Preoperative predictors of inguinal lymph node metastases in vulvar cancer – A nationwide study

Background: A combination of tumour size, differentiation grade and location may identify a group of vulvar squamous cell cancer (VSCC) patients with a very low risk of inguinal lymph node metastasis. We aim to examine these findings in a large national cohort of VSCC patients. Materials and methods: Population based prospective data on VSCC patients treated with vulvectomy and primary groin surgery was obtained from the Danish Gynaecological Cancer Database. Univariate chi-square and multivariate logistic regression analysis were used. Statistical tests were 2-sided. P-values of <0.05 were considered statistically significant. Results: In all, 388 VSCC patients were identified. Of these 264 (63.3%) were node negative and 121 (36.7%) node positive. Increasing tumour size (diameter ≤ 2 cm vs. > 2 to 4 cm), grade (1 vs. 2–3) and location of tumour to clitoris were all associated with a significantly increased risk of inguinal lymph node metastasis OR 2.81(95% CI 1.52–5.20), OR 3.19 (95% CI 1.77–5.74) and OR 2.74 (95% CI 1.56–5.20), respectively. Previous vulvar disease was not associated with lymph node metastasis. No lymph node metastasis was demonstrated in patients with grade 1 tumours, tumour size less than 2 cm and located outside the clitoris area (n = 51). Conclusions: VSCC patients with grade 1 tumours, ≤ 2 cm and without clitoral involvement have a very low risk of inguinal lymph node metastasis. These patients may be spared inguinal lymph node staging to decrease operating time and peri- and postoperative morbidity in the future. However, studies validating our findings are needed.