Risk stratification of groin node metastases in vulvar cancer biopsies based on histology and immunohistochemical staining

OBJECTIVE: In vulvar squamous cell carcinoma (VSCC), the presence or absence of groin lymph node metastases (LNM) is relevant for choice of treatment and outcome. Risk stratification at time of primary diagnosis could impact choice of treatment, especially since VSCC often affects elderly patients with increased surgical risks. This study evaluates the prognostic value of histopathological features and immunohistochemical (IHC) markers (p16, p53, L1CAM, and PD-L1) for predicting groin LNM in primary biopsy specimens. METHODS: A retrospective cohort study was conducted, including patients with macroinvasive VSCC (depth of invasion >1mm) undergoing primary surgery between 2005 and 2015. Pathological revision of both the primary biopsy and definitive resection was performed. IHC staining with p16, p53, L1CAM, and PD-L1 was applied to all biopsies. The primary outcome was the risk of groin LNM at primary diagnosis. RESULTS: A total of 118 patients were included, of whom 34.7% (n=41) had groin LNM. In resected specimens, groin LNM correlated significantly with depth of invasion ≥4mm (p=0.002), poor differentiation (p=0.002), invasive or spray-patterned growth (p=0.024), and lymphovascular space invasion (LVSI) (p