Predictive Value of an Alternative Strategy for Measuring Depth and Size of Stage 1 Vulvar Squamous Cell Carcinoma

Despite poor reproducibility for measuring vulvar cancer depth, 1-mm or greater invasion triggers lymphadenectomy for small tumors. Previous literature suggests that measuring depth from the nearest dysplastic rete peg (alternative method) rather than highest dermal papilla (conventional method) may be acceptable.

Pathologic staging and follow-up information were recorded for 100 pT1 vulvar squamous cell carcinoma (SCC) resected from 1990 to 2019. Conventional depth, alternative depth, gross/clinical size, and size of the invasive component were measured for each tumor. In this retrospective study, we evaluated which clinicopathologic factors were most predictive of lymph node involvement and recurrence.

Depending on the measurements used (conventional vs alternative depth, clinical lesion size vs cumulative extent of invasive component), between 1 and 18 cases were downstaged to pT1a. All such cases were pN0, without lymphovascular or perineural invasion. Infiltrative cords (hazard ratio [HR] = 5.15; 95% CI = 1.63-16.2; p = .005) and perineural invasion (HR = 3.16; 1.18-8.45; p = .022) were most strongly associated with groin recurrence. Of staging criteria evaluated, only cumulative extent of the invasive component 2 cm or greater was significantly associated with groin recurrence (HR = 2.87; 1.01-8.17; p = .048). The Kaplan-Meier curves for local recurrence-free survival by stage did not show significant separation regardless of method.

Patients downstaged using alternative measurement techniques lacked nodal disease/recurrence; one-third of those with nodal sampling experienced postoperative morbidity. Our data suggest that the use of alternative depth and cumulative extent of invasion could safely allow some conventional stage IB vulvar SCC patients to avoid groin surgery, thereby reducing treatment-related morbidity.