Does the Number of Lymph Nodes Resected During Radical Cystectomy for Squamous Cell Carcinoma Really Matter?
Kristian Stensland, MD, MPH1; Mark Broadwin, BA2; Lawrence Zhang, BA2; Joan Delto, MD3; Peter Chang, MD, MPH3; Andrew Wagner, MD3
1Lahey Hospital and Medical Center, Burlington, MA; 2Tufts University School of Medicine, Boston, MA; 3Beth Israel Deaconess Medical Center, Boston, MA
BACKGROUND: Radical cystectomy is the gold standard treatment for muscle invasive bladder cancer of both conventional and variant histologies. While greater extent of nodal dissection during cystectomy has been associated with increased survival for conventional urothelial carcinoma, the impact of nodal dissection for squamous cell carcinoma has not been described. If a greater lymph node yield does not improve survival, an extended lymph node dissection during cystectomy could be potentially be avoided.
METHODS: The National Cancer Database was queried for muscle invasive, non-metastatic, clinically node negative squamous cell carcinoma of the bladder undergoing radical cystectomy without perioperative chemoradiation. Only cases reporting number of lymph nodes retrieved and positive (including reporting 0 nodes retrieved) were included. Overall survival was estimated via the Kaplan-Meier method. Multivariate Cox proportional hazards methods were used to assess the effect of node dissection extent on overall survival. Multivariate logistic regression models were created to assess the effect of node dissection extent on 30- and 90-day mortality, 30-day readmission rates, and likelihood of positive lymph nodes.
RESULTS: A total of 505 cases were eligible for inclusion, of which 83 (16.4%) had 0 nodes removed, 186 (36.8%) had 1-10 nodes removed, 230 (45.5%) had 11-19 nodes removed, and 6 (1.2%) had >20 nodes removed. Five year survival for these groups was 35%, 35%, 50%, and 33%, respectively. Median overall survival via KM estimate was 37.4 months [95% CI 24.9-51.9 months]. Number of nodes removed at time of cystectomy did not significantly affect overall survival (HR 0.99, 95% CI 0.98-1.003, p = 0.16) when adjusted for clinical T stage, sex, and Charlson comorbidity index. When grouping node extent, removal of 11-19 nodes compared to 0 nodes may improve overall survival (HR 0.76, 95% CI 0.54-1.07, p = 0.11); removal of 1-10 or >20 nodes did not impact survival. Node dissection did not affect 30- and 90-day mortality or 30-day readmission rates. In exploratory analysis, more extended lymph node dissection was significantly associated with likelihood of at least one positive lymph node (HR 1.03, 95% CI 1.01-1.05, p = 0.008).
CONCLUSION: Excision of a greater number of nodes during radical cystectomy for squamous cell carcinoma yields a higher likelihood of finding positive nodes, but it is unclear if this affects overall survival. Node dissection extent does not affect 30-day readmission rates. At present, there does not appear to be sufficient evidence to forego a lymph node dissection during cystectomy for squamous cell carcinoma.
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