Sentinel Node Extended in Squamous Cell Vulvar Cancer

Time to extend the indication for sentinel node biopsy in vulvar cancer? Results from a prospective nationwide Swedish study

To assess detection rates and negative predictive values of sentinel node biopsy in vulvar squamous cell carcinoma with tumors ≥4 cm, multifocal tumors, and in locally recurrent disease. Between December 2019 and December 2022, patients with vulvar squamous cell carcinoma with tumors ≥4 cm (group 1), multifocal tumors (group 2), or a first local recurrence without or with previous groin treatment (groups 3 and 4, respectively) were included in a prospective, nationwide multicenter interventional pilot study. The participants underwent a sentinel node biopsy followed by inguinofemoral lymph node dissection. Detection rates, negative predictive values, the proportion of micrometastases, and isolated tumor cells were determined separately for each group. In all, 64 women were included, 36 women in group 1 (56%), and 17 women in group 2 (27%). Due to the small number and heterogeneity of the 11 women in groups 3 and 4, they were excluded from further analyses. In groups 1 and 2, 25 women (47%) were diagnosed with node-positive disease, and in 16 women (64%) only in the sentinel nodes. The detection rates varied between 94.1-100% per patient and 84.1-85.3% per groin. No false-negative sentinel nodes were identified, giving a negative predictive value of 100% for group 1 (95% CI 91.2% to 100%) and for group 2 (95% CI 83.9% to 100%). Of the node-positive patients, 32% had micrometastasis or isolated tumor cells only. One third of the metastases were detected by ultrastaging. In 27% of the non-mapping groins, metastases were found in the lymphadenectomy specimen, and in 75% the metastases showed extranodal growth. In this small cohort of patients, we provide further data that may widen the indication of the sentinel node technique to women with tumors ≥4 cm and multifocal tumors. NCT04147780.

Can we extend the indication for sentinel node biopsy in vulvar cancer? A nationwide feasibility study from Sweden

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. 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. Sentinel node biopsy has an acceptable negative predictive value and detection rate in the study cohort. 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 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. The primary endpoints are the detection rate and the negative predictive value of the sentinel node procedure. 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. The trial is registered at "ClinicalTrials.gov" (ID: NCT04147780).

Diana Zach