Background In squamous cell vulvar cancer, sentinel node biopsy is accepted as standard treatment in well-defined patient groups and has reduced surgical morbidity considerably. Currently, due to the lack of evidence, it cannot be offered to patients with tumors of 4 cm diameter or greater or with multifocal tumors, or in local recurrences.

Primary objective This study is primarily a pilot and feasibility trial, aiming to evaluate if the prerequisites concerning detection rate and negative predictive value are satisfactory before the implementation of a multinational trial.

Study hypothesis Sentinel node biopsy has an acceptable negative predictive value and detection rate in the study cohort.

Trial design This study is planned as a prospective, national, multicenter interventional trial. Participating patients will undergo a sentinel node biopsy in addition to an inguinofemoral lymphadenectomy.

Inclusion and exclusion criteria Inclusion criteria: for women in group 1, a primary tumor ≥4 cm in diameter; in group 2, a multifocal primary tumor; in group 3, a local recurrence without previous inguinofemoral lymphadenectomy or radiation to the groins; in group 4, a local recurrence, with previous inguinofemoral lymphadenectomy and/or radiation to the groins.

Primary endpoint The primary endpoints are the detection rate and the negative predictive value of the sentinel node procedure.

Sample size In each of the four study arms, recruitment of 20–30 patients is planned.

Estimated dates for completing recruitment and presenting results Recruitment will take place between November 2019 and October 2021. Results will be available in December 2021.

Trial registration The trial is registered at “ClinicalTrials.gov” (ID: NCT04147780).