A retrospective analysis shared during the 2021 Society of Urologic Oncology Annual Meeting determined the optimal number of lymph nodes that should be excised to maximize overall survival (OS) in men with intermediate- and high-risk prostate cancer undergoing radical prostatectomy.1
Explaining the rationale for the study, first author Furkan Dursun, MD, a urologic oncology fellow at The University of Texas Health San Antonio, said, “The role of limited versus extended pelvic lymph node dissection (PLND) in the surgical management of prostate cancer remains controversial. We sought to conduct a National Cancer Database (NCDB) analysis evaluating the impact of the extent of lymphadenectomy on survival outcomes for patients presenting with intermediate- and high-risk prostate cancer.”
The study included 103,250 patients from the NCDB with newly diagnosed intermediate- or high-risk prostate cancer who received radical prostatectomy and PLND between 2004 and 2013. Intermediate risk was defined as stage cT2b-2c disease and/or a PSA level of 10-20 ng/mL and/or a Gleason grade group of 2 or 3. High risk was defined as stage ≥cT3 disease and/or a PSA level of >20 ng/mL and/or a Gleason grade group of 4 or 5.
Patients were aged <70 years with a Charlson Comorbidity index score of 0. About three-fourths (74.2%) of the patients had intermediate-risk disease and about one-fourth (25.8%) had high-risk disease.
The number of excised lymph nodes was used as a surrogate for the extent of PLND. Accordingly, patients were separated into 3 groups based on the number of excised nodes. Group 1 had 1-9 excised lymph nodes, group 2 had 10-19, and group 3 had ≥20. Overall, 80.5% of patients were in group 1, 15.9% were in group 2, and 3.6% were in group 3.
The primary end point was OS. “All-cause mortality was evaluated using propensity score weighted Kaplan Meir Curves and Cox regression models,” explained Dursun. The secondary end point was the rate of lymph node–positive disease among different groups.
Statistical modeling showed that among intermediate-risk patients, there was an OS benefit for group 2 versus group 1 (HR, 0.86; 95% CI, 0.79-0.93; P <.001). There was not an OS benefit for group 3 versus group 1 (HR, 0.9; 95% CI, 0.76-1.05; P = .186).
In the high-risk prostate cancer cohort, there was no OS benefit for group 2 versus group 1 (HR, 0.98; 95% CI, 0.85-1.13; P = .815); however, there was an OS benefit for group 3 versus group 1 (HR, 0.61; 95% CI, 0.47-0.78; P <.001).
Dursun added that, “Pathologically proven lymph node–disease positive rates were significantly higher in group 3 compared to group 1 and group 2 in both intermediate- and high-risk prostate cancer patients.”
Specifically, the lymph node–positive disease rate in the intermediate-risk cohort was 9.25% in group 3 versus 1.53% and 4.45% in groups 1 and 2, respectively (P <.001). Among high-risk patients, the lymph node–positive disease rate was 25.25% in group 3 versus 5.65% and 15.53% in groups 1 and 2, respectively (P <.001).
“Our results showed that for men with high-risk prostate cancer, removal of 20 or more nodes during radical prostatectomy was associated with better survival outcomes. A similar survival benefit was noted in the intermediate-risk group with removal of 10-19 lymph nodes,” Dursun said in his concluding remarks, adding that, “Increased number of removed nodes was associated with increased likelihood of lymph node positivity and more accurate pathologic staging.”
1. Dursun F, Elshabrawy A, Wang H, et al. Impact of extent of lymphadenectomy on all cause mortality in patients with intermediate- and high-risk prostate cancer managed with radical prostatectomy. 2021 Society of Urologic Oncology Annual Meeting. December 1-3, 2021; Orlando, FL. Abstract 143.