Uptake of sentinel lymph node procedures in women with vulvar cancer over time in a population based study

To evaluate trends in uptake of sentinel lymph node (SLN) procedures over time and associated factors in women with vulvar cancer.

A retrospective population-based cohort study identified women with invasive squamous cell carcinoma (SCC) of the vulva using health administrative data for the province of Ontario, Canada, between 2008 and 2016. Patients who underwent SLN procedures were compared to those who had groin node dissection (GND). Multivariable analysis was used to identify factors associated with SLN procedures.

1385 patients with SCC of the vulva were identified; 1079 had a surgical procedure. Only those with groin node assessment were included in the study cohort (n = 732, 68%). SLN procedures were done in 52%. When comparing SLN versus GND, the rate of SLNs was significantly different by year of diagnosis (P < 0.001), associated comorbidity (P < 0.001) and institution (P < 0.0001). The rates of SLNs by institution with gynecologic oncologist were variable and ranged from 32% to 79% among 9 centers. There were no differences in age, income quintile, and urban/rural residence. The proportion of SLN procedures increased from 30.1% (CI 18.9-45.6) in 2008 to 65.2% (CI 36.5-107.6) in 2016. On multivariate analysis, factors significantly associated with SLN procedures were more recent year of diagnosis (OR 7.9, CI 2.7-23.5) associated comorbidities (OR 2.7, CI 1.5-5.0) and institution (Site 5, OR 19.6 [CI 3.6-108.3] and Site 6, [OR 6, CI 1.1-33.4]).

The proportion of SLN procedures in women with vulvar cancer has increased over time, but uptake is not uniform across institutions. Barriers to uptake should be explored.