I would use a closet flange with the pipe glued into each side. The
flange
will be in the center of the concrete and act as a water stop, making the
water have a longer path. Concrete only sticks to pvc when you don't
want
it to. Vibrations in the plumbing, temperature changes, and other
factors
will cause the pvc to become lose in the hole, but the closet flange is
thoroughly anchored.

Do I have to cut the pipe or are you recommending passing it through the
flange? I found some online...however it is a little hard to figure if the
pipe will pass through the flange.

The closet flanges seem to run about 5 bucks which is a LOT cheaper than
the $45 4 inch water stop I found.
http://www.recreonics.com/fyi/wall_fittings.htm

Thanks