Yes, big prostates can contribute to slightly elevated PSA.   So what?   As
to your question you can reduce postate size by surgery, if you are having a
problem having a pee.   Or by meds which interfere with DHT--if that is your
cause--long term side effects of these meds are worth examining closely.
Likely you are like everyone else on the newsgroup with either BPH or
Prostatitis.   Porstatis can raise PSA, since infections of the prostate can
do that, but I don't think 7.2 is time for panic.  Has your doctor done a
prostate massage to excrete fluid to examine for infections that can be
treated with antibiotics?  Has he done a blood test to determine other
bacteria that may be infecting the prostate?  Or did he just give you a
quick answer to get you on your merry way?   Has he mentioned BPH?   Cancer
is much rarer than BPH. It'd check out all the other causes before I'd let
my doctor start biopsy for possible cancer.   But you should defer to
fgomsan@gmail.com  who appears to be a real doctor.