[2057] Accuracy of Frozen Sections (FS) in Predicting Predominant Histologic Subtype and Presence/Absence of Micropapillary and Solid Patterns in Lung Adenocarcinoma (ADC) ≤ 3 cm

Yi-Chen Yeh, Junichi Nitadori, Kyuichi Kadota, Akihiko Yoshizawa, Valerie W Rusch, Prasad S Adusumilli, William D Travis. Memorial Sloan-Kettering Cancer Center, New York City

Background: In lung ADC ≤ 3 cm, the choice between limited resection vs anatomical resection is an ongoing evaluation. The predominant histologic subtype in the IASLC/ATS/ERS ADC classification can provide prognostic stratification, but currently this classification is available only after surgical resection. If predominant histologic subtype and the poor prognostic micropapillary and solid patterns can be detected in FS, it can help intra-operative decisions for the extent of resection. The aim of this study is to evaluate the accuracy of FS to predict histology in final diagnosis, as well as interobserver agreement.
Design: 378 surgically resected stage I lung ADC were included in the study. All tumors are ≤ 3 cm. FS slides were examined for predominant histologic subtype and presence/absence of lepidic, acinar, papillary, micropapillary and solid patterns. The results were compared with final diagnosis in permanent sections. To test interobserver agreement, FS slides of 50 randomly selected cases were reviewed by two pathologists and 15 were reviewed by three pathologists independently. Kappa statistic was used to measure the degree of agreement.
Results: The concordance rate of predominant histologic subtype between FS and final diagnosis is 68.7% (Kappa=0.581). The sensitivity and specificity of FS to detect five major histologic patterns were shown in Table 1.

Table 1. Sensitivity and specificity to detect histologic patterns in frozen sections
Histologic patternSensitivity(%)Specificity(%)

There were substantial agreement on predominant histologic subtype between different pathologists (Kappa=0.729), and moderate to substantial agreement on presence or absence of five major histologic patterns (Kappa=0.648 for lepidic, 0.434 for acinar, 0.672 for papillary, 0.643 for micropapillary, and 0.610 for solid pattern).
Conclusions: There is moderate agreement on predominant ADC histologic subtype between FS and final diagnosis. The interobserver agreement is satisfactory. Because FS have a high specificity in identifying micropapillary and solid patterns, recognition of one of these poor prognostic patterns may help a surgeon to consider anatomic rather than limited resection. However, the value is limited by low sensitivity, especially for micropapillary pattern.
Category: Pulmonary

Tuesday, March 20, 2012 9:30 AM

Poster Session III # 315, Tuesday Morning


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