A) Preoperative nomogram estimating the 1- to 10-year progression-free probability after radical prostatectomy alone. B) Calibration plot of the nomogram in external validation. The 45° line represents an ideal model in which estimates of recurrence are perfectly calibrated with outcome. Vertical bars are 95% confidence intervals for quintiles in the validation set.
Instructions for physician: Locate patient's preoperative prostate-specific antigen (PSA) on the Preoperative PSA axis. Draw a straight line down to the Points axis to determine how many points toward disease recurrence that patient receives. Repeat this process for each of the remaining variable axes. Sum the points for each predictor and locate this sum on the Total Points axis. Draw a line straight up from the Total Points axis until it intersects with the horizontal line drawn from Months from Surgery, corresponding to the time point in the future within which the risk of recurrence is wished to be calculated. The progression-free probability can be estimated at 12 to 120 months after radical prostatectomy. The slanted vertical line that crosses this intersection point corresponds to the calculated progression-free probability within that point in time after radical prostatectomy.
Instructions for patient: Mr. X, if we had 100 men exactly like you, we would predict <predicted probability from nomogram×100> percent to remain free of disease progression at <specified months from surgery> following radical prostatectomy alone.