Pear tree pruning

Hello, I have a pear tree that appears to be at least 8 years old. It is very tall and looks neglected. Coming out of the ground immediately next to the trunk are two shoots which i believe to be the root stock (they have thorns on, which may be a quince or pear stock). These shoots are very large 6 foot tall, at least 3 or 4 years old. My question is what to do with them? because they dont go back to the trunk, im not sure how to prune them off properly. The cultivated pear itself is nearly all vertical growth. Can this tree be saved? Its a new garden and I wonder if I should just replace it?

Cheers,