6th July 19:55
I've done some more checking on the web to refresh the little I know
about ultrasensitive PSA testing following a radical prostatectomy. It
appears that there is some controversy about this. Some people feel
the ultrasensitive tests provide a warning many years in advance of real
recurrence. They claim that any value above 0.01 ng/ml is detectable
and suggest the PSA will continue to rise. Needless to say, the
companies that sell the equipment to do such testing and the labs that
do it believe that is the case. On the other hand, other urologists,
particularly those at Hopkins, think that values that low don't mean
anything. They think there can be considerable variation at the level
of .02 - .05 on a day to day basis, which doesn't mean anything. They
stick by the criterion that if it is below .1 it is undetectable and
they say there is no point in using tests which distinguish values below
that. Presumably both camps can cite studies supporting their case.
Perhaps Roy's radiologist is in the first camp. But he still should
have told Roy that there is some difference of opinion about the matter,
and he believes that PSA is only truly undetectable if the measured
value is below 0.01. I don't think it makes sense to talk about a
measured value of zero because there is always a certain experimental
error involved. But the radiologist may mean a value below 0.01 when
he says it should be zero.
I don't know what the current consensus among urologists is about which
side is right.