Autopsy studies show that many men have microscopic evidence of prostate
cancer which never rises to a level that is clinically signficant.   If
the cancer is large enough to be detectable clinically with current
techniques, it may or may not ever be a problem for the patient.  It is
still an open question as to how often clinically diagnosed cancers are
innocuous, and physicians and researchers continue to debate the matter.
 There are some studies, for example, which suggest that at least 15
percent, and possibly significantly more, cases which today are treated
aggressively would never bother the patient during his life.   The
likelihood of that decreases as the aggressiveness of the cancer
increases, but there is no specific test which allows a physician to
decide that with a very high probability a specific case need not be
treated.  There are some general guidelines that physicians folow.
Thus, Gleason 2-4 cases would generally not be treated aggressively.
Also, many Gleason 5 and some Gleason 6 cases might also not be treated.
 A lot can depend on the life expectancy of the patient because the
overwhelmingly majority of prostate cancers grow very slowly.  On the
other hand few urologists would treat a Gleason 7 or higher cancer as
innocuous.  Such cancers are usually treated aggressively in men who
otherwise might be expected to have a resonable life expectancy.  Older
men with more aggressive cancers might still not be treated by surgery
or radiation because the benefits of such treatment during the patient's
lifetime might be less than the risks.   All patients who have
metastatic disease or show evidence that it is imminent will be treated
by hormone therapy.  Exactly when to begin it is a matter that
physicians differ about.

In your specific case, if you have a typical Gleason 6=3+3, T1c case
with PSa less than 10, and you are in your late 60s or older, then you
may be a candidate for expectant management, which defers treatment
until there is evidence of accelerated growth of the cancer.  Whether or
not you are a candidate will depend on tumor volume and other factors.
But if, like me, you have a Gleason 7 tumor, and you have a life
expectancy beyond 5-10 years, your doctor will probably recommend
surgery or radation.

Matters of this kind are discussed both in Walsh's book and in
Scardino's book, from which most of my information comes.  But I've also
been following some of the medical literature on the subject which seems
to confirm what these two experts say.