Is It Necessary To Remove The Seminal Vesicles Completely At Radical Prostatectomy?

In the February issue of the Journal of Urology, a group from Memorial Sloan Kettering Cancer Center tested the European Society of Urological Oncology (ESUO) recommendation that the seminal vesicles may not need to be removed at the time of radical prostatectomy (RP). The purpose of seminal vesicle sparing is to decrease the potential for post-operative impotence. They find that the issue is a complex statistical one and requires further analysis to increase certainty.

The ESUO recommendation is based on a retrospective analysis of 1,283 men of whom 137 (10.6%) had seminal vesicle invasion (SVI). The ESUO reported that PSA, biopsy Gleason score and number of biopsy cores positive were predictive for SVI and proposed that patients with PSA 10ng/ml or greater, Gleason score >6, or >50% cores positive were at risk for SVI and should undergo SV removal. The opposite criteria could be spared complete SV resection.

The ESUO also recommended that a prospective trial confirm their findings, but the MSKCC analysis determined that >10,000 patients would need to be included, making this infeasible. As such, the MSKCC group applied an independent data set to the ESUO algorithm to determine the predictive value.

The dataset consisted of 2,959 men treated with RP between 1998 and 2004. Of these, 1,406 were appropriate for analysis. All had complete removal of the SVs and pelvic lymphadenectomy. SVI was recorded when prostate cancer cells invaded the muscular layer of the SV wall. Patients were considered ESUO positive with a PSA 10ng/ml or greater, Gleason score >6, or >50% cores positive. Otherwise they were considered ESUO negative. They determined that the sensitivity and specificity applied would justify the clinical use of the ESUO prediction rule. A false negative result (failing to remove the SV when tumor is involved) had greater adverse consequences than a false positive result (unnecessary removal of a SV free of tumor). As a result, they used a decision curve analysis to evaluate the clinical value of the ESUO rule - they incorporated the clinical consequences of using a prediction rule by applying a different weight to positive and false-positive results.

They found that 30 patients had their biopsy Gleason scores of 6 upgraded on RP, and 4 of these which were classified as ESUP negative showed SVI. Ninety of 1,406 patients had SVI (6.4%). Of the men, 741 (53%) were classified as ESUO positive, most commonly due to a biopsy Gleason score of greater than 6. Of the 90 patients with SVI, 81 were ESUO positive for 90% sensitivity and 656 of 1,316 without SVI were ESUO negative for 50% specificity. The negative predictive value was 98.6%. None of the 9 men with SVI who were negative by ESUO criteria had pelvic lymph node metastasis.

By statistical calculations, the MSKCC group determined that if the loss in health when SVs are invaded and not completely removed is considered at least 75 times greater than unnecessary removal, then the ESUO algorithm should not be used. They suggest that a formal decision analysis should be performed to further answer this question prior to broad application of the algorithm.

Secin FP, Bianco FJ, Cronin A, Eastham JA, Scardino PT, Guillonneau B, Vickers AJ
J Urol. 2009 Feb;181(2):609-13
doi:10.1016/j.juro.2008.10.035