Predicting an optimal outcome after radical prostatectomy: the trifecta nomogram

Abstract

Purpose: The optimal outcome after radical prostatectomy for clinically localized prostate cancer is freedom from biochemical recurrence along with the recovery of continence and erectile function, a so-called trifecta. We evaluated our series of open radical prostatectomy cases to determine the likelihood of this outcome and develop a nomogram predicting the trifecta.

Materials and methods: We reviewed the records of patients undergoing open radical prostatectomy for clinical stage T1c-T3a prostate cancer at our center during 2000 to 2006. Men were excluded if they received preoperative hormonal therapy, chemotherapy or radiation therapy, if pretreatment prostate specific antigen was more than 50 ng/ml, or if they were impotent or incontinent before radical prostatectomy. A total of 1,577 men were included in the study. Freedom from biochemical recurrence was defined as post-radical prostatectomy prostate specific antigen less than 0.2 ng/ml. Continence was defined as not having to wear any protective pads. Potency was defined as erection adequate for intercourse upon most attempts with or without phosphodiesterase-5 inhibitor.

Results: Mean patient age was 58 years and mean pretreatment prostate specific antigen was 6.4 ng/ml. A trifecta outcome (cancer-free status with recovery of continence and potency) was achieved in 62% of patients. In a nomogram developed to predict the likelihood of the trifecta baseline prostate specific antigen was the major predictive factor. Area under the ROC curve for the nomogram was 0.773 and calibration appeared excellent.

Conclusions: A trifecta (optimal) outcome can be achieved in most men undergoing radical prostatectomy. The nomogram permits patients to estimate preoperatively their likelihood of an optimal outcome after radical prostatectomy.

Figure 1

The probability of biochemical recurrence (BCR) over time in 1577 men undergoing radical prostatectomy. The number at risk is shown above the x axis.

Figure 2

The probability of recovery of continence (pad free) and potency (rigidity scale 1 or 2) after radical prostatectomy (RP)

Figure 3

Trifecta probability for an individual patient after radical prostatectomy (RP). This is the probability of reaching and maintaining trifecta for a patient with average characteristics in our series: pre-RP PSA of 5.4, clinical stage T1c, normal pretreatment erectile function (rigidity scale 1), prostate biopsy Gleason grade 3+3, and pre-RP age of 58.2 years

Figure 4

Nomogram predicting the likelihood of attaining a trifecta outcome after RP. The definitions of continence (the patient does not wear pads) and potency (rigidity scale 1 or 2) are the same prior to and after RP. Note that even a minor loss of erectile function (pre-RP rigidity scale 2 versus 1) is a risk factor for not achieving a trifecta outcome. Note: This is to be used only prior to surgery, not during follow-up.

Figure 5

Calibration plot for the trifecta nomogram. Histogram at the bottom illustrates the distribution of predicted probabilities.