PDF forms to word and back to PDF

I work with files which had been sent to the US EPA and those are in pdf format.  I need to make changes to a lot of the pdf files, by converting them to Word and then - after the changes which could be an additional sentence or two or a removal of one - convert it back to pdf in the same format as it came in.   In other words the format should look the same.  Lines and boxes.  Is this feasible?   I've heard of another system called Nuance which may be an alternative, but I would prefer to utilize Adobe systems.   HELP???