Using frozen section to identify histological patterns in stage I lung adenocarcinoma of ≤3 cm: accuracy and interobserver agreement

Abstract

Aims The IASLC/ATS/ERS classification of lung adenocarcinoma provides a prognostically significant histologic subclassification. The aim of this study is to investigate the accuracy, limitations, and interobserver agreement of frozen sections (FS) for predicting histologic subtype. Methods and results FS and permanent section slides from 361 resected stage I lung adenocarcinomas ≤ 3 cm were reviewed for predominant histologic subtype and presence or absence of lepidic, acinar, papillary, micropapillary, and solid patterns. Fifty cases were additionally reviewed by 3 pathologists to determine interobserver agreement. To test the accuracy of FS in judging degree of invasion, 5 pathologists reviewed FS slides from 35 cases with predominantly lepidic pattern. There was moderate agreement on predominant histologic subtype between FS and final diagnosis (κ = 0.565). FS had high specificity for micropapillary and solid patterns (94% and 96%, respectively), but sensitivity was low (37% and 69%, respectively). The interobserver agreement was satisfactory (κ > 0.6, except for acinar pattern). Conclusions FS can provide information on the presence of aggressive histologic patterns – micropapillary and solid – with high specificity but low sensitivity. It was difficult to predict the predominant pattern based on frozen section mostly due to sampling issues.

Accuracy of the IASLC/ATS/ERS histological subtyping of stage I lung adenocarcinoma on intraoperative frozen sections

“…We found a 'moderate' agreement for the primary pattern, and only a 'fair' agreement for the secondary pattern. Our findings are similar to that of Yeh et al, 19 who reported unsatisfactory accuracy of frozen sections for histologic subtyping with also only 'moderate' agreement …”

“…This is similar to results reported by Yeh at al. 19 Interestingly, lepidicpredominant tumors showed a low sensitivity in our study (33.3%) and a very high specificity (94.4%). This result might be related to the fact that lepidicpredominant tumors showed a combination of acinar and lepidic patterns on the frozen sections and therefore were most frequently misclassified as acinar-predominant.…”

“…However, the accuracy of histological subtyping on frozen sections is relatively unexplored, and to our knowledge it was addressed in a single study only. 19 The aim of this study was to determine diagnostic accuracy and interobserver variability in histological subtyping of lung adenocarcinoma on frozen sections obtained at the time of intraoperative consultation.…”

How to deal with subcentimeter lung cancer: a moving target!

“…In a recent review of 361 resected stage I adenocarcinomas ≤3 cm frozen section analysis had a high specificity but low sensitivity for micropapillary and solid patterns (27). In a retrospective study of 803 patients with stage I adenocarcinoma the concordance rate between frozen section analysis and final pathology was 84.4% (28).…”

Surgical pathology of early stage non-small cell lung carcinoma

“…Particular attention was also paid to the identification of a micropapillary pattern, which was recognized with a 98% specificity rate when identified but was recognized with only a 13% sensitivity rate. Similarly, Yeh et al, evaluated 361 resected stage 1 ADCs in regard to accuracy of pattern identification, and additionally attempted to evaluate the accuracy of the presence of invasion at the time of frozen section in 35 cases (46). Similar to the Trejo Bittar study, agreement on the predominant histologic subtype achieved only a moderate a kappa value of 0.565 and again showed high specificity but low sensitivity for the identification of a micropapillary component.…”