Incidence of inguinofemoral lymph node metastases at the first local recurrence of vulvar cancer: a Dutch nationwide study

Background: Up to 40% of vulvar cancer patients present with local recurrence within 10 years of follow-up. An inguinofemoral lymphadenectomy (IFL) is indicated if not performed at primary treatment. The incidence and risk factors for lymph node metastases (LNM) at first local recurrence, however, are unclear. Our aim was to determine the incidence of LNM at first local recurrence, in relation to previous groin treatment and clinicopathological factors. Methods: A multicenter cohort study including vulvar cancer patients with a first macroinvasive local recurrence after primary surgical treatment between 2000 and 2015 was conducted in the Netherlands. Groin status at local recurrence was defined as positive (N+), negative (N−) or unknown (N?) and based on histology, imaging and follow-up. Patient-, tumour- and treatment characteristics of primary and recurrent disease were analysed. Results: Overall, 16.3% (66/404) had a N+ groin status at first local recurrence, 66.4% (268/404) N− and 17.3% (70/404) N? groin status. The incidence of a N+ groin status was comparable after previous SLN and IFL, 11.5% and 13.8%, respectively. A N+ groin status was related to tumour size (25 vs.12 mm; P < 0.001), depth of invasion (5 vs. 3 mm; P < 0.001) and poorly differentiated tumours (22.9 vs. 11.9%; P = 0.050) at local recurrence. Conclusions: The incidence of LNM at first local recurrence in vulvar cancer patients was 16.3%, and independent of previous type of groin surgery. In accordance with primary diagnosis, tumour size, depth of invasion, and tumour grade were significantly associated with a positive groin status.