--in the recent research, the doctor is well within the clinical guidelines by currently engaging in "watchful waiting" until the PSA goes above 4.

Considering that almost anything that irritates the prostate in men can cause the PSA to rise--and that Alan has certainly had issues with autoimmune inflammation--if the numbers continue to rise at the rate they are now, it would probably be worth it for him to have an ultrasound of the area.

Analyses like this one are pretty typical of what I've found:

http://www.urologystein.com/psa.shtml

There are some dissenting viewpoints like this one (but even most of these find levels below 10 to be only "moderately elevated"):

http://www.cancer.gov/cancertopics/f.../Detection/PSA

As Liza Jane notes, the rate of increase--termed the "velocity"--is important, though apparently more predictive in those with already diagnosed prostate cancer.

Another possibility (you can mention) here is have Alan's free PSA measured along with the total PSA--elevated free PSA compared to total PSA (the ratio is often reported) is more likely indicative of a benign conditions such as prostatitis or benign enlargement.