Pelvic Lymph Node Dissection in Prostate Cancer: Update from a Randomized Clinical Trial of Limited Versus Extended Dissection.

BACKGROUND AND OBJECTIVE

Lymph node dissection (LND) has been standard in cancer surgery for more than a century, yet evidence from randomized trials showing a benefit is scarce. We conducted a clinically integrated randomized trial comparing limited versus extended pelvic LND (PLND) during radical prostatectomy and previously reported comparable biochemical recurrence (BCR) rates. We report updated BCR rates and compare rates of metastasis between the study arms.

METHODS

Between October 2011 and March 2017, 1432 patients undergoing radical prostatectomy were enrolled at a single center. Surgeons were cluster randomized to perform limited (external iliac nodes) or extended PLND (external iliac, obturator, and hypogastric nodes) with crossover for 3-mo periods. Cox proportional-hazards regression with robust standard errors clustered by surgeon was used to assess whether the PLND template affected BCR or distant or locoregional metastasis.

KEY FINDINGS AND LIMITATIONS

There were 452 BCR events at median follow-up of 4.2 yr for participants who did not develop BCR. The results confirm our previous finding of comparable BCR rates between the arms (hazard ratio [HR] 1.05, 95% confidence interval [CI] 0.97-1.13; p = 0.3). However, with 123 metastasis events and median follow-up of 5.4 yr for patients without metastasis, we found a clinically and statistically significant protective effect of extended PLND against metastasis (any metastasis: HR 0.82, 95% CI 0.71-0.93; p = 0.003; distant metastasis: HR 0.75, 95% CI 0.64-0.88; p < 0.001).

CONCLUSIONS AND CLINICAL IMPLICATIONS

Patients undergoing radical prostatectomy should receive extended PLND that includes the external iliac, obturator, and hypogastric nodes. Further research should examine biological mechanisms regarding the anatomic location of affected nodes. Trials of LND for other cancers are warranted and should consider our clinically integrated design. This trial is registered on ClinicalTrials.gov as NCT01407263.