My russian dwarf hamster has a tumor is surgery an option?

My hamster Jeff has a tumor under neath his nose we have been to the vets who said to come back in 2 weeks unless it grows any bigger, he also said there's no point operating due to his size and age (27months) having searched this i have found that you can have operations would it be worth it? Is he in pain? He is still eating but not as much as he used to he is looking bonier than I'd like and has never used his wheel anyway.