When a man develops prostate cancer, his prostate cells undergo unrestrained growth; they multiply in an uncontrolled manner. Because those prostate cells manufacture PSA, their steady growth leads to a tell-tale rise in the man’s PSA level (as shown by a blood test).
The goal of a prostate cancer treatment should be the removal or killing of all the prostate cancer cells. If even one cell goes undetected, and remains in the man’s body, that one cell can divide again and again. The cancer has not been destroyed, and the man continues to harbor unwanted and growing, prostate cancer cells.
Cancer prognosis for a man who has undergone a cancer treatment relies on the ability to detect any remaining cancer cells. Only the total and complete removal of the prostate cancer cells can guarantee a good cancer prognosis. If even one cell escapes detection, it can launch another period of unrestrained cell growth. A patient who has been treated for cancer then continues to nourish dangerous prostate cancer cells.
Fortunately the PSA test gives the physician a way to uncover hidden cancer cells, cancer cells that have escaped a cancer treatment. The physician measures the patient’s PSA level immediately after the treatment. Then the physician gets a second measurement, one taken a week or more later. If a lone cancer cell is making PSA, then that should cause a noticeable rise in the man’s PSA level.
Because a prostate cancer prognosis depends so heavily on the PSA of the treated patient, that post-treatment measurement has been given a special name. It is called the PSA nadir. A low PSA nadir translates as a good prognosis for the man who has received a prostate cancer treatment.
Prior to the selection of a prostate cancer treatment, the doctor’s prognosis often relies on something called the Gleason score. The Gleason score is provided to a patient’s physician by a pathologist, the doctor who has examined tissue from a prostate biopsy.
The pathologist can discover what fraction of the cells has progressed beyond the early stages of cancer. If tissue taken during the biopsy of a prostate tumor has a large number of cells that show signs of rapid growth, then the doctor must consider that fact in making a prognosis. The patient would have a high Gleason score, and that high-scoring patient should consider, without delay, his desired course for treatment.
Often an older man has a low Gleason score. That older male patient would not need to consider immediate treatment. However, doctors would not cease all care for that low-scoring, older patient. That older patient could expect careful observation of the tumor’s growth. That careful observation would be called “watchful waiting.”