Effect of known pathological risk factors on the incidence of metastatic lymph nodes and survival in early-stage vulvar cancer: SEER analysis

Objective: The current study was performed to evaluate the incidence of positive lymph nodes (LNs) in relation to known pathological risk factors, specifically among patients with apparent low-grade, small tumors.Methods: We used the Surveillance, Epidemiology, and End Results (SEER) database to retrospectively identify patients with vulvar squamous cell carcinoma (SCC) diagnosed between January 1, 2000, and December 31, 2019, with known tumor size and regional LN examined. A comparison between patients who had positive and negative LNs was conducted to identify risk factors for LN metastases in relation to survival. Subgroup analysis was conducted in patients with diagnosed grade 1 vulvar SCC and tumor size up to 2 cm according to the status of LNs.Results: Multivariate analysis found that both grade of disease and tumor size were significant factors in predicting LN status. Among patients with low-grade small tumors up to 2 cm, the odds ratio for positive LNs was 2.5 for those with tumor size larger than 1 cm. In a multivariate survival analysis, older age, larger tumor size, and positive LNs were independently associated with decreased survival.Conclusions: The current study confirms that among small tumors, those larger than 1 cm have a significantly increased risk for positive nodes compared with those smaller than 1 cm, and, among this specific group, patients with positive nodes have decreased survival. Future studies are needed to answer the question of whether, in the era of the sentinel node procedure, it is safe to omit LN evaluation altogether.