Tub and Shower surrounds are the hardest areas of construction to make water tight. While building or remodeling a shower or tub area is the perfect time to get the sub structure correct to prevent this area from leaking and prematurely needing repairs.
Using cement backer board as a stable base for your tile will help you make a leak proof shower surround as it will not deteriorate or warp if water does reach it.
Check out this great video on installing backer board in your surround.
Using this method will give great confidence that your surround will last a long time.