Measuring the depth of invasion in vulvar squamous cell carcinoma: interobserver agreement and pitfalls

Abstract

AimsThe depth of invasion is an important prognostic factor for patients with vulvar squamous cell carcinoma (SCC). The threshold of 1 mm distinguishes between FIGO stages IA and ≥IB disease and guides the need for groin surgery. Therefore, high interobserver agreement is crucial. The conventional and the alternative method are described to measure the depth of invasion. The aims of this study were to assess interobserver agreement for classifying the depth of invasion using both methods and to identify pitfalls.Methods and resultsFifty slides of vulvar SCC with a depth of invasion approximately 1 mm were selected, digitally scanned and independently assessed by 10 pathologists working in a referral or oncology centre and four pathologists in training. The depth of invasion was measured using both the conventional and alternative method in each slide and categorised into ≤1 and >1 mm. The percentage of agreement and Light’s kappa for multi‐rater agreement were calculated, and 95% confidence intervals were calculated by bootstrapping (1000 runs). The agreement using the conventional method was moderate (κ = 0.57, 95% confidence interval = 0.45–0.68). The percentage of agreement among the participating pathologists using the conventional method was 85.0% versus 89.4% using the alternative method. Six pitfalls were identified: disagreement concerning which invasive nest is deepest, recognition of invasive growth and where it starts, curved surface, carcinoma situated on the edge of the tissue block, ulceration and different measurement methods.ConclusionsPathologists reached only moderate agreement in determining the depth of invasion in vulvar SCC, without a notable difference between the two measurement methods.

Assessment of recurrence rate and risk factors of relapse in stage in IA vulvar carcinoma

“…Fifty VSCC cases with a depth of invasion of approximately 1 mm were selected and examined by 10 specialists. After reviewing the slides, the number of cases stated as microinvasive ranged from 16 to 36 while the number of cases with a depth of invasion >1 mm ranged from 11 to 33 [27]. This may call for a further clarification of the FIGO measurement system and a more standardized reporting of depth of invasions and margins.…”

Evaluating the impact of a digitally implemented subjective standard on professional rugby union player management decision-making

“…Agreement was interpreted as slight (0.01–0.20), fair (0.21–0.40), moderate (0.41–0.60), substantial (0.61–0.80) and almost perfect (0.81–0.99). 23,24 The 95% confidence intervals (CIs) of the agreement measures were calculated via bootstrapping with replacement (1000 runs). Bootstrapped samples were paired across the four time points with the point estimate Kappa ( κ false^*) of each sample calculated in each bootstrap step.…”

European Society of Gynaecological Oncology Guidelines for the Management of Patients with Vulvar Cancer - Update 2023

“…Some prognostic relevant staging tumor factors were re-allocated between stage subgroups to achieve similar survival rates (non-osseous organ extension included originally in stage IVA in 2009 was downstaged to IIIA stage by 9 In addition, a new measurement of depth of invasion in vulvar cancer was introduced in FIGO 2021, which is analogous to cervical cancer, as it might better reflect prognosis, although interobserver variability between pathologists remains moderate. [10][11][12] Based on the limited evidence, the working group The 2021 FIGO staging allows incorporating findings from crosssectional imaging into vulvar cancer staging. 7 The 8th editions of the TNM staging systems of the American Joint Committee on Cancer (AJCC) and the International Union Against Cancer (UICC) for the vulva were published in 2017 and apply for primary carcinomas.…”