[The role of pelvic lymphadenectomy in the therapy of prostate and bladder cancer]

Abstract

The rationale for locoregional staging lymphadenectomy in prostate cancer lies in the accurate diagnosis of occult micrometastases in order to stratify patients who might benefit from adjuvant therapeutic measures. In prostate cancer, extended pelvic lymphadenectomy (EPLA) including the lymphatic tissue along the common iliac region with the ureteral crossing as cranial margin, external and internal iliac region and the obturator fossa, has been shown to increase the yield of both total lymph nodes and lymph node metastases significantly. The total number of lymph nodes removed is about 2- to 3-fold higher and the frequency of micrometastatic lymph nodes is approximately 2-fold higher compared to standard lymphadenectomy. Furthermore, the frequency of observed positive lymph nodes in clinically localized and locally advanced prostate cancer is significantly higher than predicted by nomograms such as Partin tables and CART analysis. Although there are no prospective randomized trials demonstrating a survival benefit associated with EPLA, there might be an advantage for those with minimal lymph node involvement. Progression-free survival is significantly improved in patients undergoing EPLA with a 35 % benefit compared to standard lymphadenectomy. Various studies have documented an equal risk of cancer-associated mortality in patients with no or only 1 - 2 positive lymph nodes. Since the surgery-associated morbidity of EPLA is not increased as compared to standard lymphadenectomy, EPLA should be favoured at least for all intermediate and high risk patients undergoing radical prostatectomy; in low risk patients the option of EPLA has to be discussed thoroughly. For the future, ongoing prospective trials have to demonstrate a clear benefit in terms of biochemical-free and cancer-specific survival. With regard to muscle-invasive bladder cancer, it has been shown that lymph node dissection along the external, internal and common iliac artery and obturator fossa achieves accurate data for a valid locoregional staging. Only if frozen section analysis reveals metastatic deposits along these areas an extension of the lymphadenectomy including the aortic bifurcation up to the inferior mesenteric artery seems to be of additional diagnostic value. Various studies have demonstrated that extended pelvic lymphadenectomy results in an improvement of progression-free survival, however no significant benefit with regard to cancer-specific and overall survival has been demonstrated. Nevertheless, pelvic lymphadenectomy remains one of the most significant prognosticators with regard to relapse rates as has been demonstrated recently and, therefore, it should be performed thoroughly and anatomically adequate.