Does a groin node dissection in vulvar cancer affect groin recurrence and overall survival?: Results from a population-based cohort study

BACKGROUND: To determine, in a population-based cohort of vulvar cancer patients, if groin node dissection (GND) decreases the risk of groin recurrence and increases overall survival. METHODS: This population-based retrospective cohort study includes all cases of invasive squamous cell carcinoma identified in a provincial cancer registry from 1998 to 2007. Data collection was completed for all clinical and pathologic factors by chart abstraction. Cumulative incidence functions for recurrence were estimated, accounting for death before recurrence as a competing risk. Multivariable Cox regression models examined the associations between GND and groin recurrence, and overall survival. RESULTS: Clinical and pathologic data were collected for 1109 patients, of which 1038 patients were eligible for GND. 647 patients (62%) had a GND, while 391 patients (38%) did not. Median follow-up was 2.8years. Cumulative incidence plots demonstrate that the risk of death without recurrence was consistently higher than groin recurrence in each year after diagnosis. On multivariate analysis, GND was not significantly associated with decreased groin recurrence (HR 0.91, 95% CI 0.58-1.44, p=0.70). The hazard of death was 15% lower for women who received GND (HR 0.85, 95% CI 0.63-1.16, p=0.32), but this difference was not statistically significant. CONCLUSIONS: There was no significant difference in groin recurrence or overall survival in those with or without GND in this population-based cohort, raising questions whether a subgroup of patients may not benefit from GND. Patients had a higher probability of dying before groin recurrence could occur. Future trial design should consider death as a competing risk.