Surgeon heterogeneity significantly affects functional and oncologic outcomes after radical prostatectomy in the Swedish LAPPRO trial.

OBJECTIVES: To evaluate how surgeon heterogeneity - the variation in outcomes between individual surgeons - influenced functional and oncologic outcomes after robot assisted radical prostatectomy (RALP) and retropubic radical prostatectomy (RRP), and to assess whether surgeon heterogeneity affected the comparison between RALP and RRP.

PATIENTS AND METHODS: Laparoscopic Prostatectomy Robot Open (LAPPRO) is a prospective, controlled, non-randomized trial performed at 14 Swedish centers with 68 operating surgeons. 4,003 men with localized prostate cancer were enrolled between 2008-2011. The endpoints were urinary incontinence, erectile dysfunction and recurrence at 24-months after surgery. Logistic regression models were built to evaluate surgeon heterogeneity and, secondarily, surgeon-specific factors were added to the models to investigate their influence on heterogeneity and the comparison between RALP and RRP.

RESULTS: Among surgeons who performed at least 20 surgeries during the study period, we observed statistically significant heterogeneity for incontinence (p=0.001), erectile dysfunction (p<0.001) and the rate of recurrent disease (p<0.001). The significant heterogeneity remained when analyzing only experienced surgeons with a stated experience of at least 250 radical prostatectomies. Among all participating surgeons, differences in surgeon volume explained 42% of the observed heterogeneity for incontinence (p=0.003), 11% for erectile dysfunction (p=0.03) and 19% for recurrence (p=0.01). Taking surgeon volume into account when comparing RALP and RRP had a significant impact on the results. The effect was greatest for functional outcomes and the additional adjustments for the surgeons´ prior experience changed whether the difference between techniques was statistically significant or not. The surgeons´ annual volume had the greatest effect on the recurrence rate.

CONCLUSIONS: Heterogeneity among surgeons regarding both functional and oncologic outcomes were large and had a significant impact on the results when comparing RALP and RRP. Some of the observed heterogeneity was explained by differences in surgeon volume. Efforts to decrease heterogeneity are warranted and variation between surgeons must be accounted for when doing comparative analysis between surgical techniques.