How to Calculate PSA Doubling Time

A series of Mayo Clinic studies links the rise in a specific antigen with the recurrence of prostate cancer. The clinic characterizes elevated Prostate Specific Antigen (PSA) levels as "biochemical failure." After biochemical failure, PSA levels in some men who have undergone prostatectomies continue to rise. Cancer more often recurs in these cases, and the increase in PSA often indicates residual cancer that never left the patient. Doctors measure the rate of PSA levels in terms of how often they double, known as PSA Doubling Time (PSADT).

Instructions

• 1

  Navigate your browser to the Sloan-Kettering PSADT calculator. (See Resources.)

• 2

  Enter the date of your first PSA reading in the "Date" box.

• 3

  Enter the reading, measured in nanograms per milliliter, in the "PSA" box.

• 4

  Click "Add."

• 5

  Repeat Steps 2 through 4 for each successive reading.

• 6

  Click "Calculate."