a few seconds to get a biopsy.  Hope you get on ok with him x

Hard lumps can be something or nothing, there's no telling until the vet sends a sample off to the lab I'm afraid, a blood test wouldn't tell them anything conclusive.