The Role of PSA Testing in Advanced Prostate Cancer

The Group Room at the 2012 European Society for Medical Oncology (ESMO) Congress in Vienna was made possible, in part, by:

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Selma Schimmel, Founder & CEO, Vital Options International

This is Selma Schimmel for The Group Room at the ESMO 2012 Congress happening now in Vienna.

Is PSA and a rising PSA the best marker for late-stage diagnosis?

David I Quinn, MD:  Medical Director, USC Norris Cancer Hospital, Los Angeles

I think it’s one of the markers.  I think that patients become wed to it.  They’ve look at it for many years.  And I think PSA is one indicator but rather for the PSA to go down than go up, that’s usually the case.   But increasingly what we are seeing is a large group of patients that have relatively stable PSA and what I mean by that is a rise of not more than, say, 5 or 10% per time.  And we have with the newer drugs, for example, abiraterone and other generation drugs in that group such as TAK-700, a situation where your PSA can be slowly rising for a long time, more than a year, and you don’t have progressive disease on a scan.  So one PSA reading does not a summer swallow make.  The trend can be important.  If you are more than doubling on therapy, it’s probably not a good thing but you need to confirm that with some other evaluations such as scanning.  And also we use some things as game breakers now, so circulating tumor cells are often game breakers and we’ll do them periodically.  We don’t do them very often because we don’t know the right interval for people who are relatively stable but done a month apart they can actually determine a difference for the patient.  So, if the circulating tumor cells are going up and you think that there are some other parameters that suggest the patient is progressing…  I worry less about PSA and I worry a lot about pain.  If I have a patient who is in pain, they’re the ones that make me restless and I sort of roll over at night until it settles down or we get it under control.  And I think we’re doing better in that area.  Patients tend to lose sleep over their PSA and to the point where I’ve got patients that are woken up by their wives at 4 a.m. on the day they have to get their blood test.  It’s true; they’ve been doing this for years.  It’s a chronic disease, prostate cancer, for most people, so it’s natural.  We do need to get better markers and I just encourage patients who are looking at this to be aware of that and to try and look for trials and if they are offered trials of giving a little bit of extra blood or whatever it is to try to help with that.                                 

Maria De Santis, MD:  Kaiser Franz Josef Hospital, Vienna

Well, PSA is very popular as you have pointed out and it is very popular for screening for primary diagnosis and in this field it is very helpful, of course.  In patients being castration-resistant, those patients who progress on androgen-deprivation therapy and especially in those patients after chemotherapy at a later disease stage, PSA has shown to be not that helpful as in the beginning of the disease because disease changes and disease is dependent on the androgen receptor, on the one hand. On the other hand, there is disease that does not respond that well to certain treatments.  And PSA, for example, does not show a response or PSA progression does not show that the patient is really progressing with symptoms.  So, for the evaluation of our drugs, PSA has become a sort of problem in this late stage.  And in addition, those new drugs like abiraterone or enzalutamide have shown also PSA flares sort of false PSA rises that do not reflect a progression of disease.  And this makes the treatment in this state of disease more complicated because patients know a lot about PSA and they are worried when PSA is rising.  But we see that the patient is well and there are no major changes on the bone scan.  So I think it is important for the patients to know that PSA is not the most important sign of disease progression at this stage and with the use of these novel agents, for example.