ABSTRACT Objective: To establish the accuracy of frozen section examination in identifying tumor spread through air spaces (STAS), as well as to propose a reproducible technical methodology for frozen section analysis. We also aim to propose a method to be incorporated into the decision making about the need for conversion to lobectomy during sublobar resection. Methods: This was a nonrandomized prospective study of 38 patients with lung cancer who underwent surgical resection. The findings regarding STAS in the frozen section were compared with the definitive histopathological study of paraffin-embedded sections. We calculated a confusion matrix to obtain the positive predictive value (PPV), negative predictive value (NPV), sensitivity, specificity and accuracy. Results: The intraoperative frozen section analysis identified 7 STAS-positive cases that were also positive in the histopathological examination, as well as 3 STAS-negative cases that were positive in the in the histopathological examination. Therefore, frozen section analysis was determined to have a sensitivity of 70%, specificity of 100%, PPV of 100%, NPV of 90.3%, and accuracy of 92% for identifying STAS. Conclusions: Frozen section analysis is capable of identifying STAS during resection in patients with lung cancer. The PPV, NPV, sensitivity, and specificity showed that the technique proposed could be incorporated at other centers and would allow advances directly linked to prognosis. In addition, given the high accuracy of the technique, it could inform intraoperative decisions regarding sublobar versus lobar resection. Objective STAS, , (STAS) Methods paraffinembedded paraffin embedded sections (PPV) (NPV) Results STASpositive STASnegative Therefore 70 70% 100 100% 903 90 90.3% 92 Conclusions prognosis addition (STAS (PPV (NPV 10 9 90.3 1 90.

RESUMO Objetivo Correlacionar a prevalência e o prognóstico de cada padrão de TCAR de pneumonia intersticial usual (PIU) típica, provável e indeterminada com o diagnóstico clínico multidisciplinar de doença pulmonar intersticial (DPI). Métodos Incluímos todos os pacientes com diagnóstico multidisciplinar de DPI com padrão de TCAR de PIU típica, PIU provável ou indeterminada para PIU. Dados clínicos e histopatológicos, teste de função pulmonar e status de sobrevida foram obtidos retrospectivamente. O diagnóstico final foi validado por uma equipe multidisciplinar. Resultados Foram incluídos no estudo 244 pacientes, com média de idade de 68 ± 13 anos sendo 52,5% do sexo masculino. Em um total de 106 pacientes com padrão típico de PIU, 62% tiveram o diagnóstico multidisciplinar de FPI, 20% de pneumonia por hipersensibilidade crônica (PHC) e 10% de DPI relacionada à doença do tecido conjuntivo (DPI-DTC). Dos 114 casos com provável PIU, DPI-DTC correspondeu a 39%, FPI a 31%, pneumonia intersticial descamativa a 11%, doença pulmonar relacionada a medicamentos a 9% e PHC a 8%. Nos 24 pacientes com TC indeterminada para PIU, o DPI-DTC foi o diagnóstico final em 33%, seguido por pneumonia intersticial descamativa (21%) e FPI (13%). Pacientes com PIU típica apresentaram maior probabilidade de morrer ou realizar transplante de pulmão no seguimento (17,9% e 11,3%, respectivamente). Conclusões FPI, PHC e DPI-DTC foram os principais diagnósticos diferenciais em pacientes com padrão de TCAR de PIU típica, provável e indeterminada. Pacientes com padrão de PIU típico na TCAR tiveram maior probabilidade de morrer ou realizar transplante de pulmão no seguimento.

ABSTRACT Objective To correlate the prevalence and prognosis of each HRCT pattern of typical, probable, and indeterminate usual interstitial pneumonia (UIP) with the clinical multidisciplinary diagnosis of interstitial lung disease (ILD). Methods We included all patients with a multidisciplinary diagnosis of ILD with an HRCT pattern of typical UIP, probable UIP, or indeterminate for UIP. Clinical and histopathological data, pulmonary function tests, and survival status were retrospectively obtained. The final diagnosis was validated by a multidisciplinary team. Results A total of 244 patients were included in the study, with a mean age of 68 ±13 years and being 52.5% males. In a total of 106 patients with typical UIP pattern, 62% had the multidisciplinary diagnosis of IPF, 20% had chronic hypersensitivity pneumonitis (CHP), and 10% had connective tissue disease-related ILD (CTD-ILD). Out of the 114 cases with probable UIP, CTD-ILD corresponded to 39%, IPF to 31%, desquamative interstitial pneumonia to 11%, drug-related lung disease to 9%, and CHP to 8%. In the 24 patients with CT indeterminate for UIP, CTD-ILD was the final diagnosis in 33%, followed by desquamative interstitial pneumonia (21%), and IPF (13%). Patients with typical UIP were more likely to die or had lung transplantation in the follow-up (17.9% and 11.3%, respectively). Conclusion IPF, CHP, and CTD-ILD were the main differential diagnoses in patients with HRCT patterns of typical, probable and indeterminate UIP. Patients with HRCT typical UIP pattern were more likely to die or had lung transplantation in the follow-up.