Prediction of functional outcomes after nerve-sparing radical prostatectomy: results of conditional survival analyses

Background

In prostate cancer (PCa) patients treated with radical prostatectomy (RP), the rate of urinary continence (UC) and erectile function (EF) recovery may change significantly depending on the time interval between surgery and patient assessment. This effect, known as conditional survival, has not yet been assessed.

Objective

Evaluate the conditional rates of UC and EF recovery after nerve-sparing RP (NSRP).

Design, setting, and participants

We included 1135 PCa patients treated between January 2000 and June 2011 at a single referral center.

Intervention

All patients underwent NSRP.

Outcome measurements and statistical analysis

The Kaplan-Meier method assessed the time to recovery of UC (defined as an International Consultation on Incontinence Questionnaire score <6) and of EF (defined as an International Index of Erectile Function-Erectile Function score ≥22). Cumulative survival estimates were used to generate conditional recovery rates assessed at a 6-mo interval. Multivariable Cox regression analyses were performed to predict functional outcomes recovery after accounting for confounders.

Results and limitations

UC recovery rates were 89.5%, 94.7%, and 97.0% at 6-, 24-, and 36-mo follow-up, respectively. Corresponding EF recovery rates were 53.6%, 65.0%, and 67.5%, respectively. In patients who were still incontinent at 1, 6, 12, 18, 24, 30, and 36 mo after surgery, UC recovery rates in the following 6-mo period significantly decreased as the time from surgery increased: 74.9%, 58.2%, 41.4%, 14.9%, 24.8%, 24.6%, and 13.3%, respectively. Similarly, in patients still impotent at the same time points, the 6-mo rate of sexual potency recovery was 36.9%, 26.8%, 17.8%, 8.2%, 3.1%, 4.0%, and 0%, respectively. Multivariable analyses confirmed these results. The study is limited by its retrospective design.

Conclusions

In incontinent and/or impotent patients, the period elapsed from surgery represents an important predictor of the recovery of subsequent functional outcomes. The highest increments in UC and EF recovery were observed during the first year after surgery; they were virtually null after 36 mo.