Concordance of Squamous Cell Carcinoma Histologic Grading Among Dermatopathologists and Mohs Surgeons

Abstract

BACKGROUND Current staging systems for cutaneous squamous cell carcinoma (cSCC) incorporate histologic grade. There are no universally agreed on criteria to define differentiation for cSCC. OBJECTIVE To determine the interrater and intrarater reliability among dermatopathologists and Mohs surgeons in grading histological differentiation for cSCC. METHODS AND MATERIALS One hundred thirty-one archived slides were selected. Three dermatopathologists and 3 Mohs surgeons graded the tumors in a blinded manner (Round 1). In an attempt to improve concordance, all 6 participants were then asked to regrade the tumors based on a devised quantitative grading scale (Round 2). RESULTS For Round 1, overall κ was 0.56 corresponding to a weak agreement. κ for well, moderate, and poorly differentiated tumors was 0.68, 0.39, and 0.59, respectively, corresponding to moderate, minimal, and weak concordance. For Round 2 of the study, overall κ was 0.60, with κ = 0.75, 0.46, and 0.61 for well, moderate, and poorly differentiated tumors, respectively. Overall intrarater reliability was 0.70 (κ = 0.70, 0.77, 0.68, 0.71, 0.56, and 0.75), corresponding to a moderate concordance. CONCLUSION Overall concordance for cSCC histologic grading is weak to moderate among the experimental group. Substantial differences in concordance exist among histological degrees of differentiation, with lowest agreement in moderately differentiated tumors.

Incorporation of the 40-Gene Expression Profile (40-GEP) Test to Improve Treatment Decisions in High-Risk Cutaneous Squamous Cell Carcinoma (cSCC) Patients: Case Series and Algorithm

“…48,49 Furthermore, evaluating subjective clinicopathologic factors like "degree of differentiation" or "rapidly growing tumor", having multiple measurements of depth of invasion (Breslow depth or Clark level) and even considering of the wide spectrum of patients deemed immunosuppressed, have further created uncertainty in the field. 31,[50][51][52] Currently, the use of multidisciplinary tumor boards (MDTBs) are known to improve outcomes in managing several malignancies. 53 MDTBs provide a platform for discussing treatment alternatives, improving communication among disciplines, and helping to develop tailored evidence-based treatment plans for the patient.…”

Current Methods and Caveats to Risk Factor Assessment in Cutaneous Squamous Cell Carcinoma (cSCC): A Narrative Review

“…Defining differentiation status can be complicated by the presence of focal areas of moderate to poor differentiation in a predominantly well-differentiated tumor, possibly explaining why some well-differentiated tumors can metastasize [ 43 , 45 , 47 ]. While proposed merging of moderate and poor differentiation status for purposes of risk assessment may mitigate some of this discordance, as well-differentiated lesions are typically more consistently recognized, some have noted that a binary system may increase the possibility of incorrectly upstaging tumors [ 48 ]. Ultimately, a more uniform designation of histologic grading for cSCC is necessary but poses challenges.…”

Pathophysiology, Histopathology, and Differential Diagnostics of Basal Cell Carcinoma and Cutaneous Squamous Cell Carcinoma—An Update from the Pathologist’s Point of View

“…In the case of cutaneous squamous cell carcinoma, it is necessary to carry out the differential diagnosis with a possible cutaneous metastasis of squamous cell carcinoma, such as in cases of squamous cell carcinoma of a pulmonary, head, or neck origin or a squamous cell carcinoma of the genital sphere. The genetic profile expresses mutations in the CXCL8, MMP1, HIF1A, ITGA6, and ITGA2 genes [1,[48][49][50][51]. A,B).…”