Prognostic impact of reduced tumor-free margin distance on long-term survival in FIGO stage IB/II vulvar squamous cell carcinoma

OBJECTIVE: We aimed to identify the minimum tumor-free margin distance conferring long-term oncological safety in patients diagnosed with International Federation of Gynecology and Obstetrics (FIGO) stage IB/II vulvar squamous cell carcinoma (VSCC). METHODS: This was a retrospective cohort study in patients with stage IB/II VSCC treated at a single institution in Turin, Italy. The main aim was to identify the minimum tumor-free margin distance that confers oncological safety in early-stage VSCC. Patients were divided in groups according to tumor-free histological margin distance to compare survival outcomes. Overall survival (OS), disease-specific survival (DSS), and recurrence rate (RR) were estimated by the Kaplan-Meier method for the newly proposed and the currently recommended 8 mm margin cut-off. Log-rank test was used to compare survival between groups. RESULTS: One hundred and fourteen patients met the study criteria. Median age was 68 years and median follow-up was 80 months. The minimum margin distance that conferred long-term oncological safety was 5 mm. OS, DSS were significantly lower in the <5 mm group when compared with the ≥5 mm group (p=0.002 and p=0.033, respectively) although no difference in RR was observed between groups. Analysis at the 8-mm cut-off indicated there is no difference in OS, DSS, or RR between groups. CONCLUSION: FIGO stage IB/II VSCC patients' prognosis is affected by margin distance. Long-term survival is significantly reduced in patients with tumor-free margins <5 mm, even in the absence of lymph node metastasis. Thus, these patients should be offered further surgical or adjuvant treatment.