We all know that the PSA test is certainly harmful and not expensive. However, it is also not perfect. Until we have something better why, in cases of smallest doubts and in practice, biopsy is not used less parsimoniously ?
Is there presently any research to identify better tools than the PSA ?
Third question ?
According to what I read, chemotherapy does not work for hormono refractory advanced prostate cancer ?. What is the rate of success among patients treated by chemotherapy ?
Fourth question ?
Some doctors say that angiogenesis inhibitors may cause thrombosis, some doctors say that they do not ? Where is the truth ? What is the solution for patients taking this type of drug such as the thalidomide ?
I will address the question on chemo first. For years we have treated patients with hormone-refractory prostate cancer and observed good results in at least 50% of patients with decrease in serum PSA and decrease in pain and improvement in quality of life of these patients. The Canadians conducted a study with the combination of a chemo drug, Mitoxantrone + Prednisone and compared this to prednisone alone and found that patients who took the chemo did better with less pain and better quality of life. Based on that study which was published in 1996, the FDA approved the chemo drug Mitoxantrone for treatment of androgen independent prostate cancer (AIPC) or known as hormone-refractory prostate cancer (HRPC). So the combination of Mitoxantrone + prednisone became an accepted regimen for these patients with AIPC/HRPC although there were urologists or even oncologists who were skeptical. Later another chemo drug was found to be effective in AIPC/HRPC, Taxotere, which by itself produced about 40% response with PSA decrease in patients with AIPC. This year, at the American Society of Clinical Oncology meeting, which took place in New Orleans June 4-8, two papers were presented, one comparing Taxotere + Prednisone versus Mitoxantrone + Prednisone, the other comparing Taxotere + Estramustine versus Mitoxantrone + Prednisone. Both papers showed statistically significant survival benefit for the Taxotere-containing regimens, without excess side effects compared to Mitoxantrone + Prednisone. The response rate with Taxotere + prednisone and Taxotere + Estramustine was about 50%. So there is no question now that, in addition to decreasing pain and improving quality of life, chemo does also prolong life in patients with AIPC/HRPC.
About angiogenesis inhibitors, it is true in general there is concern these drugs may cause thrombosis or bleeding; which one of the two complications is seen depends on the agent, and some may cause less problems than others.
-Nizar Tannir, M.D.
Yes, there are currently studies being conducted to investigate other proteins related to prostate cancer which may be more specific, related more to prostate cancer and less to normal prostate tissue. The problem with PSA is that it is produced by both normal prostate and cancer. This new science is called "proteomics".
-Deborah Kuban, M.D.
1. Biopsies are not without complications including sepsis, bleeding, and death. Increasing the use of biopsy may detect more cancer but many men will undergo unnecessary biopsy to detect a relatively small amount of cancers. And one could question the biologic significance of these cancers that are found. If men life long enough, all will develop prostate cancer. With annual prostate screening (DRE and PSA), and attention to PSA velocity and changes in DRE, the liklihood of a clinically significant cancer remaining undetected is low.
2. Research is ongoing to examine the various forms of PSA in the blood (free, complexed and others) to increase the sensitivity and specificity of the test. Other markers are being looked at including human kallekrein 2 and others. Remember, even though PSA isn't perfect, it is better than any other test we have for other cancers.
3. Dr. Tannir elegantly addressed this question
4. Dr. Tannir addressed this as well. With regards to thalidomide, we are recommending aspirin or low dose coumadin to prevent thromboembolic complications.
-Dr. Christopher Wood