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.