That is not true, a cancer or a tumor on rodents can be surgically removed.
The question would be whether putting the mouse through surgery (the risk, the pain, the anesthesia) would benefit the mouse and improve its life considerably compared to if it were to live with the tumor.
As I've mentioned before, tumors and cancers are prevalent in small rodents because of inbreeding and hence they are in their genes. If the mouse can still carry out its daily activities with no struggle (perhaps because the tumor is benign), I don't think it's a good idea putting the mouse through the pain & suffering of surgery, especially with the risk of the mouse not waking up after anesthesia. If it's very painful and surgery is only a temporary fix (as tumors & cancers do return), then euthanasia might be an option.
I've had hamsters with cancers, some had to be put down because the cancer was so progressive, but some I've decided to let them live out their lives the vet told me that the cancer doesn't seem to bother the hamster. It really depends on the situation.
The question would be whether putting the mouse through surgery (the risk, the pain, the anesthesia) would benefit the mouse and improve its life considerably compared to if it were to live with the tumor.
As I've mentioned before, tumors and cancers are prevalent in small rodents because of inbreeding and hence they are in their genes. If the mouse can still carry out its daily activities with no struggle (perhaps because the tumor is benign), I don't think it's a good idea putting the mouse through the pain & suffering of surgery, especially with the risk of the mouse not waking up after anesthesia. If it's very painful and surgery is only a temporary fix (as tumors & cancers do return), then euthanasia might be an option.
I've had hamsters with cancers, some had to be put down because the cancer was so progressive, but some I've decided to let them live out their lives the vet told me that the cancer doesn't seem to bother the hamster. It really depends on the situation.