Charlie,

I don't know anything about mistletoe, but I do remember from the
case of Martin Howard, who kept a journal of his cancer progression,
that his PSA did not go up in a straight line.  There were fits and
starts and at least one regression.

My understanding is that PSA can vary up to 30% in one day.  I
speculate that this is caused by varying amounts of PSA producing
activity by the tumor cells, not by a 30% increase or decrease of
the number of cells.  I can easily imagine that a man who read his
PSA on a particularly active day followed by a reading on a relatively
inactive day might well think his cancer was "arrested" or even
reversed.

So even if every other possible cause of error is ruled out (i.e.,
Wayne Diamond is not a lying mistletoe salesman.  His PSA
readings are accurate.  He is not self-deluded.  He has not
had a remission due to some non-mistletoe cause.  etc.), it
is still possible that his arrested PSA does not indicate
therapeutic benefit from mistletoe.

Now, having said all that, I did a search on mistletoe in Pubmed.
There are a number of articles indicating a beneficial effect against
cancer including at least one claiming that some breast cancer
patients were able to extend their lives using mistletoe extracts.

If you search Pubmed you'll see the abstracts.

   Alan