Effects Of Pathologic Stage On The Learning Curve For Radical Prostatectomy

Main Category: Prostate / Prostate Cancer
Also Included In: Urology / Nephrology;  Men's health
Article Date: 08 Mar 2008 - 0:00 PDT

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UroToday.com - In the online version of European Urology, a group from Memorial-Sloan Kettering Cancer Center, the Cleveland Clinic and Wayne State investigate how pathologic stage would affect the learning curve in radical prostatectomy (RP) for prostate cancer (CaP). Andrew Vickers is the lead author.

There is existing evidence that the outcomes of cancer surgery are associated with characteristics of the operating surgeon. Surgeons with higher annual case volume have lower mortality rates for numerous procedures. This study hypothesized that differences in the learning curve between organ-confined and locally advanced CaP would be informative as to cancer biology. The study cohort analyzed 7,765 men who underwent RP by 1 of 72 surgeons at 4 institutions between 1987 and 2003. Cancer recurrence was defined as a serum PSA >0.4ng/ml with a second, higher subsequent PSA. Locally advanced CaP was defined as the presence of extracapsular extension, seminal vesical invasion, or lymph node involvement. A multivariable, parametric survival-time regression model was performed. The researches adjusted for differences in case mix and included clinical and pathologic variables. For each patient surgeon experience was coded as the number of RPs performed by the surgeon prior to the patient's operation. The question was whether more experienced surgeons have better results irrespective of pathologic stage, or whether the association between experience and outcome depends on pathologic stage in the RP specimen.

There were 5,342 patients with organ confined CaP and 2,423 patients with locally advanced CaP. A moderate, but statistically significant negative association between pathologic stage and surgeon experience was found. This appeared due to stage migration, as no important association between surgeon experience and organ-confined status when analysis was restricted to patients treated after 1995. A total 1,256 recurrences were identified at a median follow-up time of 3.9 years. Surgeon experience was associated with outcome for both patients with organ-confined or locally advanced CaP. The learning curve for locally advanced CaP reached a plateau at a 30% probability of recurrence at 5 years, whereas for organ-confined CaP the learning curve continued to rise towards a 100% recurrence-free probability. Among patients with organ-confined CaP operated on by surgeons who performed at least 1,000 prior RPs, the median 5-year recurrence-free probability was 97%. The learning curve for advanced CaP was steeper, with the adjusted 5-year probability of recurrence for a surgeon with 250 prior cases was 22% after 1995 compared to 36% in the entire series, but similar to the main analysis this reached a plateau at approximately a 30% probability of recurrence at 5 years. Thus the learning curve for locally advanced disease flattens at approximately 70%, suggesting that about a third of these patients cannot be cured by surgery alone.

Eur Urol. 2008 Jan 14 [Epub ahead of print]

Vickers AJ, Fernando Biancob FJ, Gonena M, Cronina AM, Easthamb JA, Schraga D, Kleinc EA, Reutherc AM, Kattand MW, Pontese E, Scardinob PT

Reported by UroToday.com Contributing Editor Christopher P. Evans, MD

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