Objective: This study evaluated the outcome with a treatment strategy for high-risk prostate cancer (PCa) using extended pelvic lymph-node dissection (eLND) followed by external beam radiation therapy (EBRT) in lymph-node-positive (LNpos) and lymph-node-negative (LNneg) cases compared with the strategy with limited pelvic lymph-node dissection (lLND) and only giving EBRT to LNneg cases., Materials and Methods: From 2000 to 2006, 124 men with high-risk PCa underwent lLND and initiated androgen deprivation therapy (ADT) before planned EBRT. LNpos patients were excluded from EBRT following the SPCG-7 study strategy (group I). From 2007 to 2013, 111 patients underwent eLND and started ADT before EBRT, and LNneg and most LNpos patients received EBRT (group II). Using Kaplan-Meier plots and multivariable Cox regression, biochemical recurrence-free, metastasis-free, cancer-specific survival and overall survival were compared during a 10 year follow-up., Results: PSA progression-free survival rates after 2, 4, 6, 8 and 10 years were 78%, 66%, 52%, 45% and 41% in group I, and 88%, 83%, 78%, 69% and 69% in group II (p < 0.001), respectively. Group II had a lower risk of PSA progression [hazard ratio (HR) = 0.43, 95% confidence interval (CI) 0.27,0.69, p = 0.001], metastasis development (HR = 0.51, 95% CI 0.27,0.97, p = 0.040) and overall mortality (HR = 0.49, 95% CI 0.26,0.92, p = 0.027), but not of PCa-specific death (HR = 0.45, 95% CI 0.19,1.08, p = 0.074)., Conclusion: A treatment strategy for high-risk PCa with eLND combined with EBRT in LNneg and LNpos cases may improve outcome compared to a strategy with lLND and offering EBRT only to LNneg cases but ADT to LNpos cases.