Do I Need Treatment?
The lifetime risk of developing prostate cancer for a man in the
United States is 13%. However, up to 50% of men are found to have
microscopic cancers in their prostate at autopsy. These observations
have led some to criticize PSA testing because it may identify
cancers that are incidental and would never trouble the patient
during his lifetime. This has been a popular theme in the lay press
recently. What are the facts?
If you can feel a cancer (stage B or T2-T3), it is almost always a
significant tumor that requires treatment. If your cancer cannot
be felt but is detected only by a serum PSA, it is possible that you
could harbor a small cancer. In a study of 150 men with cancers that
could not be felt (stage Tlc) who underwent radical prostatectomy at
Johns Hopkins Hospital, 11 % of men with PSA levels greater than 4
had very small cancers (ɘ.2 cc and confined to the prostate).
We subsequently identified some criteria to help identify those
patients prospectively so that they can be cautioned about the need
for aggressive therapy. If the cancer was present in 3 cores
of tissue, or involved more than half of 1 core, or was Gleason
7 or greater, the amount of tumor found at radical prostatectomy was
always significant. These patients should be strongly encouraged
to undergo therapy. However, if the patient has none of these
findings and if his PSA density (serum PSA divided by the prostate
weight estimated from transrectal ultrasound) is in the range of
0.1 to 0.15 then there is a good chance that the patient harbors
a small cancer. Based upon the age and desire of the patient, it
may be wise for these patients to be followed expectantly. If
they elect to do so, they should undergo a digital rectal
examination and serum PSA every six months and needle biopsies
once a year. We cannot rely upon serum PSA alone because it is
known that approximately 25% of patients with cancers that progress
in size do not have a concomitant increase in their serum PSA.
- Epstein, J.I., Walsh, P.C., Carmichael, M., & Brendler, C.B.:
Pathologic and clinical findings to predict tumor extent of
nonpalpable (stage T1c) prostate cancer. JAMA 271:368-374, 1994.