Assessment of Invasion Degree of Small Sized Lung Cancer Using Intra-Operative Frozen Section
Noriko Motoi, Wakako Hamanaka, Takehiko Oba, Shin Karita, Hiroshi Ono, Yuichi Saito, Seijiro Sato, Kentaro Inamura, Sakae Okumura, Yuichi Ishikawa. Japanese Foundation for Cancer Research, JFCR, Tokyo, Japan; The Cancer Institute Hospital of JFCR, Tokyo, Japan
Background: The number of small-sized lung cancer will be expected to increase under CT screening. Small-sized cancer can include surgically curable cancer which will be synonymous of histologically adenocarcinoma, in situ (AIS) or minimally invasive adenocarcinoma (MIA) of a proposed new IASLC/ATS/ERS classification in 2011.
Intra-operative frozen diagnosis (IOFD) might be able to help to decide the area of resection for limited operation of AIS/MIA. The purpose of this study is to evaluate the accuracy of IOFD, especially focused on invasion degree of small-sized lung cancer.
Design: Surgically resected 183 lung tumors which were less than 3cm in size were reviewed on pathologic factors of IOFD and final diagnosis (FD), and calculated concordance rate between them. IOFD was performed on HE stained slides of a small part of tumor. FD was made based on the HE and elastic stained slides of whole tumor. The examined pathologic factors were as following; pathologic diagnosis (PDx), presence or absence of invasion/minimally invasion area, histologic predominant subtype of proposed IASLC-ATS-ERS revision of AD classification and tumor differentiation. In discordant cases, the reasons were examined in detail.
Results: Among 183 lesions, 135 were primary lung cancer and 48 were metastasis from other organs. Primary lesions include 110 adenocarcinomas (AD) and 5 squamous cell carcinomas (SQ). Concordance rate for each factor is as following; 75.3% for overall PDx factors, 99.5% for judgment of benign or malignant, 97.0% for tumor type, 99.0% for tumor differentiation, 100% for predominant subtype of AD, respectively. Concordance rate for invasive degree of AD was as following; 75.0% for overall, 85.0 % for AIS, 41.0% for MIA, 100% for invasive AD. The reasons of discrepancy were based on tumor heterogeneity, sampling error, frozen section artifact, or some difficult rare cases.
Conclusions: IOFD can predict the final diagnosis of lung cancer in most cases (75.3%) and invasion degree of AD (75.0%). To prevent disagreement about PDx, pathologist should pay attention to tumor processing (sampling, sectioning and staining). To make accurate diagnosis of invasion degree of AD, a careful macroscopic observation to submit the proper area of tumor in which the most invasive area will be included is strongly recommended.
Monday, March 19, 2012 1:15 PM
Platform Session: Section D, Monday Afternoon