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OBJECTIVE: To investigate the value of intraoperative assessment of spread through air spaces (STAS) on frozen sections (FS) in peripheral small-sized lung adenocarcinoma. BACKGROUND: Surgical decision-making based on FS diagnosis of STAS may be useful to prevent local control failure after sublobar resection. METHODS: We conducted a multicenter prospective observational study of consecutive patients with cT1N0M0 invasive lung adenocarcinoma to evaluate the accuracy of FS for the intraoperative detection of STAS. The final pathology (FP) diagnosis of STAS was based on corresponding permanent paraffin sections. RESULTS: This study included 878 patients with cT1N0M0 invasive lung adenocarcinoma. A total of 833 cases (95%) were assessable for STAS on FS. 26.4% of the cases evaluated positive for STAS on FP, whereas 18.2% on FS. The accuracy, sensitivity, and specificity of FS diagnosis of STAS were 85.1%, 56.4%, and 95.4%, respectively, with moderate agreement (κ=0.575). Inter-observer agreement was substantial (κ=0.756) among the three pathologists. Subgroup analysis based on tumor size or consolidation-to-tumor ratio all showed moderate agreement for concordance. After rigorous reassessment of false-positive cases, the presence of artifacts may be the main cause of interpretation errors. Additionally, true positive cases showed more high-grade histological patterns and more advanced p-TNM stages than false negative cases. CONCLUSIONS: This is the largest prospective observational study to evaluate STAS on FS in patients with cT1N0M0 invasive lung adenocarcinoma. FS is highly specific with moderate agreement, but is not sensitive for STAS detection. While appropriately reporting STAS on FS may provide surgeons with valuable information for intraoperative decision-making, better approaches are needed.
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BACKGROUND: This study aims to assess the diagnostic accuracy of the intraoperative frozen section (FS) in determining the pathological subtypes among patients diagnosed with cT1N0M0 invasive lung adenocarcinoma. MATERIALS AND METHODS: This was a prospective, multicenter (seven centers in China) clinical trial of Eastern Cooperative Thoracic Oncology Projects (ECTOP-1015). Patients with cT1N0M0 invasive lung adenocarcinoma were enrolled in the study. Pathological images obtained from FS and final pathology (FP) were reviewed by at least two pathologists. The primary endpoint was the concordance between FS and FP diagnoses. The interobserver agreement for identifying pathological subtypes on FS was evaluated among three pathologists. RESULTS: A total of 935 patients were enrolled. The best sensitivity of diagnosing the predominant subtype was 78.2% in the evaluation of the acinar pattern. The presence of an acinar pattern diagnosed by FS was an independent factor for the concordance between FS and FP ( P =0.007, 95% confidence interval: 2.332-4.736). Patients with tumor size >2 cm measured by pathology showed a better concordance rate for the predominant subtype (81.6% vs. 74.6%, P =0.023). The presence of radiological ground glass opacity component did not affect the diagnosis accuracy of FS for the predominant subtype (concordance rate: 76.4% vs. 75.2%, P =0.687). Patients with ground glass opacity component showed better accuracy of the identification in the presence of lepidic pattern-predominant adenocarcinoma (82.1% vs. 71.0%, P =0.026). Substantial agreement between the FS diagnosis from three pathologists for the predominant pathological pattern was revealed with κ=0.846. CONCLUSIONS: This is the largest prospective trial evaluating FS diagnosing pathological subtype in cT1N0M0 invasive lung adenocarcinoma. A favorable concordance in the assessment of the pathological subtypes between FS and FP was observed, indicating the feasibility of utilizing accurate intraoperative pathological diagnoses from FS in guiding surgical strategies. A combination of radiology could improve the precision of FS.