Here is a quote from UptoDate that answers the question:
"The preoperative concentration of serum PSA provides important predictive information for the likelihood of finding organ-confined disease (i.e. disease confined within the prostate -ed). As PSA levels increase, the likelihood of extracapsular (i.e disease outside the prostate -ed) disease rises. In one series, men with a preoperative serum PSA concentration of <10 ng/mL had a 70 to 80 percent likelihood of organ confined disease, compared to 50 percent for men with serum PSA >10 ng/mL, and 25 percent with serum PSA >50 ng/mL."
This would suggest that yes, the degree of PSA elevation is correlated to the spread of the cancer. That being said, most treatment decisions on prostate cancer is based on the stage of the cancer, rather than solely on the PSA level.
Followup with your personal physician is essential.
This answer is not intended as and does not substitute for medical advice - the information presented is for patient education only. Please see your personal physician for further evaluation of your individual case.
Kevin, M.D.
Medical Weblog:
kevinmd_b
Bibliography:
Klein. Early stage prostate cancer: Predicting the pathologic extent of disease. UptoDate, 2004.