Lymphatic spread of nodal metastases in high-risk prostate cancer: The ascending pathway from the pelvis to the retroperitoneum.

BACKGROUND: The aim of this study was to map the nodal metastases distribution in patients with high-risk prostate cancer (PCa) treated with extended pelvic lymph node dissection (ePLND) and retroperitoneal lymph node dissection (rLND) at the time of radical prostatectomy (RP).
MATERIALS AND METHODS: This prospective mapping study included 19 patients with high-risk PCa (sharing at least two out of the three following parameters: PSA >20 ng/ml, cT3, biopsy Gleason score ≥8). All patients were treated with RP, ePLND (removal of the obturator, hypogastric, external iliac, presacral, and common iliac lymph nodes) and rLND (removal of para-aortal/para-caval and inter-aorto-caval lymph nodes) by a single surgeon. All patients signed an informed consent highlighting the absence of clinical data supporting the benefit of this surgical approach.
RESULTS: Overall, 18 out of 19 patients (94.7%) had pelvic lymph node invasion. The most commonly affected pelvic nodal landing site was obturator (88.8%), followed by external iliac (83.3%), common iliac (77%), hypogastric (44.4%), and presacral (33.3%). Moreover, 14 (77.8%) patients also had involvement of retroperitoneal lymph nodes. Only patients with positive common iliac lymph nodes having at least five positive lower pelvic lymph nodes (n = 14), also had invariably positive retroperitoneal lymph nodes. No patients with negative common iliac lymph nodes had positive retroperitoneal lymph nodes.
CONCLUSIONS: PCa lymphatic spread ascends from the pelvis up to the retroperitoneum invariably through common iliac lymph nodes. PCa lymphatic spread can be divided in two main levels: pelvic and common iliac plus retroperitoneal lymph nodes.