DE does not need pruning. My garden is fenced from deer, so I cannot speak to that question.

The first thing that deer eat are any rose buds on a bush. They will go through a rose garden and eat every single bud. EVERY SINGLE ONE! It's like they are harvesting green peas and baby Brussels sprouts. You will be left with bushy foliaged roses, minus flowers. If deer can reach it they will eat it.

Moses

Actually, the deer do leave it alone. It may be because the thing is such an enormously awkward size and shape that it isn't easy for deer to reach the buds.

That is the good news. The bad news is that like any other rose, the individual canes only live so long, then they have to be cut out. This is a horrendously awful job that tends to involve a fair amount of blood loss, and destruction of everything nearby. The canes you are trying to get out can, and do get caught on everything.

Here, I have not blessedly had to cut anything out in 8 years or so. Different zone maybe.

My Darlows gets "pruned" by the deer constantly - thorns are not a deterrent, as deer eat soft new shoots which do not have hardened thorns on it. You can see the browse line on the bush: there are never any blooms lower than 4.5 feet above the ground.